Archive through February 14, 2006
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7171 Registered: May-04 | As seen elsewhere; this site wanders around quite a bit. When you need something to occupy your time, there's bound to be something on this page. http://www.1388.com/articles/ampdesign-english/index.html |
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Gold Member Username: John_aLondonU.K. Post Number: 3864 Registered: Dec-03 | Thanks, Jan. The whole site looks interesting, to me. http://www.1388.com/ I wrote above 'China now has its own, growing home market of discerning "audiophiles", I am sure'. The site shows the same is true for Singapore, where so much is manufactured. I have never bought the idea of assembly lines of people making mysterious products purely for export, while having no interest in what they do and whether what the products themselves are actually any good. It is human to want to be able to take pride in what you are doing. And everyone likes music, whether performed or convincingly reproduced. That is surely another reason to be cheerful. |
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Bronze Member Username: BcollinsRockport, MA United States Post Number: 45 Registered: Nov-05 | Has anyone here had any experience with the Cayin amps? Specifically the SA-88T? They claim it sounds like the MAC 275. Is this true? Lists for $1895 but retails for $1500. Is this any different in sound quality than Primaluna or Jolida? Thank you, Bill |
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Silver Member Username: Two_centsPost Number: 677 Registered: Feb-04 | There's a review of the Cayin amp in Stereophile by Sam Tellig who compares it to the Mac 275 that he owns. He thinks the Cayin falls short of the Mac. Not surprising. The review is still favorable. Then again, when does Stereophile ever print a negative review. Take it for what it's worth. |
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Bronze Member Username: BcollinsRockport, MA United States Post Number: 47 Registered: Nov-05 | Thank you Two Cents, Do you have a link to that review? Bil |
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Bronze Member Username: BcollinsRockport, MA United States Post Number: 48 Registered: Nov-05 | Thank you Two Cents, Do you by chance have a link to that review? Bill |
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Silver Member Username: Two_centsPost Number: 678 Registered: Feb-04 | Bill, the review doesn't seem to have been posted on Stereophile's website yet. It was in the December 2005 issue if you can get your hands on hard copy. |
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Bronze Member Username: BcollinsRockport, MA United States Post Number: 49 Registered: Nov-05 | Thanks, I'll try and track one down. Bill |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7223 Registered: May-04 | It should be mentioned the MC275, in new or original series, sells for around $4,000. I read the review and have seen the ads. Both bring to mind the description of "sounding like" the 275. After reading the review, I wonder just what aspect of the 275's sound they sound like. Not that it was a bad review; actually it faired quite well. The 275 and the Marantz 8B and Model 9 tube amplifiers have, for four decades, been comparison points for tube amps. (Along with the less expensive but well loved Dynaco ST-70.) While the general characteristics of those amps might be captured it is difficult to understand just how the newer amps can sound like something that used proprietary designs. (OK, Dyna's UltraLinear design is widely imitated now.) In the case of the 275 without the Unity Coupled Tranformer designs there isn't much to go on other than overbuild like the miltary was going to abuse the amp. |
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Bronze Member Username: BcollinsRockport, MA United States Post Number: 50 Registered: Nov-05 | Thank you Jan, I wasn't sure if it was just marketing hype or that there might be some similarities. Do you recall what they didn't like in the review? I'm considering ordering the amp if it comes even close! I just hate to purchase something I haven't listened to. Unfortunately all of the amps I am considering are only availible to me via mail-order. I'd love to know how the Cayin compares to other sub $2000 tube amps. If you or anyone else could recommend a tube amp that stands out from the others in that price range I would be forever grateful. I love the sound of the MC275 as well as other Mac amps but they are way out of my price range. I've heard good things here about the Primaluna P2 (also KT88) but thought that the Cayin might sound better due it's comparison to the Mac.(pretty naive eh?) Anyway, your feedback is appreciated. Thank you, Bill |
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Silver Member Username: Two_centsPost Number: 679 Registered: Feb-04 | Bill, If you love the sound of the MC275 and aren't adverse to buying used, why not get a used Mac. You can probably find one for not much more than a new Cayin amp. That way you own what you love rather than an approximation of the thing you love. Believe me, it's a more satisfying feeling to spend that little bit extra to get the real deal. Macs are solidly built and easily serviced so buying a used one that isn't too old shouldn't be much of a risk. Maybe Jan would be willing to sell you his Mac ;) |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2638 Registered: Feb-05 | OK Folks of the tubes. I am considering liquidating my home theater and going back to a simple 2 channel system for music. I will also play movies but they will be of far less importance. I have listened to the Prima Luna amps and have been very impressed. The combination that I am considering is this: Prima Luna Prologue 2 ProAc Studio 140 Audio Refinement CD Complete Alpha (I already have this piece). The reason for the potential change is that the system I have is complex and spread all over the living room of my little 1000 sq ft home. With rear speakers on stands there is simply no safe place in my living space for my grandchildren which makes their visits tense for everyone. I think it may be time to simplify for everyone. In the process I would like to improve the sound for music. Any comments on the pieces that I have chosen would be appreciated. I brought it to this thread because tubes are involved and because some of our most knowledgeable folks post here. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7226 Registered: May-04 | This is the best price I've seen on a 275 - ever! Usually they go for more like this: One thing about buying the real thing is the reliability of the Mac. You should not be too concerned about having the 275 in the shop and it will retain its value. However the Cayin sounds it will be worth half of its retail once you open the box. Art - The PrimaLuna and the ProAcs seem, to me, to be an odd mixture of personalities. |
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Gold Member Username: Rick_bOrlando, Florida USA Post Number: 1275 Registered: Dec-03 | Bill, If you have a chance, listen to the Sophia Electric "Baby". I think you will be amazed. I don't know your room size or speaker considerations, so factor that in when looking at a 10 watt amp. But what a glorious 10 watts! Art, Nice to see you still still posting! Going to tubes? It's about time! LOL! |
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Bronze Member Username: BcollinsRockport, MA United States Post Number: 51 Registered: Nov-05 | Thanks Two Cents, You make a good point. I considered used, but even used the MC275 is beyond reach. I would need to buy a preamp as well which would not be cheap. My only option at this point is to get the best sounding tube amp in my price bracket, which is kind of tricky since I am unable to audition any of them! - Also, I get the impression Jan is quite attached to his. Thanks again, Bill |
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Bronze Member Username: BcollinsRockport, MA United States Post Number: 52 Registered: Nov-05 | Jan, Thank you for those links. Reliability is a concern of mine. I'm not sure how I would have any waranty service done on one of the mail order amps. Kind of a pain to send it out of state if I have a problem. A tech person I know told me that the MC275 could be used without a preamp since it has a gain control. Would there be a loss in sound quality by doing this? Also, is there a significant difference in tube amps in the same price range that run the same tubes? I can order a Jolida from my local dealer, but I've heard that they have reliability problems. I'm not sure if they are any less reliable than the others I'm considering, but at least I would have a dealer to bring it back to if I had a problem. Thanks, Bill Rick, I've seen reviews of the little Sophia. Looks like it would be fun, but I don't think 10w would do it for me in my main system. Possibly a second system if finances ever permit. Thanks, Bill |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2639 Registered: Feb-05 | "Art - The PrimaLuna and the ProAcs seem, to me, to be an odd mixture of personalities." Perhaps. British speakers and tubes...hmmm. However they do seem to be a good match. The ProAcs are very efficient and have fantastic imaging and sounstaging characteristics. They aren't the last word in detail and transparency but they ain't too shabby either. Another seemingly odd match that I listened to and liked was the Prima Luna with the Naim Ariva speakers. They too are very efficient and share some other characteristics with the ProAcs. Where they differ is that with the Prima Luna amps they have a fatter or more plump sound. The low end is a bit less well balanced. The Naims were playing loud with the volume on the PL1 at 10:00 o'clock. Rick, It's good to see you are still with us if only just occasionally (wish it were more often). |
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Gold Member Username: Rick_bOrlando, Florida USA Post Number: 1276 Registered: Dec-03 | Art, Thank you for the kind words. Bill, I also have a Jolida tube amp, and have had no quality issues or problems. |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2644 Registered: Feb-05 | Have any of ya'll listened to the Antique Sound Labs AQ 1001 DT. Just curious. The search for a great inexpensive tube integrated is on. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7230 Registered: May-04 | |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7231 Registered: May-04 | Running any line level source into a power amp without any type of pre amp to provide constant impedance and buffering to the gain stages is a dicey affair. The gain comtrols in the old Macs are simple potentiometers which have OK but not great sound quality. The impedance of the circuit changes with the position of the volume control and there is usually only one correct position where the impedances match up to allow full dynamics and frequency response. Interconencts must be kept as short as possible and the interconnect shouldn't have excessive inductance or capacitance. If those criteria work in your system, then, yes, a CD player or DVD player can be run directly into the MC275. There is obviously no switching between components. If you run the system like this, you are usually running only one component as your source. Quite a few people at least start their systems with this configuration as they search for the pre amp they want to use. |
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Bronze Member Username: DarkmusicDover, Delaware Usa Post Number: 20 Registered: Apr-05 | Greetings! I also have a Jolida (707A). I have had no problems with the unit and I am very happy with it. Jan -- I replaced the stock 6l6s with winged c 6l6s. The sound is very clear. I also had the oportunity to move my xray cd unit to the MA6100 and the Ling IIs. This combination sounds fine -- I am not sure how this combination differs from the Jolida yet. I suspect the "edginess" I heard previously was due to a low-grade cd player that I had connected to the 6100 and Lings. Thus, GIGO. Have a good weekend, people. |
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Bronze Member Username: MrbeefyPost Number: 15 Registered: Jan-06 | Anybody have any opinions of Cary Audio Designs? I'm looking for a good tube and the SLI-80 (http://www.caryaudio.com/products/audio/sli80.shtml) has spiked my interest. I haven't had a chance to listen to it, but I figured you guys would probably have some thoughts on Cary's lines Thanks! any help is appresiated! |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7278 Registered: May-04 | Sorry, I've never had the opportunity to listen through Cary gear. |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2666 Registered: Feb-05 | Just ordered the Prima Luna Prologue Two with phono. Decided to keep my Paradigm Studio 20v3's. Very much looking forward to getting the amp and listening to all (yeah right) of my music again. New system configuration: Paradigm Studio 20 v3's Era Design Sub 10 Prima Luna Prologue 2 Integrated Amp Yamaha RX-V657 A/V Receiver (used as AM/FM/XM tuner) Audio Refinement CD Complete Alpha Denon DVD-2910 Universal player ProJect 1Xpression w/Grado Blue cart and Speed Box |
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Silver Member Username: Stu_pittNew York City, New York Post Number: 852 Registered: May-05 | Art - Please let me know how the ProLogue Two goes. I'm reading up on tube integrateds and plan on buying one around summer time. I'd love to do it now, but I'd like to get a few bills out of the way first. I think you said that you've listened to the PrimaLuna line before. Have you heard the ProLogue One? What made you choose the ProLogue Two over anything else you've heard/considered? The Two will most likely be the upper limit of my budget, and seems to be (without hearing any of the ones I'm looking at) my best candidate. |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2668 Registered: Feb-05 | Hi Stu, I selected the Prima Luna because it was so highly regarded by an audiophile friend of mine. I listened to the ProLogue One with a variety of speakers and found it to be delightful. I chose the Two due to the flexibility of being able swith out tubes in the future. I also like the auto bias feature on both the One and Two. The Prima Luna line appears to be very well built. I ordered it from a dealer who had been a Jolida dealer at one time. She stated that she had over a 100% failure rate with her Jolida products. When I asked how she could have over a 100% failure rate she stated that on the products failed twice. I believe that was a couple of years ago before Jolida improved their build quality. I had listened to a few tube integtateds before ordering this one but it came down to a choice between this one and the Rogue Audio Cronus (which is a nice product). I liked the Prima Luna sound a little better and Teri let me trade in my NAD C162 pre amp. To be fair to the Rogue, I was listening to it with speakers that I don't like as well as the ones that I listened to the Prima Luna with. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1084 Registered: Dec-04 | From stereotypes in portland, Art? Good luck, good call on the Paradigms. |
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Silver Member Username: Stu_pittNew York City, New York Post Number: 854 Registered: May-05 | Art - Thanks for your insight. I've also heard a lot of great things about the PrimaLuna line. The autobias feature seems to keep things simple for a soon to be first time tube user such as myself. I too was thinking that the ProLogue Two would be a better bet because it has more flexibility with tube swapping (is this the same as tube rolling?) than the One. After the "tube sound," the second main thing that turns me on to tubes is the ability to swap tubes in and out to custom tailor the sound to my liking. I know every tube won't work in every piece, but I'd like to have as many options as possible. I'd also be interested in how well your Studio 20's pair up with it. I was kicking around the idea of Studio bookshelves and a sub or Studio towers. I'd love to get the Studio 100's, but I don't know how well tubes would react to the impedence swings they supposedly have. I'd definately have to bring the integrated to the Paradigm dealer and listen for a while before I committed to that. |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2671 Registered: Feb-05 | Yep Nuck from Stereotypes. Teri is great! Yep Stu, Paradigms are famous for having wild impedence swings. You guys may have noticed that I chose to keep the Studio 20's rather than the 40's. The 20's don't sound quite as full as the 40's but they get the essence of music right. They just have a more coherent sound. They also seem have a wider soundstage. The do a better job of filling the listening room side-to-side than do the 40's. I really like the sound of a well designed 2 way bookshelf speaker. So as Stereophile pronounced awhile back "Tubes for Everyman" (and woman I presume). |
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Gold Member Username: John_aLondonU.K. Post Number: 3890 Registered: Dec-03 | Good luck, Art! Please post back with your impressions. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1086 Registered: Dec-04 | Stu, from what I have garnered so far, the 1 and 2 of tubes is #1 solid clean input power, balanced for 230 volt, well isolated to neutral ground for 120 volt.A ground spike is helpful with an isolated power supply or isolated 230 to 120 transformer. Second would be a balanced even load at the speakers. I read a piece from a guy in with Rega and Unico amps who could not get his sound right, until he shunted a meter with the speakers and found a calculated impedence swing way out of limits, yet no other indicators, as he was tapped at 4 ohms with the Rega. They were totems, he said, Rainmakers I think. So the load has to be stable, at 16 8 or 4, it seems. I am also poking around the tubes. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7300 Registered: May-04 | You are confusing the function of the power transformer and the output transformers on tube gear, Nuck. While the power transformer functions as it would in any conventional audio amplifier (other than the need to supply up to 700 volts), the output transformers are the matching device between the high output impedance of the tubes (several Ohms in some cases) and the impedance load of the speakers. While tubes generally prefer a stable impedance load (and so do solid state amps for that matter), the load doesn't require stability at a fixed impedance. If you'll read back through some of the archives to this thread, you'll see a discussion of how tapping the output transformers at other than the expected 4 or 8 Ohm load will alter, and further "tailor", the sound of the system. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1087 Registered: Dec-04 | I have a bear of a time with links inside the forum, Jan, I was referring to a thread from and with Tim on tubes and impedence with reference to the Lings. I have been following that route, as well as incoming power from yet another thread of yours. Dang, I will sort it out, they all have been removed(multiple users). I will re-find. Given the oft-interpreted esoteric nature of some tubes, would a VERY stable power supply not be preferable to a standard circuit, understanding that ss amps often have balancing factors and discrete limitors built in? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7305 Registered: May-04 | A "standard" circuit? What be a "standard circuit", Kimosabee? Stability is virtually always a good thing in any electronic device. But, that little "ly" at the end of any word makes it a somewhat interpretive term. One of the bits of delight in a Dynaco ST-70 is the power supply's ability to swing for the fences. A very loosely regulated p.s. in the ST-70 means it can swing along with the music. Large dynamic busts, when not followed by another large dynamic burst, sound much larger than on many other amps due to the ability of the amp to overstate its cause for just a fraction of a second. Of course, when that second 30Hz organ sustain hits immediately after the first few drum whacks, the ST-70 can get caught with its trousers around its ankles. So, the first thing most modifiers do is build up the power supply. Changes the entire presentation of the amplifier. Some of the magic is lost for the technical ability. It's almost a game of three card monte with a ST-70 when it comes to modding the unit. Keep your eye on the magic. Naturally, if you were asking me the question in reference to which amplifier you might purchase from me, I would always opt for the McIntosh route of massive over building at large expense. Nothing succeeds quite like excess. However, the loosely regulated power supply is hardly to be found only in tube amplifiers. It is a mainstay of budget gear and can be designed to work well given certain restrictions. It just works a bit better with tubes since the amount of voltage swing when dealing with 500-700 volt plate voltages has a different effect than when dealing with millivolts into a solid state device. Additionally, tube amps are not current operated devices such as bipolar transistors are. Tubes operate primarily with voltage so the large amperage drains seen in transistor amplifiers are much more easily accomplished when dealing with voltage swings and with much less capacitance in the p.s. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7330 Registered: May-04 | I don't remember if I have posted this link before. If not, it should be on this thread. If so, it bears repeating for any new comers. http://home.comcast.net/~enghenry/diy/taste.pdf#search='sonic%20t%20amplifier' |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2684 Registered: Feb-05 | Interesting read. Particularly if you're new to tubes like I am. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1121 Registered: Dec-04 | Thanks, Jan, that is a great link for another tube noob. |
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Bronze Member Username: DarkmusicDover, Delaware Usa Post Number: 21 Registered: Apr-05 | Hello People! Have any of you used the RCA 12AT7 and/ or 12AXT grayplate tubes (nos)? If you have, what did you think of the sound compared to other tubes in the 12at7/12axt categories? Thanks! |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7397 Registered: May-04 | It depends on where you will use them in the piece of equipment. There are seldom any NOS tubes that are as quiet as a Telefunken. If you value that in your system, then the Telefunken should be your first choice. Otherwise, the NOS American tubes should usually be considered good examples of the type of frequency balance and big sound that Americans prefer. |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2698 Registered: Feb-05 | Just back from Portland with my new Prima Luna and have been listening to it for 1/2 hr. Wow!! I'm sure this will not be my last stop along the tube road but oh my isn't a pleasant respite. My first thoughts were oh goodness this certainly isn't as articulate as I'm used to. Then it struck me how utterly easy to listen it is. The sibilance that I have been on occasion bothered by just wasn't there. Moreover it really isn't that it it's not as articulate the sound is simply richer and fuller. It appears as if I might be up late with a single malt and my favorite recordings. |
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Gold Member Username: Rick_bOrlando, Florida USA Post Number: 1291 Registered: Dec-03 | Just smile and enjoy Art. It only gets better! |
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Silver Member Username: My_rantzAustralia Post Number: 212 Registered: Nov-05 | Yeah, it will probably take a single malt, Art - or ten. You guys and your tubes - sheesh! You'll never get me! Me, I'm a modern man.  Glad you're back Rick. |
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Silver Member Username: My_rantzAustralia Post Number: 213 Registered: Nov-05 | Oh - and Art, congrats. Another room heater will be a benefit in your neck of the woods no doubt. :-) |
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Gold Member Username: Rick_bOrlando, Florida USA Post Number: 1292 Registered: Dec-03 | Thanks mate! |
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Silver Member Username: Two_centsPost Number: 680 Registered: Feb-04 | Art, Congrats on your new amp. Give the P2 about 50 hours to start sounding its best. The sound will open up. Based on my own listening experience the P2 doesn't lack in articulateness. Enjoy spending time with your new baby. Maybe you should light a cigar for the occasion, to go along with your scotch. |
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Gold Member Username: John_aLondonU.K. Post Number: 3898 Registered: Dec-03 | Good to read, Art. My first impression was of a lack of sibilance, too. But you can still hear the words. More clearly, in fact. I switched back to solid state for a while when my demo PL2 went back, and before the new one arrived. Pain. I'd really been listening to that all those years? I recall you have the phono stage. I don't, and don't have my turntable at present. How does vinyl compare? MR, "Modern man"? 'Strewth. No tubes, no vinyl, How very 20th century.... (Not wishing to incite audio intolerance etc., but "Sorry, no room in heaven, we've run out of NOS tubes"). |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2702 Registered: Feb-05 | Thank you for my welcome to the wonderful world of tubes. It's like I have discovered hifi all over again. TC if it gets better after 50 hrs I'll be crying with joy. "My first impression was of a lack of sibilance, too. But you can still hear the words. More clearly, in fact." John, I totally agree. The vocals and instruments are so articlate and seem to just leap from the speakers. 'Tis utter joy! Remember I was running an NAD C162 and a Hafler 9505 power amp (250 watts per channel into 8 ohms and 375 into 4) yet the Prima Luna amp fleshes out more detail more fully than the other combo could...period. I hooked up my Era sub as it is one of the finest subs I've had the pleasure of hearing. When I first sarted listening last night I was amazed at how good and tight the bass was. Then I noticed that I hadn't even turned on the Era yet. The Prima Luna makes my Studio 20's sound like I have never heard them. Full rich bass, in proportion to rest of frequency presentation. John, I haven't hooked up the table yet. Believe it or not, construction on my home remodel starts next week and I have to box up the whole system for a month. Oh bummer!!! I'll be listening to my Cambridge CD 740 radio for awhile. Much more to come later. Exciting news from Prima Luna. This year they intend to release a bigger integrated w/remote. Personally I'm cured of the amp upgrade bug for sometime but thought you might wanna know. |
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Silver Member Username: Stu_pittIrvington, New York USA Post Number: 891 Registered: May-05 | I'm glad to hear you're enjoying the amp Art. I'm trying to knock down as many bills as I can over the next few months before I put myself in debt all over again. This time it'll be for a good cause though... |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1163 Registered: Dec-04 | Good for you, Art! Must seem like pennance to have and pack it all, lovingly, wistfully back up again. Sniff. It will be back, however, and you will have the sound of hammers, scrapers and various abrasives to keep you company. Kind of like listening to CV's if you like! |
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Silver Member Username: DakulisSpokane, Washington United States Post Number: 799 Registered: May-05 | Art, Say it ain't so!!! Actually, welcome to the club. I just couldn't make the HT system work in 2 channel to my liking. Now, if I ever get the other woofer back and repaired for my ALs, I'll be back in heaven. I'm still using the Heritages from my friend but they're just not as good a speaker as the ALs, especially with the tubes. It's amazing what these brightly lit little babies do to music and I've been away for 30 years almost without tubes, what the heck was I thinking when I trashed the Luxman, huh? Jan, great call on the new article post. A friend of mine suggested it so I printed it and brought it with me to Maui for light reading. I'll comment further after I get done reading it and after I finish the fresh pineapples, mangos and my guava juice. Geez, all this sunshine, sand and waves is tough to take. Is it over 40 degrees in Portland area, Art? LOL |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2718 Registered: Feb-05 | Hi David, It is so, I'm a "Tube Man" now. There is no goin' back. I now listen to my favorite music by the glow of those lovely KT88's. Sorry David, can't get to me with the Maui thing. It's one place I have no desire to be. Much rather be in Seattle than Maui. Enjoy the sun and sand! |
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Silver Member Username: DakulisSpokane, Washington United States Post Number: 800 Registered: May-05 | Art, I will say this, there's no decent audio stores over here BUT the beaches do have some interesting diversions, involves the eyes more than the ears, though. Seattle when it's sunny it's incredible but Maui is a pretty nice change from Spokane this time of year. I've been reading Jan's string on the T amp and I'm not falling for that one. I don't need another amp, I love my Fisher!!!! Good night, it's bed time all and this is my 800th post, dang all that work has really cut into my time on the site. LOL |
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Bronze Member Username: PaulfolbrechtPost Number: 42 Registered: Dec-05 | Hey guys.. have to post this here.. see what ya think. I picked up a Woo Audio 3 headphone amp for the office this week. I am breaking it in a bit tonight in my home system as my preamp. Something happened that I did not expect: IT WOWED ME! It sounds better than my PrimaLuna 3 pre that costs almost 3x as much! It sounds so damn good I want to dump the PL and get another Woo for home. Can anyone 'explain' this, to any degree? The Woo is OTL and single-ended - can this explain what I'm hearing? What I'm hearing is better resolution and clarity. What struck me first was track 10 on Pink Martini's Hang on Little Tomato - there's a cowbell that just sounds 10x better out of the Woo. I switched back and forth literally 8 times to confirm what I was hearing! Just thought I'd pass this along. And see what others think. I will listen a bunch more but if it holds up I will dump the PL on Audiogon and pick up a Woo2 for $995. Paul |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7461 Registered: May-04 | Single ended and output transformerless? Never mind the other stuff, tell me how that happens. What output tube is used and how many are paralleled to get the OTL to work? What kind of output power? |
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Bronze Member Username: PaulfolbrechtPost Number: 43 Registered: Dec-05 | http://wooaudio.com/products/wooaudio3.html Around 2W, I think, but I'm certainly not pushing it that hard. It's a pair of 6922s and one power tube, I forget which. After a couple hours' listening, the Woo does some things better and the PL does some things better, and it's quite hard to put a finger on what is what. The PL seems to have more low-end punch. Perhaps the 'forward' cowbell was nothing more than a coloration. I don't know yet. I do know I could sell the PL for more than enough to buy a Woo 2 to replace it. Anyway this is a killer preamp for $470. Has only one input though. Paul |
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Bronze Member Username: PaulfolbrechtPost Number: 45 Registered: Dec-05 | Hey Jan, On a related note what is your opinion of the PL products, in terms of design and specs? Just curious. I don't know if you've heard them or not - just wondering what you think of the designs mainly. Also, are you familiar with Jones' 'Valve Amplifiers'? Picked this book up and will read it at some point in the near future. Paul P.S. Another hour on all PL again and I'm liking it as well.. hmm.. subjective stuff, sometimes, this audio thing. The little Woo is most definitely DIFFERENT, but I'm having a hard time deciding which is BETTER. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7465 Registered: May-04 | Ok, you had me going there. It's a pre amp! Yeah, yeah, and headphone amp. Though I doubt it does low impedance (8 Ohm) headphones very much justice. Certainly almost any decent tube pre amp will be single ended, class A and OTL. Other than in a professional studio system, I can't remember ever seeing a tube pre amp with an output transformer. There's no need with the input impedances the pre amp is likely to work into. The description of the pre amp sounds a bit like they are playing on people's ignorance. I've not heard the PL designs. I don't think they are being carried by any shop in Dallas. They have been very successful elsewhere, I know that. |
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Silver Member Username: DakulisSpokane, Washington United States Post Number: 802 Registered: May-05 | Hey guys, Just finished "A Taste of Tubes" and it's a good read and I know a little more than I knew before although some of it went over the windshield. It well worth the read and Jan posted the site earlier up this page. More to report when I get back to Spokaloo, I suspect and everyone keep enjoying. Art, I'm waiting for a full blown review on your new system. |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2734 Registered: Feb-05 | Sorry David, like I told you awhile back I don't do full reviews, I just don't have time for it. I give general impressions and highlight the differences. I have done that a bit already. Now I'm waiting for the amp and speakers to break in, which will have to wait until after my remodel is finished. I have one more week to listen as the contractor has pushed out demolition until next weekend. Then I will be without music for 2 weeks or more. Tragic! |
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Bronze Member Username: PaulfolbrechtPost Number: 47 Registered: Dec-05 | Jan, I'm very curious to hear why this amp would have difficulty with low-impendence cans. Obviously it has to deal with the OTL design.. I realize the lack of an output transpormer makes impedence matching important but don't understand the details. Anyway, the cans I plan to use with it (AT 900ltd) are about 40 ohms.. which, of course, is actually waay low compared to most Sennies and Beyers. Thanks, Paul |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7475 Registered: May-04 | Yes, it is a function of output impedance vs. input impedance and the dificulties tubes encounter when they are run into low impedance loads. The function of the output transformer on a tube amp is mostly to aid the high impedance output of the tubes (often up around a few Ohms themself) mate well with the low impedance input of the most common speakers(often around six Ohms over their frequency bandwidth). That is the reason the output transformers will usually have taps at various impedances. As the speaker's (or headphones) impedance approaches the output impedance of the power amp, the amplifier will exhibit undesirable fluctuations in frequency repsonse and the power transfer of the tubes will suffer, which will lead to complications of driving a speaker that would prefer to be driving the amplifier. Headphones are typically a single driver so there is not much problem with phase angle and the small driver size doesn't present much in the way of back electromotive force but the headphones will still have an irregular frequency resonse and probably would reach higher SPL's with a solid state amplifier of the same output voltage. Your 40 Ohm AT's should do much better than an 8 Ohm headphone. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1190 Registered: Dec-04 | Jan, you say the speaker trying to drive the amp.Is this the CEMF generated within the coil and magnet generating this force? Is yes, is this themajor determing factor when we say a particular speaker is 'hard to drive'? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7478 Registered: May-04 | Don't know no "C"-EMF. I know "Back"-EMF. Which is the force of the driver's motor system (the coil moving in the magnetic gap) generating AC voltage. This voltage has to go somewhere and the only possible place it can go is back through the wires that lead to the amplifier's outputs. Obviously in a tube amplifier the output transformers would absorb the voltage and not let it pass to the tubes. In a solid state amplifier various devices (often capacitors or autoformers will be used to shunt this voltage to ground) will hopefully have the same effect. While this has a part to play in how difficult a speaker will be to drive by any particular amplifier, this reaction is a result of the amplifier's design, not the speaker's. The role the speaker plays in this arrangement is determined largely by the overall impedance characteristics of the driver and the additional effects of the components in the crossover. The driver's motor assembly is a coil and therefore an inductor that changes values as it heats up in use. Heat also changes the values of the resistors, capacitors and coils in the Xo. How little or how much change occurs depends on the quality of the components. While the driver can be designed with a heat sink of sorts in place, the Xo usually isn't. So a Xo that begins with a difficult to drive impedance and electrical phase angle will typically get worse when heat begins to affect the components. But for the most part, the intial effects of the caps' and inductors' phase relationships (90° positive or negative)} will determine how difficult the speaker will be to drive. That and the efficiency of the drivers. When coupled with low impedance, the phase angle asks for lots of current to be dumped instantaneously by the amp. Those speaker systems which also have dramatic peaks in impedance (which most reflex designs will exhibit) or "wild" swings of impedance across the bandwidth make the job of the amplifier even more difficult. The output impedance of the amplifier will make the job either more or less efficient in the transfer of power. This also rises and falls with output and frequency. So, now we're back pointing fingers at the amplifier. It's a wonder this stuff works at all. |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2740 Registered: Feb-05 | David, I've read a couple of reviews of my amp this morning and I believe that this one comes closest to expressing what I've been hearing. http://upscaleaudio.secure-shops9.com/primaluna/hifiplus112004complete2.pdf BTW - I have backed off selling that Era sub. Clean 100db at 25hz is difficult to give up. I'll wait until after the remodel to try to work it into the system. |
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Bronze Member Username: PaulfolbrechtPost Number: 49 Registered: Dec-05 | Jan, Thanks for more of your insights (I've had a fair understanding of most of this stuff - amp/speaker interactions.) One more question for you - if you care to offer an answer, or perhaps provide a reference. It's about tubes and why this Woo sounds different than the PL - is it the tubes? The Woo uses a pair of 6922s while the PL using one each 12AX7 and 12AU7 per channel. Is there anything in general that's known about the sonic characteristics of these tube categories? Anything that might explain what I'm hearing? Tubes really bring this hobby to a new level of fascination and interest for me. Paul |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7480 Registered: May-04 | Depending on how much you want to hear, all tube types will have a slightly different presentation. Lots of tubes are no more than substitutes for another tube and items such as a 12AX can be considered more or less similar to a 12AT7 though with different amounts of gain in each tube. Many small signal tubes can be substituted for another small signal tube by rewiring the socket. But I don't know how to tell you what each tube sounds like. Some listeners consider all tubes of the, say 6550 type, to be interchageable and have similar sound. Other listeners anguish over whether the color of the plates is grey or black and whether the ends are flat or fluted. Most assuredly the market hype that often surrounds new old stock tubes has promoted just this sort of dependency on buying just the right tube and not just any 12AX7 black plate. (Are the pins gold plated or mere nickel.) To add to that, some same type tubes which might be preferred in a phono pre amp could be bettered in a power amp driver stage. In general tubes vary according to several measurements that are designed in to make all 12AX7's interchangeable. Some have high this or that characteristic and others mid or low in the same area. Some tubes that are popular today were never designed for use in home audio equipment but have found their way to the market by way of test equipment or television use where high frequency linearity is important. What many people getting a taste of tubes for the first time fail to realize is the exact same tube may sound very different when placed in a different circuit. The voltage range for a tube to operate is going to affect how the tube sounds, whether the tube is in a fixed or auto bias circuit or must be adjusted to acccomodate wear. The load the tube works from and into will alter the sound of the tube slightly. Cathode follower or cascade output? So, you see, I could go on and on about a 6922 sounding like this and a 12AX7 sounding like this. But, in my estimation, I would be wasting my breath since there are too many variables to consider. If you read the tube seller's web pages, you will get an idea of the general characterisitcs of a tube's sound. But those folks are very careful to tell you the description is merely the most general idea of what to expect and, if it turns out totally different in your amplifier, they are not responsible for what you hear. Now, if the Woo (which I don't know at all) is a single ended, OTL that you are able to use to drive loudspeakers, there are lots of reasons that could be given for what you are hearing. This would be particularly true when it is compared to a push-pull transformer coupled amplifier. Not to mention you are listening to a small signal triode vs. a power pentode. One truism that I found generally holds water in tube power amplifiers is the quality of the output transformer and, to an extent, the power transformer will largely determine what you hear from a tube power amp. Additionally whether the amp is connected as a single ended, Ultralinear or Unity Coupled gain stage will have quite a bit to do with the final results. How the driver and gain stages are developed will alter the sound of the amp. And so on, and so on .... |
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Bronze Member Username: PaulfolbrechtPost Number: 50 Registered: Dec-05 | Jan, Thanks for all that, and to clear up a misunderstanding (I think), I am NOT driving speakers with the Woo - I'm driving my 70W PL monoblocks. I just substituted the Woo for the PL 3 preamp that was doing same. Just the change in preamp is responsible for the sonic differences. Which is not terribly surprising in itself, I guess, but the degree of change, audible only on certain tracks, was. Paul |
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Bronze Member Username: PaulfolbrechtPost Number: 51 Registered: Dec-05 | A bit more on the Woo vs. the PL 3 as preamp. Woo specs: Input impedance: 100 Kilo-Ohms Signal/Noise: 95 dB THD: <= 0.08% Pre-amp Gain: 10 dB PL specs: Input Impedance: 100k Ohms S/N Ratio: 109 db unweighted THD: Less than 1% at full power Gain: 11.5 dB Perhaps, Jan - if you could be so kind as to lend assistance yet again - you could help me unravel these stats a bit in terms of real-world performance (or, perhaps, tell me that I'm barking up the wrong tree in general in looking at the numbers). 1st, we see that the Woo boasts only .08% THD. These strikes me as a very low THD figure for a tube amp - then again, we read again and again and again how meaningless THD figures are. We also see that the PL boasts a much higher S/N ratio - but its figure is quoted as "unweighted", and I don't know the meaning in this context. Perhaps this is not apples-to-apples. Woo offers less gain but I would guess that means nothing. At the same output vol, the gain will be the same. Do these numbers tell us anything about what we should expect to hear from these amps? Or are there just too many other variables (the tubes, for one!)? Thanks again for any insights. Perhaps one day this thread will contain all anybody needs to know about tube amps! Paul |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7482 Registered: May-04 | What you see in those specs is meaningless unless they are placed in context of all the other numbers within the two pre amps and the system the pre amp is working with. They are there to make the buyer feel like the designer has some idea what they are doing and not just throwing components in a box. THD is relative to what frequency, what output level, what input level and impedance, etc. How much THD can we hear and is it the worst type of distortion? "Weighted" numbers, particularly noise numbers, are a way for the manufacturer or measurement taker to get around certain facts of life. Without a reference to anything from one component to another they are not worth much and even if you know the measurement was "A" weighted it is still meaningless unless you know what is thrown out to get to "A" weighting. This page refers you to articles that are slightly to mostly technical, but, I think, readable by most people with a vague understanding of electronics; a group where I include myself. http://sound.westhost.com/site-map.htm Most answers to basic questions can be found here, if you know where to look. |
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Bronze Member Username: PaulfolbrechtPost Number: 52 Registered: Dec-05 | Thanks, dude! Holy cow, this is the mother-lode! I can't wait to go through all this stuff. :-> Since I can't stand the thought that my preamp might be holding my system back, or possibly just not giving me more of what I want, I think I will buy-to-try a few pres in the under $1200 bracket and keep the one I like best. MiniMax, Cary, Woo 2. After 5+ hours listening, I do prefer the Woo over the PL. I have several discs where the Woo really shines. Another is Willie & Lobo's Gypsy Boogaloo, where the percussion instruments show much better imaging and air. Kevin Deal at Upscale explained that the PL is in no way inferior, just different, and he seemed to imply that the Cary preamp would give sound closer to what the little Woo delivers. The PL does have those 'syrupy mids' which are great and of course many ppl just love. I prefer airy and extended highs. Paul |
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Bronze Member Username: PaulfolbrechtPost Number: 53 Registered: Dec-05 | I can now identify pretty readily exactly what is different betwixt the PL and the Woo: the latter gives more extended, airy highs but at the expense of the super-lush mids of the PL unit. That's it in a nutshell. At first, these lovely highs struck me as "better" all-around only because, I think, it was new - after a bit, my attention was able to return to the mids where the lack of warmth became evident. I've switched my interconnects back and forth probably 20x the last few days and have listened intently for 8+ hours. I'm pretty much leaning towards the Woo sound as what I find preferable. This exercise has impressed upon me how much power the preamp has in defining the sound, and convinced me to audition a couple more units, of different construction techniques. The MiniMax preamp is about the ultimate in simplicity, a super-steal at $800, and gets reviews that are pretty astounding (learning to read between the lines, you see that a ton of budget gear is tagged "giant-killer" but this is one case it seems to be true, the reviews goes that extra mile in praising the unit, and I can testify that their CDP is an outstanding product so I'm confident in the firm and the designer). I already have a representative of OTL design in the Woo 3. If the Woo wins my auditions, I'll order a Woo 2 (under the assumption that it'll sound the same, which I'm told by the designer is the case). Then there is the Cary AE-3 DJH, another very highly regarded unit, and supposedly a steal at $1200 (all of the other units I'm considering are cheaper than the PL 3, actually). This is not OTL but is direct-coupled, and supposedly as "fast" as tube preamps can get. When I'm done, I'll have two very slightly used preamps to sell, and I'm planning on recouping 80% of my cost at least. (Since the PL went up in price the week after I bought it, I should be able to get nearly what I paid out of it, should it not come out on top.) Given that no dealers in my area carry this gear (I had a MiniMax dealer 2 miles away but he stopped carrying them!!), much less anybody offering home trials, I think this is about the most cost-effective way to audition gear. I WILL hold out a bit to see if I can pick up a used specimen on Audiogon or Ebay. I can continue to post my observations here, but I don't want to bogart this thread - I'm a guest here. :-} So, if any of the resident rulers would like me to take it elsewhere, just say the word. Paul |
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Bronze Member Username: BcollinsRockport, MA United States Post Number: 69 Registered: Nov-05 | Keep it coming Paul, Bill |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7489 Registered: May-04 | Paul - I won't and can't argue with what you are hearing. I would advise though to be certain what you are hearing as "open, airy, highs" amount to more than a simple rise in frequency response which could lead to fatigue over the long haul. The 12AX7's in the PL have a classic dual triode "sweetness" that is a long standing favorite of tube users. But the various tubes that have come to replace the 12AX7 (6922, 6NS7, 6DJ8, etc.) have many favorable qualities also. Listen and use a good reference point (live music) as your guide. There seems to be a bit of a misunderstanding regarding OTL designs. OTL power amplifiers are an uncommon beast that lurks in the dimly lit recesses of audio salons with unmarked entrances and the basements of some (very geeky) listeners. OTL pre amps, on the other hand, are quite easy to find. As I said, other than some studio applications, most tube based pre amp designs are OTL's. OTL power amplifiers require lots of tubes wired in parallel to lower the output impedance and look similar to this: http://www.1212designs.com/OTL_Stereo_Amp/ The great number of tubes becomes a necessity when trying to drive a near universal application of loudspeakers which can easily include a 84dB system with an impedance curve that dips and peaks between 2 and 36 Ohms. Hopefully the person investing in an OTL undertsands the complexities they are headed into. But such was not the case in the late 1980's when the Futterman amplifiers made a brief resurgence. Many listners purchased Futtermans to pair with HP's favorite d'jour Infinity Reference towers and found themself owning large, expensive, and melted down boat anchors. The need for that type of parallel drive is unnecessary when dealing with headphones, even the 8 Ohm variety. But the OTL portion of your Woo seems to be referring to the unit when used to drive headphones and not when used as a pre amp. Or, at least that's the way the web site reads and it would make sense for it to be constructed in such a fashion. As a pre amp, the Woo seems to be a more or less conventional design that would have no need for transformers at the outputs. So, in comparing pre amps, you will be comparing the OTL Woo to a Cary which is also OTL. The following might help you understand the use of OTL designs in headphone amplifiers. http://www.headwize.com/projects/ciuff_prj.htm http://www.glass-ware.com/tubecircuits/Tube_Headphone_Amplifier.html Also, I'm not certain what exactly the pages of the Woo and the linked ampilifiers are referring to as SE, or single ended. Single ended can be used as a term of description for a simple gain stage amplifier, as in Single Ended Triode Amplification. Most tube based pre amps are single ended operation in class A. (Actually, most pre amps with any type of amplification device operate in single ended class A since there is no need for the high voltage or high current delivery that would necessitate a push-pull circuit.) In this case the term SE means not a push-pull circuit. Or, the term single ended can also refer to the input/output configuration of the circuit. In this usage, single ended means "not balanced" or "unbalanced". A single ended termination is, in consumer audio, (unfortunately) typically a RCA connection, which by its nature can only be an unbalanced line. A balanced output is more typically accomplished with the use of three pin XLR's. This three pin design allows the signal, return and shield to be separated from each other and not combined as signal and return/shield as they are in an unbalanced circuit. (The balanced circuit will have a 6dB lowering of circuit noise over single ended operation due to this separation of signal paths.) It would appear the designers in the above links are referring to the output configuration and not the circuit operation of the gain stages. (Though to be even more confusing, a consumer audio single ended triode amplifier is most likely going to be a single ended output configuration. Yet, it is possible to construct a single ended gain stage with a balanced input and output. It is, however, impossible to construct a balanced circuit that will terminate in a single ended connection. [Unless you utilize transformers and forgo the advantages of the balanced circuit operation at the outputs.]) Make sense? |
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Bronze Member Username: PaulfolbrechtPost Number: 54 Registered: Dec-05 | Jan, I have indeed been wondering if the "better highs" are indeed nothing more than a coloration! How to tell? I don't know exactly how a lot of these strange percussion instruments sound live. The system as a whole does not sound bright, and has not been fatiguing. But, you may be entirely correct in that suspician. I was aware that OTL in terms of power amps is an entirely different beast, as you point out. Tubes driving speakers directly is, well - a bit different, indeed! And really rare. But, it appears I was unclear in OTL as it applies to preamps - thanks for clearing that up. I guess the Woo is not at all unique in that area. Re: single ended: I had assumed they were definitely talking about the output and not unbalanced/balanced! I thought balanced outputs were always stated in exactly those terms - but, maybe not. So, yeah, by "single-ended" I had assumed they meant "the opposite of push-pull" - one tube handling both + and - components of the signal. I had also assumed the headphone and pre-out circuits were identical, but maybe that is not true either. (By the way, the amp does sound great with my Audio Technica 900 cans.) So, I think I followed you, and learned a couple things. (Another is that last tidbit. A bit over my head, but I think I've got it.) Anyway, here's the latest revelation: I've discovered the Woo is lacking in low bass as well. Previously, I was audioning with no sub because the Woo has only one set of outputs. To make it even, I didn't use the sub with the PL either. Well, I discovered I had on hand the Y-adapter to put the powered sub in the circuit with the Woo, and thus revealed this deficiency. Thus, it seems the PL bests the Woo in the mids and lows. (And when I say that, I'm assuming that the extended highs of the Woo are not a coloration.) Given this weakness, which is something I really could not live with (I like bass), the PL is definitely back on top now! And maybe I don't need to audition anything else, either - I'd plumb forgot I can tube-roll this PL and have low-$ fun for weeks that way. Maybe I'll hit a more satisfying combo that way without buying another peice of equipment. Definitely somewhat subjective stuff, this process. Meaning, sound may not change between listens, but what you concentrate on (and thus, hear) can. I guess this shows I'm not an expert listener. Paul |
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Bronze Member Username: PaulfolbrechtPost Number: 55 Registered: Dec-05 | Oh, yeah, of course I could make up for the Woo's low-end deficiency by simply turning up the gain on the sub... it's an idea. But, it is lacking at higher freqs than I care my sub to handle (I keep the xover at around 40Hz). |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2744 Registered: Feb-05 | Well guys everyday I enjoy my PL2 more. It is the most significant change or shift in terms of audio quality that I've experienced in my own system. It's made me appreciate every piece of my gear more and even more significantly I'm getting more pleasure from my music than I ever have. The only upgrades I'm looking at would be interconnects and speaker cable but that won't be for quite sometime. I am also interested in a better turntable but not yet. First I'm going to spend a significant amount of time with this system as-is and get to know it well before I change anything. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7495 Registered: May-04 | Good thinking, Art. You can't improve on what you have until you realize what needs improvement. |
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Bronze Member Username: PaulfolbrechtPost Number: 56 Registered: Dec-05 | What kind of interconnects are you running now, Art? I bought one "higher end" interconnect as an experiment - the 1st Wireworld model that's silver. Around $300. Could not detect a difference over my $150 Kimber Hero either from CDP to pre or pre to power amp. Luckily it was a "demo" cord that only cost me $200. OTOH, bi-wiring my speakers and going to high-grade wire (Nordost) made a huge difference everywhere. I have a couple hundred hours listening to the system now and, the urge to tinker aside, and despite this latest flirtation with another preamp, yes I have been thilled with the PrimaLuna products. |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 2746 Registered: Feb-05 | Paul, I have a friend who owns an audio store in Corvallis who puts together cables using this wire. http://www.jscwire.com/jsc_ss.taf?p=3060 My speaker cable is Liberty Cable 12AWG Ultracap. The speaker cable is $2 per ft or $4 per ft biwire. The interconnects cost $25.00 if you aren't a customer and $25 if you are. They have kind of a dark presentation but I haven't heard anything more detailed for less that several times their price. I have however heard better and you how that tempts us. But as I said before I'm going to leave well enough alone for awhile. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1215 Registered: Dec-04 | Paul, you have really added a lot to the forum. Someone with so much interest, and the means to aquire so many high quality items are great. Reading the posts and links(thanks Jan) are really good info. Please continue to post at will, as your input really gets the good info going. Your PL thoughts are right inline with Art's, and he is loving his gear for certain. Imagine, Art, how good it will sound with rainbow foil! |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7502 Registered: May-04 | Dr. Gizmo on OTL's: http://www.meta-gizmo.com/tri/otldebate.html |
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Bronze Member Username: PaulfolbrechtPost Number: 58 Registered: Dec-05 | Jan, My stupid questions for the day. 1) Trade-offs of one driver tube/rectifier per ch vs. two? The PL 3 has one AR5 rectifier per ch as well as one each 12AU7 and AX7. The MiniMax does it all with one. It seems to me, theoretically speaking, that combining the channels to run them thru the same stage and then splitting them again is, well.. not so ideal. I started thinking about this as I was about to order some NOS tubes for the PL and went through this thought process: - These tubes are EXPENSIVE. - It'd be nice if I only needed HALF as many tubes. - Yeah, that'd be nice. - But would it sound as good? I've heard other opinions on this matter, but I'd like to hear yours. What do you know, that's the only stupid question I have at the moment. Thanks as always. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7517 Registered: May-04 | Do me a favor and provide links to each amplifier's web page. I would be very surprised if the rectifier tube shares duty as a signal tube. |
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Silver Member Username: DakulisSpokane, Washington United States Post Number: 804 Registered: May-05 | Art, Good review and I think I get what you're hearing. Congrats. Now, if I could just borrow two of Tim's Emmas for awhile, I suspect I would be in heaven. Dave |
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Bronze Member Username: PaulfolbrechtPost Number: 59 Registered: Dec-05 | No, I didn't mean that. I meant the MiniMax uses ONE tube for rectification as opposed to the PL3 TWO - one for each channel. Similarly, the PL3 uses 4 driver tubes - two for each channel - to the MiniMax's two total. In other words, the PL3 is dual-mono and the MiniMax (and many other preamps) is not. I would guess it's hard to argue that dual-mono is not theoretically superior, but... 2x the tubes. At $25-50+ each, OUCH! Paul P.S. http://www.upscaleaudio.com/product.asp?itemid=499&catid=36 http://www.morningstaraudio.com/shop/item.asp?itemid=1 |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1257 Registered: Dec-04 | 3 quick points. Paul, I have never seen a stupid Q from you, althought I appreciate your self-deprication. Jan, as usual, your knowledge is well renowned(sp) and always appreciated. Art, you must be in denial by now, enjoy the sound of sawlence(apologies to garfunkel). Dave, where are you with the Lansing driver repair? Okay thats like 4 or something. 4 shots for a half bit. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1267 Registered: Dec-04 | Dave, rub off the caruba wax and come back home to the real world. Sorry.Real world.thud! sorrry. (do you think I am jealous? Oh no, not at all.Cheers! |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7518 Registered: May-04 | Theoretically dual mono is superior. However, theory often doesn't meet reality. Parts quality trumps parts count every time. Over spec'ing the parts usually beats perceived parts quality. A lower quality polystyrene cap with a polypropylene bypass will probably sound better than a lower capacity polypropylene by itself. It would be simple to make a case for or against each pre amplifier depending on what I wanted to sell, if I were arguing only the technical merits. To begin with you would want to look at the internal view of each pre amp and there you would find the Mini to be a very simple circuit. It is difficult to argue the more complicated circuit is the better choice when simplicity of design is a selling point of tubes. The Mini is by far the simpler cirucit. That should make a for a signal path which is closer to a "straight wire" with gain. Except to get the same amount of gain from both circuits, the Mini will have to be run harder, and closer to its limits (more potential for noise and distortion) than the PL which (apparently) uses two tubes running at lower gain for each stage. Interestingly, the Mini claims more overall gain than the PL, though still within a comfortable level for a single 12AU7 per channel. But the PL claims a much quieter circuit than the Mini, probably due to using two tubes for gain stages instead of one. In this case each tube is closer to its ideal operating point and not pushed as close to the limits of the tube. Is the PL's gain enough for your system? You will be running the PL at a higher position on the volume pot than you probably will with the Mini. If you don't mind the look of where the pot sits, running the pot at a higher position will amount to less (lower resistance) of the pot being in the signal path. Not much of a deal since we don't know the resistance of the pot in either pre amp. Of, course, if your power amp has a high sensitivity spec (actually a low number like 0.75 volt instead of 1.5 volt)), the PL will probably be enough when paired with a typical CD player. Some phono cartridges might need more gain than the circuit of the PL provides. This would, of course, also depend on the gain of the phono section. Both pre amps have rather high output impedances with the PL being substantially higher than the Mini. Personally I would prefer to see an output impedance around 500-600 Ohms or lower. Cables will probably affect the sound quality of both pre amps and cable runs should to be as short as possible for both units. I would not suggest running dual mono power amps placed across the room (by the speakers) with either of these two units. Instead of debating whether the pre amp is dual mono, you would prefer to know something about the quality of each transformer. To say a pre amp uses a toriod is not enough information; though an equivalent quality toroid will be a better choice than a simple box transformer. However, given the choice, a single power supply transformer separated by an umbilical cord would probably be even better. None the less, I give the nod to the toroids if everything else (current capacity of the transformers [notice the PL runs at a much higher power consumption than the Mini]) is equal. Dual mono is not an outstanding feature in a pre amp since the unit deals with such low levels of current. There aren't the same issues of crosstalk in a pre amp as you will face in a power amp. Signal paths are much easier to separate in a pre amp and the issue of crosstalk is only usually relevant to a phono section. There are no channel separation or crosstalk specs at various frequencies provided and that would be what you would want to know about both pre amps to make a minimally fair comparison. But, again dual mono is theoretically better than a shared power supply if all parts are of equal quality. The PL looks like it uses Nichicon and Elna caps and this would indicate a bit more expense (and perceived quality) than the Mini's choice of components. Which set of caps are needed to do the job is still the issue and lower quality caps of higher value will often be the better choice in a power supply. More small caps will give a different sound than fewer bigger caps and you might prefer one sound while buying the other. Chokes in the PL power supply are definitely impressive but there are lots of components in the PL beyond the tube count. Here the simplicity of the Mini allows a simlified ground plane which always lets components operate with more finesse and usually moer able to retrieve better low level detail and micro dynamics. More so than a pre amp with choke regulation? That I don't know. What about macro dynamics? Usually the better power supply wins that one. Actually, if you can decide which pre amp has the better power supply, that's the one I would suggest buying. As usual, there is more than one way to build a good power supply. The Alps Blue Velvet in the PL is a preferred pot among DIY constructors and mid priced high end manufacturers. It's not expensive by comparison to some of the best but it feels and sounds quite good. The Mini doesn't list a part source for their pot so we are left to wonder whether what they use is better, worse or the same as the Alps control, though the Mini does appear to use a pot and not a stepped ladder type control or an autoformer. The dual mono design of the PL is somewhat mitigated by the single volume control where the ground planes have the potential for crosstalk. Better would be two separate volume controls and no balance pot (another source for signals to mix), though that arrangement is far less convenient than a single stereo pot. The quality of the stock tubes would be an issue though this can easily be changed by the user. All the tubes used in both pre amps are easily available as new or NOS. As I said earlier, the 12 series tubes are well known for their "sweetness" with the 12AX7 being the ubiquitous pre amp tube of classic designs. I would expect both of these pre amps to have a clean, open sound with a touch of midrange allure and a slightly soft top end. They shouldn't be extremely analytical but not overly colored either. Caramel used to be the description for the generic 12AX7 sound. So, the case can be made for either pre amp. If I had to pick from the information I have available on the two web pages, I would likely decide based on how long I wanted to own each pre amp. If I thought I wanted to play with the minimalist Mini, I would not expect to hold onto the pre amp for more than a few years. My general feeling is there is too much being asked of the few components to have an extremely reliable unit over the long haul. But that is based on simply looking at the pictures and reading the p00p. The Mini probably runs much cooler overall than the PL and that leads to more reliable components. The PL is undoubtedly over built in the same "tradition" of the Mac pre amps from the 1960's. (Actually the Mini reminds me more of a Marantz 7C with fewer parts while the PL reminds me somewhat of the Mac C22. Both are classic designs.) If I were looking for a pre amp I might own for a decade, I would choose the PL after only looking at the web page. http://www.passlabs.com/downloads/articles/powersupply.pdf#search='power%20supply%20capacitors' http://www.tnt-audio.com/clinica/ssps1_e.html These two articles mostly deal with power supplies for solid state power amplifiers but the general information is worth knowing. In a way you can think of a pre amp as just a small power amplifier. Gain is gain and it starts with the power supply. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1269 Registered: Dec-04 | Absolutly SMOKING information, Jan, very much appreciated. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7519 Registered: May-04 | Regarding tube life in a pre amp, you should expect most signal tubes to last five to seven years with normal use. I would expect the PL to have longer tube life than the Mini since the PL appears to run the tubes more conservatively. The PL might extend the tube life to ten years. Swapping the rectifier tubes will not give much change in sound, and spending extra for a NOS tube here would probably be too much money for too little gain. Unless you have money to burn putting $50@ 12AX7/12AU7's in a line stage pre amp under $2,500 is, in my opinion, rather ridiculous. The extra money might be justified if you were running a very low output MC cartridge into a phono stage, but certainly not for line stage use. Everyone has their own opinion but I find the price of most NOS tubes to be outrageous compared to what is available if you shop well. There are some very good current production 12AX7's for around $12-15@ that should work well in a line stage. |
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Bronze Member Username: PaulfolbrechtPost Number: 60 Registered: Dec-05 | I second that, Nuck - smoking! You've pretty much echoed my thoughts on the circuit simplicity with a lot added. I hadn't considered component longevity being an issue. I also hadn't considered multiple tubes resulting in lower noise due to lower levels. Obviously very important! And the PL gear is indeed very quiet. It does have plenty of gain. Especially b/c I'm driving 70W blocks. Half-volume is LOUD - as loud as I EVER use. I'd noted the high gain of the MNM - I think that's because their matching power amp is only 8WPC As for tube rolling - I hadn't bought anything. The prices were too much, especially considering two each au7 and ax7 in the 7 monoblocks as well!! Sorting out the minor BS in the industry can be a bit of a trick, of course. Never having heard NOS tubes myself, I don't know how much difference there might be. I don't know if I need to play around with preamps at all. :-} Well, I'd like to, but maybe only if I can find good used stuff. Yout did hit the PL's sound on the head, as well. The mids are the strong point - deep and velvety. I have another one for you to do... I think we would all love to hear this. Would you mind comparing the PL 7 monoblock with the AES Six Pac? Here are some links: http://www.upscaleaudio.com/product.asp?itemid=553&catid=36 http://www.upscaleaudio.com/product.asp?itemid=26&catid=29 What I really like about the SP (on paper) is the ability to switch out negative feedback altogether and also the smaller complement of driver tubes (2). But, as I've just learned, that may not really be any sort of "advantage" at all. Thanks for the Tubology 101. And I do apologize about the late tuition check. Next week, I swear. Paul |
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Silver Member Username: Two_centsPost Number: 694 Registered: Feb-04 | First of all, the stock tubes on the PL amps aren't that bad. It'd be worthwhile to get used to the sound of the amp with the stock tubes before rolling in new tubes. If you want to try new tubes, replacing the 12AX7's on the PL amp probably makes the biggest difference in sound quality, with the right tubes. I've tried Sylvanias in my PL2 which gave an incremental improvement and NOS RCA 12AX7A's, which gives a noticeably more solid presentation of music. They are reasonably priced, unlike NOS Mullards and Telefunkens. I was considering the AES Six Pac also, but the thought of replacing 12 output tubes every couple of years wasn't appealing. |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1285 Registered: Dec-04 | 2c, are you running any global feedback via the shielded cable, or stand alone? I have seen some funky global setups via the shilded, with .3, .4 % |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 7523 Registered: May-04 | I'm not the person to ask for a comparison of the two amplifiers you've suggested. I use two forty year old amplifiers without even so much as an on/off switch. They take 6L6's or KT66's and they get unplugged from the surge protectors when I need them to be off. The idea of using pentodes as triodes and switching NFB in and out of the circuit makes no sense to me. I understand there are listeners who would prefer to hear such things, and tinker with VTA and so forth but they are not my cup of tea and I almost always dreaded having to discuss such things with my clients. My opinion of all these things is they play into the marketing and mysticism that makes audiophiles more interested in the equipment than the music. Like keeping a Triumph TR3 that runs, the proud owner is allowed into some exclusive fraternity that only permits the most elite and privileged souls on board. Don't get me wrong, I believe in tweaking and I think many of the changes you can adapt to most commercial designs can be beneficial. That is, if you know where you are aiming the arrow. If you instead go hunting with a shotgun, you will kill much more than you can eat. All that said, I do, however, have a lot of respect for Had's ability to design and produce a good sounding, affordable tube amplifier built in the US. It is something I would consider in my assessment of each amplifier. Beyond that you should consider what is the essential sound of each amplifier and what are the advantages and disadvantages in using the product. Self bias vs. adjustable bias is one example. Some people like the ability to play with bias to adjust the sound one more notch up or down. Others like to play music when they switch the system on; as in the ol' one button stuff that Larry R. wishes was still around. With either amplifier it makes sense to spend the extra $10 per pair to buy matched sets of output tubes so there is no real advantage to one type of bias arrangement in that regard. Convenience vs. tweaking is the issue I see. (http://www.tubedepot.com/whisbipo.html) KT88's do not sound exactly like EL34's. ("The NOS 12BZ7 was a final revision to the design, replacing a 6922 and allowing, in Had's words, for 'a much greater swing into the EL34 output tubes with a lower distortion value.' Terrific! I'm a bit surprised he didn't allow you to switch back and forth to confirm this too.) You can run EL34's in the PL but then why buy the KT88 amplifier? Just so you can play with output tubes? Once again the curiosity of hearing and knowing (and sharing with your closest friends) that little bit of magically descriptive phrasing which reviewers hold above our heads as a password allowing back door access to the Speakeasy and the carrot which keeps us buying more stuff is a strong lure to play with the amplifier instead of listening to music. What if a disc doesn't sound just right? Would it have more soundstage depth if you had the KT88's in the amp instead of the 6L6's? Maybe the "Winged C's" in place of the JJ's would be the ticket? There is a member on another thread who is chomping at the bit to hear the "tube magic" that he has read so much about. While I would never suggest he not listen to tubes, it seems impossible to convey to someone with this bug in their ear that the magic should be tubes which have no sound at all. Searching for the colorations that occur with each little tweak of a tube amplifier has become the new game for well heeled audiophiles to play. It is the audiophile version of having a wine from the early harvest on the private estate's South acreage rather than the later bottling which suffered from too much moisture and not enough long cool nights due to the more acidic Northern exposure. While the magazines once espoused neutrality above all else, they now play with the concept of "magic" coming from each and every different bottle or can. Ahem. Once you accept the qualities of a tube amplifier as something you want, you accept the downsides of tubes also. Tubes are not simple devices that you plug and play forever. Tubes are microphonic, tubes produce heat and tubes wear out. That is to name just a few disadvantages. No matter how well an amplifier is designed, a bit of microphonics in the loop and you will be wishing you could instead just live with 10dB of NFB. Heat is a relative matter and everyone lives with it when you use tube power amplifiers. (The PL's probably run more conservatively than the Had design which will produce less heat therefore extending tube life.) But you will have to replace tubes at some point if you keep the amplifiers. The cost of doing this should be a factor in your buying decision just as the cost of maintenance on a mid life crisis sports car should be taken into consideration before you give up the family sedan. Replacing the eight output tubes and fourteen input tubes on my two Mac amplifiers is a trifle painful but worth the effort every five years or so. I knew that when I bought them. And I get a new amplifier each time I buy tubes. It's like saving up to go to Vestri Chocolatiers; lots o' fun even if it dents the wallet! (Hint, the chocolates with the pinch of cayene are my favorites in case anyone is wondering what to get me for Xmas.) I saw a review of the Denon AVR-4806 in which the receiver was described as attempting to be "pluripotent". What a wonderful word to describe what some audio pieces want to achieve. They will never be fixed in development and always enjoy plasticity of function and design. What a concept! My only question would be; does it sound good? |
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Bronze Member Username: PaulfolbrechtPost Number: 61 Registered: Dec-05 | I've got well over 200 hours on the equipment so I do know it pretty well. Thanks for the tips. The ohter thing about the tube rolling, which I've alluded to, is that the power amps also have their own driver tubes (4 per block!) which would also have to be changed. I now see the benefits to multiple tubes (running them cooler, etc.) but that's a lot of tubes. As for the 12 on the Pacs, that's not much worse than the 8 on the PL blocks I have now. Also looking at Manley Labs. I auditioned by current speakers with Stingrays but those are too much for me. But used Mahis might be in my future at some point. Paul |
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Bronze Member Username: WhatzzzupppMontreal, Quebec Canada Post Number: 27 Registered: Nov-05 | hi i have the fortec star i lost all the channels can someone help me please can u tell me how 2 download the new program thnx in advance |
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Bronze Member Username: PaulfolbrechtPost Number: 62 Registered: Dec-05 | Hey Jan, Appreciate your comments. Points taken. You're right that I'm a tweaker, but mostly just CURIOUS as to WHAT SOUND I WILL ULTIMATELY PREFER. I agree that neutrality is the goal, but that's only the tonal aspect; surely there are many more differences between gear & tube types? The PL gear has in no way disappointed me. You recall that this started when I was startled by the different (and in SOME ways probably better) sound of another preamp; now, I'm in a mode, for better or worse, where I kinda just want to hear everything in terms of basic designs within my price range and be satisfied that I have what I like best. What I hate is that I have to buy stuff (for the most part) to DO this.. that is why I am becoming set on sticking to the used market. Then I get my $ out of anything I don't like, or close (or maybe a bit more). I hear you on getting taken up in the techie crap, but rest assured I am most certainly still listening to and greatly enjoying a lot of MUSIC. :-} More than in any other period in my life, really. (I have no TV and don't miss it. I mean, I have a TV for movies, but no cable/antenna hookup. It's on once or twice a week. When I'm at home, I'm listening.) Wallowing in pluripotenence, Paul |
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Gold Member Username: NuckParkhill, Ontario Canada Post Number: 1293 Registered: Dec-04 | Jan, you 'convenience vs. tweaking' line strikes quite a chord here. Does not the convenience of function negate the beauty of form sometimes? Should'nt the linearity of the function dictate the future of the form? I am old school, solid state, but the future seems pre-decided, as newer/better/faster/bigger stuff comes online. Or am I just too old? |
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Silver Member Username: Two_centsPost Number: 696 Registered: Feb-04 | "You can run EL34's in the PL but then why buy the KT88 amplifier?" The problem is that some music (chamber music, small combo jazz and vocals) sound better with EL34s and some music (rock and large orchestral works) sound better with KT88s, but there is no easy way to switch tubes, granted the differences between the tubes aren't huge. I pretty much stay with the EL34s, because the audio quality is more critical for me for the smaller scale stuff. The rest of Jan's post puts the techie audiophile busibodiness into an appropriate context. Paul, I'm not running any global feedback setups. I think the six pacs are kind of gimmicky in that regard. I'll be interested in reading more about your audio adventures. What is it Stephen Stills sang, "Love the one you're with"? |
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