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Old 23rd April 2007, 07:40 PM   #1
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Default DC offset on Denon PMA 2000

Hi this is my first post,
I just purchase a used Denon PMA 2000IVR interated amp, age is about 4 or 5 years old. I tested the DC offset and the L was 2.1 and right 12.8 after a 2 hour warmup. The right seems alittle high for a 4 yr. old amp.
My concerns are:
1. Is this normal for a 4 year old amp? My 20yr. old Yamaha is well under 7 both sides.
2. I have read that below 10mv is where you will get the published distortion specs for the amp, in this case .01 at 80watts. At 12.8 how much more distortion am I getting?
3.Is the right channel going to degrade further, or will it stabilize.
4. Is there anyway to adjust the offset on the PCB, as in older gear.
5. Does anyone have the service manual?

I have limited electronics knowledge compared to most users on this site, any help or knowledge is greatly appreciated.

Thanks,
lukesolo
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Old 23rd April 2007, 09:55 PM   #2
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Hi welcome to DIYaudio.
1. Hard to say-amp my have been a little high when new-guess you know now the better of the two.
2.12.8mv is a little high and needs to be adjusted back into spec.not only causes distortion but could trip the protect circuit.(distortion destroys tweeters).
3.Yes it will probably degrade more in time if not addressed.
4.Need a service manual to answer this question.
5.Sorry, I do not have a service manual.

Again Welcome to DIYaudio


Dave
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Old 24th April 2007, 07:28 AM   #3
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Default service manual

Thanks eaglekeeper,

I am the second owner so I'm not sure if it was high when new. I would think that most new amps would be much lower. I did find one site called pacparts that says they can get the manual for $25 + 10 shipping. The shipping seems ridiculous. Still looking for cheaper.

Thanks for the advice.

Lukesolo

P.S. nice pic of the 15
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Old 24th April 2007, 09:52 AM   #4
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lukesolo
Someone here may have the manual.Be patient.

Dave


Pic Is a F-15E "Strike Eagle"from Seymore Jonhson AFB .Work on these birds during "Desert Storm and Operation South watch"...
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Old 24th April 2007, 11:49 AM   #5
Eimac is offline Eimac  United States
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Lukesolo,

You might be able to find a service manual here

http://www.servicemanuals.net/

The cost is about $15.99 US and you can download them in a PDF format or have them shipped in a paper format.

I found a service manual for an old Sherwood amp S6040CP from the 80's so you shouldn't have any problem finding one for your Denon.

There should be a pot on the circuit board, one for each channel, for adjusting the offset voltage. Had to do the same thing with my old Sherwood amp. If you can find a service manual the instructions on how and which pot to turn will be in the manual.

Good luck.
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Old 24th April 2007, 05:54 PM   #6
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Thanks, unfortunately they don't have it. The search continues........
I did find another older thread on this amp and one of the members on this thread said he has the manual to the slightly older version. I tried contacting him but because I'm a new member I'm still being moderated. If any member out there has this amp maybe you could measure and see what numbers you get.

Thanks
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Old 1st May 2007, 05:07 PM   #7
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Ordered one from pacparts.
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Old 1st May 2007, 11:07 PM   #8
mikeks is offline mikeks  United Kingdom
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http://fileshare.eshop.bg/downloadsm...A-2000IVR.html
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Old 2nd May 2007, 01:14 AM   #9
Leolabs is offline Leolabs  Malaysia
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Do the offset reading so important regarding it's an old amp???
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Old 2nd May 2007, 06:20 PM   #10
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Thanks mikeks for the link to the service manual. If you adjust the idling current(bias) does that affect the dc offset?
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