Advise: Static Through Speakers When Volume Turned to Lowes Setting?
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New member Username: LovegasolineNYC Post Number: 3 Registered: Jul-05 | I'm a newbie ready to start my first budget system. I'm wondering if someone can give me a quick and dirty answer ASAP. I found a local guy selling an older (mid 1980's) Yamaha integrated amp model A-700. I do not know what to check for to inspect the unit, but another poster suggested that I check that the switches all work, make certain the levels right/left channel are equal, and to make certain there is no popping of crackling sound when turning any of the knobs. I emailed the seller with the info & this is what he wrote back:: "I have the amp hooked up right now to a CD player. Feel free to bring a CD to listen to if you want. I also have a bunch, mostly jazz. I tried all the things that your advice talked about, and the only thing I noticed is that when turning the volume all the way down to silence, there's some slight static that comes through the speakers. This happens when the volume is nearly all the way to the left. Other than that I didn't notice anything." Just going off the cuff from his description, is that static indicative of a potential problem that I should be concerned about, or is it just some of speaker hiss or something minor? If you an write back ASAP I'd appreciate it, I'd like to go by tonight and listen/buy it. Thanks! PS: I posted this here (and on the integrated amp section, figured it'd get more replies here) |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 4646 Registered: May-04 | This is probably a dirty volume control that can be cleaned without too much trouble. It could be a volume control that can no longer be cleaned to keep it working for more than a short period of time and will need to be replaced. Only a technician can tell you which it is. With used equipment you sometimes cannot tell what the problems are without some extensive testing. 90% of the time I would take the chance that the problems are minor. The Yamahas from that time period were generally reliable but this is a problem of age not reliability. Mechanical parts eventually wear out. If this problem only occurs at low volume, it may not even affect your listening. You pays your money and you takes your chances. |
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New member Username: LovegasolineNYC Post Number: 4 Registered: Jul-05 | Jan, That was a well balanced answer and very useful to me. I didn't make it out to pick up the amp today; tomorrow evening I'll go and if the hiss isn't there at the other volume levels, I'll take my chances with the unit. Could a grounding issue manifest itself in a static sound (I understand the overuling caveat that without doing diagnostic testing it would be hard to get at the root cause)? When buying an older, used, untested unit like this what general initial maintenance is recommended when getting it home? Open the case and clean off 20 years of accumulated dust? Is there a good simple method of cleaning the switches/control knobs? Are there any other basic tips that I can apply upon taking ownership that you'd care to share? I've done some very basic electronic circuit building/troubleshooting (novice and not super sophisticated) and I generally feel confortable mechanically..so if it's not TOO involved...I'd love to hear suggestions Thank you again for the informative reply. Cheers, Neal |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 4658 Registered: May-04 | Grounding problems will either result in 60Hz hum being present along with the signal or no signal at all. I would buy a bottle of Pro Gold cleaner http://www.audioadvisor.com/store/productdetail.asp?sku=CAIPG100LN and a package of long Qtip type cleaning tools. Pro Gold is also sold as a spray which is useful for cleaning pots and switches. Clean all contact surfaces you can see until no more oxidation comes off on the swab. Clean inside and outside of RCA's. Use the least amount of cleaner you can to do the job. More units come into a repair shop from an over zealous owner who has drenched the inside of their amp than from someone who was very judicious in the use of cleaner. Other than basic cleaning nothing else need to be done. Older units with mechanical switches should have the system torn down about once a year and given a cleaning as general maintenance. |
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New member Username: LovegasolineNYC Post Number: 5 Registered: Jul-05 | At $40 the Pro Gold is half the price of the amp (gah). Would a contact cleaner do it? Or another, less expensive solution you could recommend? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 4667 Registered: May-04 | Tuner cleaner will do the job. You can buy that at an electronic supply house or at Radio Shack. Pro Gold contains enough product to last the average consumer a lifetime of yearly maintenance and is considered the best product on the market. Consider the cost over more than the life of this amp. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 4679 Registered: May-04 | OK, a lifetime of yearly maintenance is a stretch. How about a lifetime of maintenance based on how often people actually do maintenance? How about, it has a fair amount of stuff in the bottle! |
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New member Username: LovegasolineNYC Post Number: 6 Registered: Jul-05 | Jan, My life, unfortunately, is already half over...so I bought a smaller size ;-). I asked for Tuner cleaner at RadioShack: they had no idea what I was talking about. I eventually poked around and found TV Tuner Cleaner...and next to it: the ProGold. They had a little pen-filled size of it ($10) and also had a small aerosol size of ProGold paired with "DeoxIT'"($14 for both) ....the latter claims to be a pre-cleaner to remove oxidation from contacts before treating with the ProGold... I bought the paired products. Is the DeoxIT useful also? I also bought the Yamaha A-700 this evening ($80). The seller could not reproduce the static when turning the Volume knob, which is a large knob. It looks like the volume knob was bumped at some point because it's slightly off axis to the amp's front panel and a slight bit loose....when I crack open the enclosure I'll have a look inside and see if anything is amiss. I've only had a cursory look over it and I'm listening to it as I write. Sounds fine. The only other problem that reveals itself now is the Loudness knob (which adjusts from: "Flat " then 1-10)...when turned between settings 9-10 (lowest setting) there is some crackling and break up through the speakers. Frankly, I'm not even sure what the Loudness function is for (as opposed to the volume)? I've got a Sony Diskman connected to the amp, which is hooked up to some very small speakers that were given to me when I helped a friend move recently (TEAC #LS-H100). I know nothing about these speakers & have found zippo on the web about them. However, having them sit on my bookshelf was the impetus for seeking out an amp and finally getting this show rolling!!! So they've already served their purpose as well as providing a big step up in sound from the boombox ( the latter my audio source for last 10 years). I have a cheap Gemini Turntable I bought new, many ( too many) years ago but never used. Plugged to the amp it plays...at the very least I can now play my LPs (albeit within the limits of the obviously mass market low-fi turntable). I haven't istened to my LPs for 10 years. Many transformations are happening in this small room in a very compressed time! I'll have many questions in the coming weeks as I begin my ascent into sound. I'm just a baby with regard to audio, a real novice. 15 years ago , when I started working and had a little cash in my pocket, I was eager to move up into better audio. At that time I purchased a book entitled, "Good Sound" by Laura Dearborn (copyright 1987) are you familiar with this? I read the book, researched a bit...but ended up buying a Mac Computer instead [$5,000+ at the time!]. So I never invested in audio equipment. Being a painter ensured that I'd be perpetually broke, and getting into climbing as a hobby sealed my fate. But I'm now prepared to make my first forays into a humble yet honorable budget system. Is there a good primer that reviews the current state of High Fidelity that covers where this book leaves off (1986 or 87) and that a layman can read and appreciate? I'm still a bit bewildered by all the Home Theater systems, the varieties of CD formats, let alone the digital file formats MP3 etc...and DVDs. My goal is a stereo sound system for playing CDs primarily....next step (ASAP) will be a speaker upgrade and a decent CD player (hopefully one that will play CDRW??) and a tuner. I suppose I should post my questions in the respective forums. I've been reading through many older posts and you seem to have a vast knowledge regarding the equipment and also a no-nonsense attitude regarding good sound/audio pleasure. I'm not at all certain where this amp positions itself in the hierarchy of HiFi gear....but I'm looking to buy components (used) that are at the same audio calibre as the amp and (/or a step up in anticipation of an inevitable upgrade down the road). I listen to a hodge-podge of music, mostly rock, but also a smattering of jazz, experimental, and also some classical....though the lion's share is rock. I live in an apartment, room is 12' x 20' x9', but I've got allot of stuff in here. Space is scarce, especially floor space. If, off the top of your IQ, you can offer any observations or recommendations, I'd be greatly appreciative. Thanks. Cheers, Neal |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 4694 Registered: May-04 | A Radio Shack employee is clueless? I'm shocked, absolutely shocked! What you bought is great. Use it according to the directions on the bottle and remember to be very sparing with its application. Use just enough to get the job done and no more. I don't have time to do explanations right now. I'll get back with you. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 4702 Registered: May-04 | Before I begin with any explanations, do you understand why "loudness" compensation exists on a pre amplifier and the Fletcher-Munson curves upon which loudness compensation theory is based? http://www.webervst.com/fm.htm |
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New member Username: LovegasolineNYC Post Number: 7 Registered: Jul-05 | Jan, I had a productive and informative day audio-wise. First, I got some 16g "speaker" wire @ Home Depot (I ordered 18g but the salesman erred and cut 16g). I got a longer RCA cable to integrate my DVD player into the system [inexpensive Philips consumer model, #DVP 642/37, a gift]. I dug back into the book I referenced above & I've been skimming it. Happened upon the section dealing with Loudness Controls & Fletcher-Munson curves. The book it actually extremely informative and highly readable. I also read the Setup/Operations/Care chapter. I just completed cleaning and maintenance on the Yamaha A-700 Int. Amp. She was surprisingly(!) clean inside, a very modest layer of dust as to be expected for a 20 yr old. I sprayed her with canned air and worked some of the more dusty sections with a soft fine sable brush. She really looks great inside. The wobbly Volume Knob turned out to be merely a loose nut that holds the pot to the panel. I hit all the RCA connectors, the fuse, the speaker connectors, even the grounding post and power plug with the DeoxIT followed by ProGold. Ditto for my RCA cables' connectors (for the CD player/DVD/Phono)..all el cheapo bottom dweller cables, btw. I also gently sprayed a short blast into all the control panel pots: Volume, Loudness, bass, etc.... and worked them back and forth several times. After I put the top of the enclosure back on I connected the speakers and input devices for a test run. The crackling from the Loudness control is completely GONE (whether it returns remains to be seen) , the Volume knob is secure & smooth as if it were oil dampened (also to be mentioned, no scratchiness or static on the Volume Control knob when turned to 'off/low' as the seller had observed). One thing I have noticed is that the MUTE switch , while lowering the volume dramatically, doesn't entirely void the amp of sound. This happens with or without the headphone plugged in. The volume is reduced about 85%, but sound still comes from the speakers. Is that common? Psychoacoustic Phenomenon. You beat me to the post on the Loudness Control. In fact, I'm trying it out now while neighbours sleep. The aforementioned book has a pretty good written explanation. The graph you referenced was very useful to visualise the phenomenon. "With music played at low volumes, we hear lower frequencies more weakly than higher ones and much more weakly then midrange-where the heart of the music lies. As the volume rises, the low tones & midrange are perceived as more equal in loudness & the ear becomes increasingly sensitive to the higher frequencies". From the description in my text, it appears music needs to be played back at a comparable volume to that which it was performed live, to hear it as it was originally performed. The music gets 'bass-shy' at lower 'background' listening levels, so the loudness control compensates...on mid-fi systems...because the extra curcuitry adds distortion and isn't dynamic with changes in playback frequency(?). The text also mentioned the imperative of listening to different speakers at IDENTICAL volumes when making a legit speaker comparison. Loudness Control: So, another pot is introduced into the circuit... Exactly HOW it functions electronically in the circuit, I'm ignorant of. My understanding of frequency needs more work. -Neal |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 4704 Registered: May-04 | In that generation of Yamaha products the mute button took the level down -20dB. So what you are hearing is correct. Continuosly variable loudness compensation is common to only a few brands of audio equipment. In the 1970's and '80's Yamaha and McIntosh used the concept but had somewhat different spins on how it should be used. I'll skip the McIntosh treatment unless you get a bit of luck with a used C32 pre amp. Yamaha suggested you set the volume control to what you thought would be a reasonably high level and leave it at that position. You would then use the loudness control to adjust overall "loudness" level for listening. Since this control continuously adjusts the amount of compensation, the idea was to always have the correct amount of boost at any loudness level. There are some flaws to this system, the most obvious being someone unfamiliar with the system turning the loudness compensation down while leaving the volume advanced and then turning on the amplifier. You can judge for yourself how useful the loudness compensation is on the Yamaha, my guess is as many people ignored the loudness compensation as used it. The Fletcher Munson curves are real and do occasionally require some boost to the top and bottom frequencies; but my experience has been the amount of compensation the Yamaha provides is rather too much in most cases and should only be used discretely at very low volumes. Ms. Dearborn is corerct in that most "audiophiles" dislike any additional, unneeded circuitry between the source and the speakers. Glad to hear the amp is in good shape. You hit all the right spots with the cleaners. The Yamaha should give you good performance for many years to come. Do your regular maintenance and let me know if you have other questions or if I missed something here. |
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New member Username: LovegasolineNYC Post Number: 9 Registered: Jul-05 | Jan, Thanks for the info and the encouragement...it's been a HUGE help. I do have just a few more basic questions regarding this amp. I have other questions regarding putting together a system, but I'll ask them in their respective forums. Interesting how the Loudness Control works. Your point about potential confusion in using it with a blasted Volume control is well taken. I'm still fiddling with it and haven't yet formed a preference of its usefullness for my needs. There are 3 other switches on the Yamaha I'm unfamiliar with and can't seem to find info on (the seller didn't have the manual that came with the amp,,,,a manual would be useful(!), I'd of never figured out the Loudness control on my own ). 1)SUBSONIC FILTER (all I could find is a mention on a do-it-yourself URL about certain low frequency distortions from warped records, potentially speaker damaging or sound degrading as the speaker trys to render the low bass...the filter removes these lower frequencies from becoming amplified downstream???) ...also: 2)AUTO CLASS A 3)DIRECT Are the 2 sets of speaker circuits for a quad system? I'm trying to get a sense of where the amp fits into the audio spectrum: How would you describe the coloration of the A-700? Warm, neutral, bright? I realise the subjective nature of audio, and listener's demands, but off the top of your head, do you have any recommendations for a used bookshelf speakers pair under $250...some general models that I can use as a starting point in comparing & shopping: for a 20'x12'x9' room with good mount of furniture, mostly rock, w/some jazz, experimental, & classical? Also, irregardless of price, what quality speakers is this amp capable of driving? I'm read that all the audio gear in a system should be roughly at the same quality level ....I have no way to calibrate where this amp fits in, can you provide some hints? RCA Cables: I've got the ubiquitous super cheap stuff included w/low-fi gear. When I upgrade speakers & input devices, will RCA cable upgrades be cost effective sonic improvements for the $$$ or not really at this level of audio quality? Oh yeah, do you know of any readable audio books that covers technology from about mid 1980's to the present? Cheers, Neal PS: were/are you a technician , designer, or salesman ? You have a lot of knowledge....of this one amp alone! |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 4744 Registered: May-04 | 1) Subsonic filter: Used to remove low frequency information before it enters the phono pre amp to conserve power supply voltage and current and allow the amplifier as a whole to operate in a more linear fashion. The subsonic filters all had different "knees" where the action of the filter would begin to affect the frequency response of the pre amp. Some did a good job and some were not much more than a button on the front of the amp. Take the grills off your speakers when playing a disc. If the woofers flutter or pump in and out while you're listening to a record, engage the subsonic filter. This should eliminate the movement in the woofers. If it doesn't affect the music, leave the filter engaged. A proper design for a subsonic filter should put its effect beneath 20Hz. If I remember correctly, the Yamahas all had decent filters. 2) Auto Class A: This is marketing BS. Ignore it. 3) Direct: This should eliminate the action of the tone controls from the pre amp's signal path. Technically this should simplify the signal path and result in somewhat better sound. Again, this is mostly marketing BS. I doubt you will hear any difference with the switch in or out other than not being able to use the tone controls. It was placed there when Yamaha was trying to suggest the buyer could achieve high end (i.e., no tone controls on the pre amp) sound and still have the convenience of having tone controls. Cake and eating come to mind. Speakers A and B are for two sets for speakers which will receive the same signal. They are wired in parallel and when adding a second set of speakers you must remember the overall impedance will drop. Two 8 Ohm pairs will result in a 4 Ohm net. This is not fixed as the overall impedance of a speaker system varies with frequency. Check Dearborn's book for more on impedance. The Yamahas of the period when your amp was built had changed their sound from the original Yamaha sound first brought into the US in the mid 1970's. The first series of Yamaha products were exceptional and their cost reflected their pedigree. Yamaha has consistently cheapened their products to open their markets. An original series Yamaha amp would have weighed over twice what your amp weighs. Your amp weighs much more than a contemporary Yamaha. The series your amp came from was still a specialty shop product. Yamaha had not made it to the mass market stores yet, but they would soon. As such, the sound is a bit thin compared to the better products of the day (Denon and Luxman were the preferred Japanese products of the time and Nakamichi and Kyocera had just introduced a series of receivers that were reasonably good for the money). It is somewhat bright when compared to the better products; which is mostly a result of the thinner sound on the bottom and mids. Overall the amp doesn't hold together well at its limits, which reflects the cost cutting in the power supply. Within it power restrictions, which should still get sufficiently loud, the amp is probably best described as slightly tilted up from nuetral and it doesn't aspire to plumb the depths of low frequency response. Attitudes regarding speakers vary with some listeners considering the speakers can be driven by virtually any amp with "reasonable" quality. Others consider the amp to be more important than the speakers and work with the "garbage in-garbage out" theory. The Yamaha is capable of driving most speakers you would consider putting with the amp. That is to say, it can drive $5,000 speakers if they are a relatively easy load. But, it will struggle with a small two way design with severe current requirements. I would say, if you belong to the first camp, nothing beyond $1500 would be reasonable. If you belong in the second " a speaker can only produce what it is fed" camp, stick with a decent two way that costs no more than around $600 per pair and add good stands or try the placement Mapleshade suggests for small speakers. http://www.mapleshaderecords.com/tweaks/bedrocks.php Ignore the product Mapleshade wants to sell you. Try a concrete paver with a cone under the front of the paver to tilt the speakers toward your listening position. Place two sheets of paper towel between the speaker and the paver. This position takes advantage of the pressure zone effect and will result in more extended bass response from a small speaker without the muddiness that often comes with placing a speaker on a stand, close to a wall. The speaker position works best with "near field" listening; your chair should be no more than around 7' from the speakers. I've had good luck with this placement and it eliminates the need for (and problems of ) speaker stands. Try the speakers both upright and on their side with the tweeters on the outside. Do not ignore the cone to tilt the speaker toward your listening position. http://search.yahoo.com/bin/search?p=wasp%20speaker%20placement I can't recommend specific products on the forum. There are too many options and you need to hear the speakers yourself, not take someone else's suggestions for what they prefer. Spend enough on the RCA cables to have decent construction. No sonic welds and plastic insulation on the plugs. Speaker cables make an improvement but usually not night and day. Kimber cables are a safe bet with the Yamaha as are a dozen other brands. The Home Depot extension cords make decent speaker cables for a very minimal investment. Read here: https://www.ecoustics.com/electronics/forum/home-audio/56618.html here: http://sound.westhost.com/site-map.htm and here: http://www.gcaudio.com/resources/howtos/index.html My experience covers a bit over 35 years in audio. I was a salesperson for 25 of that time though I have done many jobs in the audio field. |
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Gold Member Username: KeggerWarren, MICHIGAN Post Number: 2552 Registered: Dec-03 | Lovegasoline All of your advice from Jan has as usual been awsome! I work on gear quite often and deoxit is one of the best cleaners there is. (and yes cleaning the inside and all the switches is the first thing to be done) If you could get the service manual for your unit there are 2 things that should be checked/adjusted, dcoffset and bias. Now the bias you definatly need the manual for and if the unit sounds fine is probably within the ballpark. But the dcoffset can be checked without the manual and is a good general indicator of the health of the unit. The way you check this is with a voltmeter that reads in millivolts and hopefully has around a 200mv setting. 100mv or higher is to high, 50-99mv is acceptable but should be adjusted (if the amp has the capability) 25-49 is pretty good with 0-24 being excelent. what you are reading is both the positive and negative voltages in the unit and trying to get them equal which yes would read zero "in a perfect world". This voltage is a dc voltage being measured at the speaker outputs on the back of the unit with the input selector choosing a an input other than phono that has no unit plugged into it and no speakers that are attached. (make sure the meter is set to read dc volts not amps) If you don't have a meter or are not comfortable doing this check I would suggest that you take the unit to someone you know that could do this for a very small fea if not free! This dcoffset causes undo distortion and can be an indicator of the health of some of the caps/resistors/transistors/whatnot in the unit. Some units do have an adjustment for this and over time may need a little tweaking. Others that do not have this adjustment and if the reading is to high then the input transistors will more then likely need to be replaced with a matched pair. But if you do this test and the dcoffset is fairly low you can feel pretty comfortable that the unit is in pretty good shape. Not all units can you do this measurement on as in a MAC that has output tranformers the dc is blocked and the same goes for a cap coupled unit. But the vintage of your unit should have all these abilities. Take care! And glad to see another vintage unit being found and used as most of them are well built plus much better then what you would find today unless you spend an arm and a leg on something being built in todays market. |
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Bronze Member Username: LovegasolineNYC Post Number: 11 Registered: Jul-05 | Jan, Thank you for taking the time to provide explanations, background, and the additional references. Re-reading the Dearborn book and reading through the thread 'Descriptions and Definitions" has been very useful...I'm swimming in information true, but I'm also gaining a better theoretical/technical background as well as a more fleshed out sense of the big picture. The Yamaha amp background is very useful. I'll give me some general ground to stand on when communicating about the amp. I came upon a website 'Audio Classics' and poked around a bit. It's a fascinating site with photos & specs on vintage audio equipment. I looked at some of the 70's Yamaha amps and see what you mean...they were some big gals! Not bad looking either... Subsonic Filter: the speaker cone does flutter crazily and the filter eliminates it, without a negative effect on the music. Regarding the Mapleshade speaker placement: when you refer to a 'concrete paver' do you mean a cinderblock, flagstone (like used on garden paths), or something else? [I do have a some woodworking machinery here and if I do not have any on hand, I could probably get my hands on some thick hard maple slabs, and make something similar to the Mapleshade speaker blocks.] In any case I'll continue to experiment with speaker placement in here. Thanks again Jan! Neal |
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Bronze Member Username: LovegasolineNYC Post Number: 12 Registered: Jul-05 | KEGGER, Unfortunately I do not have a copy of the A-700, and do not know where I would begin to find one...I looked on the web but came up with nothing manual (therefor the bias test will have to wait). I'd like to have the manual in general to better understand the specs of the amp. I did perform the dcoffset test: Using a Fluke #77-III Multimeter, set to millivolts DC, I performed the test on the amp. The amp was powered up, all input devices were physically unplugged from the amp, all the speaker connections physically disconnected. The speaker selector switch on the amp was set to 'on', input switch set to Tape #1. I got a reading of +1.6 milliamps (actually, the meter read "-1.6") this is with the common (blk) probe on the (-) speaker output, and the red probe on the (+) output [and of course, blk probe to common input on meter, red probe to Voltage Input]. Does the data appear correct for the test? Thanks a bunch for the testing info. I've been reading through allot of past posts on the forum and come upon your contributions frequently...all part of my learning curve. The wealth of knowledge here has definitely inspired me to put forth the effort towards attaining better sound. Cheers, Neal |
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Gold Member Username: KeggerWarren, MICHIGAN Post Number: 2575 Registered: Dec-03 | Lovegasoline This has me puzzled a little bit. "got a reading of +1.6 milliamps (actually, the meter read "-1.6") this is with the common (blk) probe on the (-) speaker output, and the red probe on the (+) output [and of course, blk probe to common input on meter, red probe to Voltage Input]." You say milliamps not millivolts. I REPEAT DO NOT SET YOUR METER FOR AMPS AND THEN PUT THE LEADS ON YOUR SPEAKER OUTPUTS, SETTING YOUR METER TO AMPS IS A DEAD SHORT ACROSSS IT AND YOUR AMPLIFIERS SPEAKER TERMINALS WILL NOT LIKE THAT AND CAN CAUE VERY BAD THINGS. so hopefully you meant millivolts and had your meter set correctly and the terminals on the meter itself plugged into the right thing (volts not amps) also you say you got a reading of 1.6 (neg or pos does not matter) it sould be different for both channels like -1.6 on the left and maybe +12 on the right. so again make sure the meter is set to volts on a scale that will read millivolts, the leads on the meter are in the volts not amp plug ins and check both speaker terminals from the terminals you have selected as on by the amp. If you are not measuring from a terminal that is live (as in amp set to spk 1 and you measure there) you will get no reading from the unit as it is putting nothing to that terminal. If you can get a good pic of your meter setup the way you think it should be I can more than likely verify that it is correct! |
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Gold Member Username: KeggerWarren, MICHIGAN Post Number: 2576 Registered: Dec-03 | Actually here is a pic of your meter and I have marked where your meter probes should go. DO NOT! put the probes in the other side as that is for amps and would be a dead short. Also it looks as your meter does not allow you to select the range but does give you a millivolt setting that is marked in yellow and from the description of your meter it should be able to read low enough with no problem.  |
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Bronze Member Username: LovegasolineNYC Post Number: 14 Registered: Jul-05 | Kegger, My error. Milliamps was a typo. I tested with the meter set to millivolts (no additional range selction is needed on the meter) and the probes connected correctly (yup, that's my meter & it was setup as your arrows indicate). Again, all input devices were removed, the input switch was set to Tape #1, speakers removed, 'Speakers A' switch set to the On position, 'Speakers B' set to the Off position. I re-tested. Initially, ths is the reading I got: Speaker A Left Terminal: 9.1mv Right Terminal: 2.2 mv I kept removing and replacing the probes and retesting, and the reading would fluctuate slightly each time, but in the end it seemed to settle around the 2mv +/- reading Left: 2.3mv Right: 2.1mv For 'Speaker B' left & right terminals, a similiar 2mv -2.5mv reading. ??? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 4954 Registered: May-04 | Re; Speaker stands I just always start out with some concrete pavers and some "cinder" blocks and a few various pieces of wood and MDF to allow me to work out what I think I want for the speakers and room I'm working with. The concrete is, at this point, experimental and offers a good support that won't add anything to the sound. Placement in the room is more important than the stand at this point. After I've determined what size stands I'm going to work with and where the speakers will sit in the room, then I proceed with a final stand. I'm not much for voodoo in specially dried woods or magic materials of any sort. But the difference between placing your speakers on a chunk of concrete paver, a double layer of 3/4" MDF and a piece of solid oak are noticeable. Not dramatic as the magazines and advertising will suggest, but notoiceable none the less. The pavers, plywood and so on are just a way to get you started so you can determine whether this or that size and type of stand might work best for your speakers. I find a difference between whether the cone goes under the speaker or under the piece of material the speaker sits on to change the character of the music. There are some DIY support ideas on the forum (https://www.ecoustics.com/electronics/forum/accessories/55.html) and you can find more DIY on the web. Experiment and decide what works best for you. A good source of engineered maple is a kitchen cutting board which can be found in various thickness and sizes. |
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Gold Member Username: KeggerWarren, MICHIGAN Post Number: 2587 Registered: Dec-03 | Yes good results, I'm glad. Generally the reading is a little high when the unit is first switched on then it will settle down, sorry for not mentioning that. Your amp is probably in darn good electrical shape then. Congrats! |
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Bronze Member Username: LovegasolineNYC Post Number: 17 Registered: Jul-05 | Kegger, Yeah, the high reading/low reading was a little disconcerting at first. I'll do the bias testing if I ever manage to get my hands on a manual. Next stop.....speaker upgrade. Thanx a bunch for the generous help! Neal |
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Bronze Member Username: LovegasolineNYC Post Number: 19 Registered: Jul-05 | Jan, Thanks for the link. I'm filling my head with new info daily & the funrinture/placement tips will come in handy. I also need to up my critical listening to provide a matrix for theoretical knowledge, lest it become too abstract. Thanx for all the amp instruction. I think the next step in this system is upgrading my speakers. |
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Silver Member Username: CheapskatePost Number: 217 Registered: Mar-04 | radio shack employee clueless. LOL thanks for that one JVigne! i remember having a knock down drag out argument with a clueless employee who claimed that it's IMPOSSIBLE to use headphones as emergency low quality microphones. even after acknoledging the common voice coil/magnet structures of both he still thought he knew what he was talking about. i wish i had remembered walkie talkies and doorbell/PAs as both use SPEAKERS as microphones. the last time i was in the shack... some comission starved employee tried to get me to buy $30 monster cables for the $20 soundcard that i bought when i only needed RCA-1/8" male stereo adapters. cables do make a difference, no doubt, but it's silly to spend more on them than the gear itself... talk abou relentless! LOL radio shack is only a last resort. |
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