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New member Username: MongoTucson, AZ USA Post Number: 2 Registered: Apr-04 | I have read some forum posters declaring how bad the DPR 1001 must sound based on various rationalizations, but I have had mine for several weeks and I couldn't be happier with the audio quality. The primary reason I got the DPR 1001 was to upgrade to surround sound home theater from my old 2.0 stereo AV receiver, and I wanted to take advantage of the digital outputs of recently acquired source components. Reviews I read on the Web reported satisfaction with the audio quality, and I found myself enthralled with the digital audio technology. When I first got the DPR, I hooked it up to my old stereo speakers, and I was amazed at how much better my old speakers sounded. Of course, I upgraded to a new surround-sound speaker system, which sounds even better. My first test of the system was the DVD movie, Matrix:Revolutions, and it just blew me away with how wonderful it sounded. My favorite audio CDs sounded better than I had ever heard them before. I want to respond to forum remarks about how IC amplifiers just sound so much worse than "transistor" amplifiers. Well, guess what the main component of an Integrated Circuit is - transistors! So, an IC amplifier IS a transistor amplifier. Then, this forum poster went on to cite his evidence: a review from 15 years ago. Sure, 15 years ago the state of the art in IC amplifiers was probably behind that of discreet transistor amplifiers. But ICs are usually aimed at the mass market, not the high-end audiophile market, so the IC amplifiers probably had adequate performance for the low- to medium-end markets they were intended for. Now, the state of the art in IC amplifiers has greatly advanced, and the DPR has direct digital amplifiers using DDX ICs from Apogee Inc. Apogee DDX implements an improved version of Class-D amplification called Filterless Class-D, along with sophisticated digital signal processing to eliminate the analog negative feedback normally used with Class-D amplifiers, thus eliminates any Transient InterModulation distortion. Comparing the DPR spec sheet with that of a similar power HK, such as the AVR 330, the AVR THD rating is definitely better (0.07% versus 0.19% for the DPR), but a more significant specification is TIM distortion ("Unmeasurable" for the AVR versus "None" for the DPR). Now the analog transistor amplifiers in the HK AVRs specifications indicate to me that a lot of attention was paid to minimizing TIM, but any negative feedback amplifier will have some TIM. The problem is that human hearing is much more sensitive to TIM than to THD, while THD is much easier to measure than TIM. So, I don't think the THD difference will be audible, while the TIM difference likely will. Except for the power amplifier, the H/K AVR and the DPR are pretty much the same: digital. This is how "Dolby Digital" and other surround-sound modes are accomplished, that is, through Digital Signal Processing, just like in your PC. Where the AVR uses a conventional line-level analog-to-digital converter to drive an analog audio power amplifier, the DPR uses DDX to go directly from the digital data stream to the analog speaker output without any analog amplification or feedback. But the technology in the DPR 1001 (in the form of Apogee DDX-4100A ICs) is now about two years old, so the DPR 1001 is being discontinued to make way for the new DPR 1005 and DPR 2005, which offer higher output power, lower distortion, and greater signal-to-noise ratio. Not because HK is abandoning the DPR line as some have alluded. I am also glad that HK went whole-hog to digital technology with the incorporation of a switch-mode power supply, eliminating the hot and heavy power transformers typical of "linear" power supplies. Personally, I prefer the size and styling of the DPR 1001 over that of the DPR 1005 and 2005, which seem to be styled to resemble the current AVR X30 line. Bottom line: for the $500 I paid for it, I think I got a great deal. |
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Bronze Member Username: BluesPost Number: 11 Registered: Mar-04 | Mongo, Nice post. I've auditioned the 1001 and found the sound to be just as clean as the AVRs. IMO digital technology is here to stay. The difference in THD (for the H/K receivers you mentioned)can only be heard by a dog. Others on here will whole heartedly disagree. Heck, why would you want something that weighs almost 50 lbs when you could have similar performace in a 23lb receiver that runs cooler? I'm a beleiver, but time will tell. Good luck with your new toy. By the way. What speakers are you pairing it up with? |
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New member Username: MongoTucson, AZ USA Post Number: 4 Registered: Apr-04 | Back when I was a poor starving college student, I worked part time as a salesman at a well-known consumer electronics franchise selling among other things HiFi/Stereo. I had the opportunity to audition many speakers, and the ones that impressed me the most were the Cerwin-Vegas. Ever since, I have wanted to own Cerwin-Vegas. So when I decided I had to upgrade my home theater, and could afford some decent new speakers, I looked at the Cerwin-Vega web site and decided to base a system on their 15" powered subwoofer, the HT-S15. Since a subwoofer would take care of the bass, I figured I only needed bookshelf size speakers for the rest of the system: Cerwin-Vega CLSC-6C center and CLSC-6 for L/R front (6" 2-way). Typically for C-Vs, they are very efficient, so I can make the most out of the 50 Watts from the DPR 1001. I went a little cheap for the surround and multi-room speakers with the JBL E10 (but mainly because they are wall-mounted). They are not quite as efficient as the C-Vs, but work well in my system and the DPR lets me balance the sound levels. The more I play with the DPR 1001, the more amazed I am. When I first started with home audio equipment, everything was analog, and noise was typical: hiss, hum, wow, flutter, rumble, etc. Listening to a CD with an optical-digital cable is amazing to me because there is no noise! Even with headphones, when I turn the volume all the way down, or pause the play and turn the volume all the way up, and there is no noise! This is audio paradise for me. |
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Bronze Member Username: LandrovalPost Number: 64 Registered: Feb-04 | If you like Cerwin-Wegas, I'm not too willing to believe anything you say about the DPR. Although I think digital amplifiers are nice and will become a lot more popular in the future, mostly because of lower cost and smaller size, but probably also because of better sound quality in some cases. |
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Silver Member Username: GeekboyNewport, RI United States Post Number: 253 Registered: Dec-03 | All: I don't think the majority of people hate the DPR or what it stands for. It was merely a pick at "new technology" and who would be the first people to accept it. I jumped on the DVD wagon too early myself (1997)... and had to suffer those pitfalls. Continuous improvements in Class-D amplification is just the way it is. The makes of these receivers will make them better and better over time, no doubt. They will become the mainstream amplification in consumer devices no doubt. Besides, Class-D amplifiers use much less power and give off much less heat. They will become popular as price comes down and it becomes mainstream. For now, they are just "new" technology to many, and most, like you, have purchased them as the priced has been rolled down to reasonable levels. |
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New member Username: MongoTucson, AZ USA Post Number: 10 Registered: Apr-04 | landroval, I am disturbed by your apparent disdain for anything made by Cerwin-Vega. Now, I realized this is not the most appropriate forum for discussing speakers, so I will try to keep this short. I have done some searching, and I find your disdain for Cerwin-Vega is not uncommon. But the few actual examples of unpleasant experiences with Cerwin-Vega speakers were with models very different from what I have. The Cerwin-Vega company has a diverse product line, with professional speakers for concerts, theaters and studios, plus car audio speakers, in addition to home audio speakers. Even their home audio speakers are offered in several lines. Most of the reviews I have found for C-V home audio speakers have been examples from their E-series. I assume the "E" stands for economy. Cerwin-Vega, like any successful business, responds to the marketplace. There is a market for inexpensive speakers, and the E-series caters to this market where buyers are willing to compromise sound quality for a lower price. The reviews of the E-series speakers I have been found are generally favorable, but mixed. But, I do not have E-series speakers. I have Classic-series speakers. The specifications and descriptions of these gave me reason to believe that they will have superior sound quality over the E-series, and be comparable with the C-V home audio speakers I auditioned and was impressed with some years ago. My experience with them in my living room has been most pleasant. The main standard for comparison I use is my Koss headphones, and I can't hear any significant coloration or distortion from the speakers in comparison with the headphones. You did catch me on one thing, that I did not audition many speakers before I bought these C-Vs, so I can't say much about how they sound compared to other speakers that may currently be popular and fashionable. But, isn't this also true for you? Remember the thread here: The proof is in the listening. Have you actually listened to the C-V speakers I have and can really compare their sound quality with that of other makes and models? |
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Unregistered guest | Mongo, your comments on IC's are right on, for the most part. A few problems with IC's are the fact that they are bandwith limiting devices and more importanly, current limiting devices. Thats why no reputable amplifier manufacturer uses IC outputs. Heck, even my CAR audio head unit is IC free. One thing on your new digital amp: keep it on 24/7/365. Digital devices run very cool compared to transitor amps and take much longer to warm up. That includes cd players, dvd players and new digital amps. Bet it sounds noticeably better when left on for a few days to warm up. try it and let me know. |
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Bronze Member Username: MongoTucson, AZ USA Post Number: 15 Registered: Apr-04 | mauimusicman, You seem to have missed my point: IC amplifiers ARE transistor amplifiers. Every transistor amplifier has a bandwidth limitation and a current limitation, regardless of whether it is discreet or integrated. Actually, the widest bandwidth amplifiers I have used as a professional electronics engineer have been IC amplifiers with bandwidth over 1000 MHz. I will grant you that discreet transistors are available with higher current and power ratings than what I can find in an IC amplifier, but these are much higher than what we need for a home audio amplifier. The only audio equipment I have used which needed to warm-up were built with vacuum tubes. A well designed solid state amplifier will have temperature margins, temperature compensation and feedback so that performance is within specification as long as it doesn't get too hot or cold. The direct digital amplifier technology in the Apogee DDX used by H/K in the DPR 1001 makes feedback and temperature compensation irrelevant. The bottom line in my living room is that the DPR 1001 sounds wonderful cold, and it sounds wonderful after running for many hours. For further reading, I highly recommend the web page in the following link, This addresses some popular misconceptions about audio electronics, although it does not directly discuss audio warm-up. http://www.ethanwiner.com/myths.html |
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Unregistered guest | Mongo, while I appreciate your enthusiasm for digital devices, you may be a tad over board. I agree that all solid state amps are bandwith limited. Mine has a freq response of .5 hz to 500khz. This is hardly "limited" It also swings 80 amp's of current. And i'll pay you the national deficit for every IC you find inside my amp. The jury is still out on digital amps. I'm happy with my solid state amp. Very happy. Still say your digital amp will sound better after being on 3 to 4 days than it will starting cold. Physics dictates it will, anyway. Wish I could find a way to bypass my DVD players "auto power off" feature and leave it on 24/7 My CD player sounds WAY better if I leave it on constantly. |
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Unregistered guest | Mongo, it seems you did some homework on the H/K product. Good job. Education is essential when chosing audio components. You should do the same thing with speakers. Cerwin Vega speakers are typically advertised to young, rock/metal music lovers. They use massive bass drivers 12 to 15" which are hard to start, and equally hard to stop, causing lots of "ringing" They use cheap foam surrounds which rot during normal use. They use paper drivers in most of their systems. We all know what happens to paper as it ages. Their tweeters "beam" and the midrange is "honky" Listen to some newer designs, like Paradigm, Sonus Faber, GMA, Quad, etc to hear what a good speaker sounds like. Then compare them side by side to C.V's. Your smart enough to take it from there. Good listening. |
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Bronze Member Username: MongoTucson, AZ USA Post Number: 21 Registered: Apr-04 | mauimusicman, I appreciate your patience with me, and the reasonableness of your arguments. I aspire to be a reasonable man, and that requires willingness to learn. It sounds like you have an awesome amplifier there. I didn't mean to sound like I thought discreet amplifiers couldn't have excellent performance, because I know they can. Maybe I am raving about the DPR so much because I am amazed that a digital device can sound as good as this one does, especially since I only paid $499 for it. I have considered discreet transistor amplifiers like yours, but if I decided to have one, I would likely build the one I learned about in the Audio Engineering class I took that was taught by Dr. W. Marshall Leach at Georgia Tech: http://users.ece.gatech.edu/~mleach/ Actually, when I took this course, I also took a course on analog integrated circuits, and I asked Dr. Leach why he did not use an IC for the input stages of the amplifier. His answer at the time struck me as very reasonable: He could get discreet transistors with much better noise performance than he could find in an IC, and he could also better control the operating points and stage gains and thus optimize distortion performance. Since then, better ICs have become available, and as a personal experiment I built an amplifier from my own design. This was based on the LM391 IC from National Semiconductor, which has a high-impedance input circuit and is intended to drive discreet bipolar power transistors for the output. I designed a circuit to use the LM391 to drive power MOSFET transistors. The thought here was that MOSFETs would produce less IM distortion than bipolar transistors. I only built one prototype, and tested the THD and IM distortion. I don't remember the numbers anymore, but I remember being quite pleased with the performance, and my audiophile friend who performed the testing was quite impressed. So I know from experience that an amplifier built around an IC can have excellent performance. Certainly, there are discreet transistor amplifiers which have better performance, but this was good enough for me. I still don't get how a lengthy warm up period will benefit a digital amplifier. I can certainly see how it would benefit a vacuum tube amplifier. To a lesser extent, I can imagine how a poorly designed bipolar transistor amplifier would benefit from warmup, because bipolar transistors exhibit an increase in gain as temperature increases, which can lead to thermal runaway (overheating and destruction) if not compensated for. A poor thermal compensation design can allow the bias point to shift with temperature, and if optimized for normal operating temperature (i.e., after warm-up), the bias point cold will be inadequate resulting in crossover distortion. A good thermal compensation design will prevent this. Also, a MOSFET output amplifier, and especially a digital amplifier, will not have this problem. The only other physics that I can see that would apply here is the thermal noise phenomenon: V^2=4kTRB. This says that noise increases with temperature. In communications, I have seen amplifiers cooled cryogenically to reduce this noise. This tells me that high temperature is generally a bad thing. So, what physics were you referring to? My goal for my loudspeaker selection was to get acceptable performance at a reasonable price. I don't want to go into too much detail in this forum since I started a thread in the speaker forum on Cerwin-Vega speakers, which I encourage you to take a look at. The essence is that Cerwin-Vega builds a wide variety of speakers, and I am sure that everything you said about CV speakers is true for some models. But I haven't seen any specific criticism of their Classic line of speakers, which I have. These are their high-end home audio speakers, and from the description and specifications should have higher quality sound than other CV home audio model series. Now, you did catch me on not auditioning any of the competition, and in buying these speakers without making my own listening tests I ran the risk of getting awful sounding speakers. But these speakers are relatively cheap! The CLSC-6 (6" 2-way bookshelf) is only $99 each, the CLSC-6C center was $169, and the HT-S15 subwoofer only $299. I only spent about $700 on the CV speakers, so I figured I could take the risk. I found that the CLSC-6 works well with the HT-S15. I have read that the HT-S15 sounds poor above 70Hz, but all I care about for a subwoofer is below 70Hz anyway Since the CLSC-6 is specified down to 50Hz, I set the active crossover frequency to 60Hz in the DPR 1001, and it sounds great. So, I apologize if I come off sounding like this is the greatest sounding home audio system in the world, and I admit that I don't think it is. My assertion is that for the money I paid, it sounds really really good, and the challenge I make is to describe a better system for less money (about $1500). My system sounds much better than what I had before, so maybe I will educate my ears with this and one day be able to appreciate an even better system, something like what you have been describing. |
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Unregistered guest | Monggo, nice post. I've been doing home audio for over 30 years. During that span, i've learned quite a lot. I've had the pleasure of working alongside some of the audio world's finest designers (Roy Johnson of Green Mountain Audio; Jeff Rowland of Rowland Research) They have taught me so much. I can tell you this without a doubt....in speakers, much of what makes one sound "right" is phase. Most speakers fail miserably in this area. In fact, most designers won't even attempt a time/phase aligned system because the math is too difficult(The most difficult in all of physics) so they settle for the scope data and the computer based cabinets. Once you've heard a TRUE time/phase aligned speaker, nothing else will suffice. You'll hear the crossover and the phase problems in every speaker you listen to after that. Good luck with your speaker journey. As far as the digital devices being kept on 24/7/365, one need look no farther than ANY electronic device that plays music. Amplifiers are never tested prior to a 1/3 hour pre-conditioning warm up period. It's a known fact amp's sound better after warm up periods. Digital devices have little heat passing thru them, therefore it takes MUCH longer to get them up to "proper operating temperatures" Try it. You will hear a difference. |