trouble with Denon POA 2800 amp - Anatech rsvp

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I have owned this amp new since 1998 and have enjoyed it's powerful
sound delivery, through my B&W P6, w/o fault until 10/2006.
Back in Oct/2006 my right channel failed.
I dropped same off to Denon Repair in Markham and, now after three
subsequent repair attempts, I am still confronted w/ no sound from Right Channel.
Following first repair - sound kicked in, until I shut system off and tried to restart
the following day - NO RIGHT CHANNEL
Same thing occurred following 2nd repair attempt, and finally on third repair
attempt - NO RIGHT CHANNEL at all.
Completed neophyte testing - alternating speaker wires, followed by
alternating output chords from pre-amp, to support fault is related to RC
of power amp.
Any ideas - I believe I read somewhere that a breach in solder connection
can show up once system heats up ( expansion occurs ) ?
Please help as my IPOD player is no match for my wonderful Denon/B&W system.

THANK YOU
 
Assuming they repaired the op stage.... I am tempted to think that the shop (unknowingly) used fake OP devices.... lots of fake sankens out there.

Another thing could be your relay is not kicking in, probably due to bad lytics.

Id you know what they repaired the first time, Anatech would have something to go on...
 
When you trun on the amp, do you heart a "click" after 2-3 seconds?

Is it running fine now? Is the issue intermittent?

Not sure what the problem is... please define the issue.... Looks like the repair shjop did'nt repair anything because there was nothing to be repaired, if so, whats the prolem?
 
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Hi stressbeater,
I know the guys at Denon. The best technician is Peter. He is Austrian.

It sounds like you have an intermittent fault there. If you want, I can have a look at it for you. I'm over in Georgetown, I don't know whether that is close to you or not. What your service history shows is that the fault may not have occured on the bench.

Please don't go wandering around with a soldering iron. You will erase any clues that may be there, making it harder to fix.

-Chris
 
K-Amps
1) no clicking sound after 2-3 seconds o/t standard delay associated with muting circuit
2) Amp is inoperative - no sound from right side ( channel )
3) Problem is not intermittent. When first noticed, back in Oct/06, their simply
was no sound from right channel. To ensure problem was power amp related I completed
neophyte testing by switching speaker cable to ensure same was not speaker or cable related. Also alternated output chords to ensure pre-amp was working properely.
Everything pointed to POA2800 right side ( channel ) problem.
4) Amp is back at Denon for the 4th time - fingers crossed.
 
ANATECH - THANK YOU for your response !
Amp is currently back at Denon for the 4th time,
If they are unable to correct problem, I would like to drop same off in Georgetown
for your personal assessment.
Please supply address and /or contact information for shop.

p.s. I would NEVER consider wandering with a soldering iron ( LOL )
 
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Hi stressbeater,
Okay, that's good. They might use a real tech on it now. At least a constant problem is traceable.

If you need to bring it to me (I hope not - I'd rather see Denon catch it to save you running around), PM me with the mail button. Just post if you can't and I'll send you mail.

Arif,
Yup! ;)

-Chris
 
Whatever happened with your amplifier? I really want to know as I have a Denon POA 2800 which is faulty too. It started with the left channel and now both channels are damaged. Sound is still coming out of both channels but it just doesn't sound right at all. Sounds like a lose connection and kinda "scratchy". Sound is also distorted and at low volume no matter how far I turn the vol. knob on the PRA 1500 (pre-amp). This unit was bought from new in 1994-1995 and this is the first time I'm experiencing errors with this amplifier.
 
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I have POA-2800 which I manage to fix it few years back and still is working fine.
I remember that I had to remove all solder and put a new one due the year and heat has dry all the solder and will not conduct properly.

If you can check the mosfet drivers 2SJ79/2SK216 - usually any loose contact or dry contact occur from heat and, this is result for scratchy sound too.

bekim
 
Seems to me that the POA 2800 isn't that perfect engineered after all. I've even heard it's "over-engineered"...

These two sentences are somewhat contradictory. The amp might be suffering from poor manufacturing quality, which is not necessarily related to engineering, or end of life failures (such as with capacitors drying out). Some semiconductor components even suffer a breakdown of the hermetic seal over time. Also, oxidation can also play havoc with plugs and switches.

All of the above can and does happen to any electronic equipment.

Is it worth repairing? Well, how satisfied were you with it while it was not faulty? Only you can answer this.
 
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Hi Shaun,
The amp might be suffering from poor manufacturing quality
The failures the Denon suffered have nothing to do with Denon as much as it has to do with the state of manufacturing. Wave soldering does not seem to work well. I don't think the component leads ever get hot enough to wet properly. Any hand soldering I've done are still great after 20 years, I have people bring things in for checkups every now and again.

Almost every brand suffers from the same issues, depending on component temperatures and similar things.

-Chris
 
I agree, Chris. I recently fixed a CDP that was in "as new" condition, though it is a few years old. Owner said he did not get much use out of it before it went faulty. A quick touch-up on some obviously stressed solder joints got it up and running in next to no time. Wave soldering produces pretty-looking joints but if the assembly is not sufficiently pre-heated before going through the solder "wave", this is the kind of result one gets.
 
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Hi stressbeater,
How did your amplifier turn out? It must be repaired by now.

I found out that Peter is no longer working there at Denon. He's an excellent technician. There are other good techs there also. Most factory service shops are not the best (sadly!), but the one at Denon is pretty darn good.

Hi Shaun,
CD players are another kettle of fish. Often the alignment isn't as good as it could be, that includes mechanical (even if there are no adjustments) alignments. In truth, the mechanical set up is critical. Once that is done properly, you can optimize the servos. The new auto-aligning servos do not fill me with confidence after watching the results on the bench.

The sound quality is dependent on the alignment in a CD player. Proper alignment reduces digital errors directly. This can be very audible.

-Chris
 
I'll try to contact a local audio/electronic repair shop. If it turns out to be too expensive, I might just jump on the Virtue Audio bandwagon.

Speaking of Virtue Audio and Class-D amplifiers in general...How do these amps compare to the traditional Class A, Class A/B types when it comes to durability, electrical and mechanical errors?

I don't think that Class-D amps needs to be serviced as often as the traditional types, am I wrong?
 
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Hi Geopoliticus,
What's too expensive?
Also, take it to an authorized Denon warranty shop or the distributor in your area. If your local shop does TV's and VCRs, avoid them like the plague! TV people don't do very good audio work, and they tend to be expensive as well.

How do these amps compare to the traditional Class A, Class A/B types when it comes to durability, electrical and mechanical errors?
I was under the impression that you would be interested in sound quality first off. I haven't heard a class "D" I like yet. Also, remember that when you are asking about construction quality, that depends on the company and what they are willing to pay for the build. Nothing else.

I don't think that Class-D amps needs to be serviced as often as the traditional types, am I wrong?
Yes, very. And they require better test equipment to repair properly also. I'll bet they are throw aways once they need service.

-Chris
 
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