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Denon POA 6600 Thread

There are 2 caps that I replaced on the PSU board, C003, 004, 470µF/100v. The old caps measured about 460µF.
They were replaced with United ChemiCon KYA 470µF/100, the new ones actually measured high at 513µF.
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Cheers,
James
 
On the speaker output board there are 4 carbon film resistors.

R701, 10ohm shown on schematic, 4.7 ohm actually installed.
R702, 703, 4.7 ohm.
I found some Vishay 4.7ohm 1w PR series metal film in my collection and used them in these positions.
R705, 56k ohm. Used a SFR25 part here.

I haven't fully decided about the speaker relays, but I ordered a bunch of Omron G5RL-1A-E-TV8 DC24 parts.
https://www.mouser.de/ProductDetail/Omron-Electronics/G5RL-1A-E-TV8-DC24?qs=TF2qWOo/Jh2DpOurHofHkA==
At 16A contact current I would think that they should be OK to replace the original 5A parts, so I will probably change them tomorrow. Footprint wise they are a drop-in fit.

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Cheers,
James
 
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Soundscape said:
Enter...the amp chiclets
:biggrin:
Since ya have more than one of those amps, have ya compared one with bypass caps & one without?
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I have yet to have 2 working amps to try out.
It's one of those things that probably can't make a hearable difference all by itself, but at the same time can't hurt.
Part of the theory of making as many small incremental improvements that hopefully eventually add up to something useful.

But on the other hand, I am a firm believer that anything that can be done to clean up the power supply pays off through the entire device.

:beerchug:,
James
 
Soundscape said:
I have a theory the inner plate forming tosses around the C value on old & new caps. In other words I rarely test them, lol.
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I do usually test all old parts. you can get a bit of an idea of of how many hours it had. The A-1020 for instance. A lot of caps in it were cooked to have their rated value. Both of these Denons look very pristine inside and out, the caps all test at or near nominal and the solder connections look nice. I get the feeling that they are low hour units.

I like to read the date codes too, it gives a "no later than" date. With my 5 Marantz amps for instance it gave me a way to compare the approx production date and compare that with the engineering changes that they made through the series.

:beerchug:,
James
 
Bratwurst7s said:
But on the other hand, I am a firm believer that anything that can be done to clean up the power supply pays off through the entire device.
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I'm right there with ya on power supply health brotha.
Bratwurst7s said:
It's one of those things that probably can't make a hearable difference all by itself, but at the same time can't hurt.
Click to expand...
I've had a good experience with power supply bypass caps in tuners. Haven't tried it in amps yet.
 
Soundscape said:
I'm right there with ya on power supply health brotha.

I've had a good experience with power supply bypass caps in tuners. Haven't tried it in amps yet.
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First time for me in an amp. I did a lot of stuff with CD players in that regard. Bypass caps on the filters, ultra fast soft recovery diodes, heat sinks on voltage regulators and stuff.

:beerchug:,
James
 
I'm still undecided about the speaker relays. The protection relay was a no brainer because I figure it is a 2 hour job to replace, minimum.
But the speaker relays are real easy to get at, I figure a half hour open to close. And if it really is a low hour unit I am thinking of leaving them in place for now. I go back and forth every 15 minutes.
 
Bratwurst7s said:
First time for me in an amp. I did a lot of stuff with CD players in that regard. Bypass caps on the filters, ultra fast soft recovery diodes, heat sinks on voltage regulators and stuff.

:beerchug:,
James
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I lied a little. Didn't wanna shat on your efforts. I tried bypass caps once in the secondary mains in a Yammie M-60. Pulled em right back out after setting it up in the living room.
 
I went through bypass thing in the signal path and speaker crossovers. Long gone and all removed. Don't like the sound. Better one very good cap.
But on the main filter caps in the PSU the theory makes sense. The only place where I will do that.

It was interesting to study the schematics of several CD players and check the differences in the "Japanese market only" version. They will have bypass caps on those main filters and often the where the bridge rectifier is made up of individual diodes they are all doubled up.
 
Soundscape said:
I lied a little. Didn't wanna shat on your efforts. I tried bypass caps once in the secondary mains in a Yammie M-60. Pulled em right back out after setting it up in the living room.
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You and all of my other AK Pals are officially allowed to shat on my efforts.
In the immortal words of Robert Heinlein "This is Liberty Hall. You can spit on the mat and call the cat a bastard".

:beerchug:,
James
 
Bratwurst7s said:
You and all of my other AK Pals are officially allowed to shat on my efforts.
In the immortal words of Robert Heinlein "This is Liberty Hall. You can spit on the mat and call the cat a bastard".

:beerchug:,
James
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Lol...well said sir. I might have had a better experience placing the bypass caps across the main filter caps vice the secondaries. Sounded great on the bench. Put it all together and then it sounded foul in the living room. I'm kinda modification shy ever since.
 
Bratwurst7s said:
Yep, Wima, eat your heart out. :biggrin::banana:

Not all ECW are the same. Some have tinned steel leads and some have tinned copper leads. Fellow AK Pal zaibatsu and I looked into that a couple of years ago and so far have identified 8 or 9 that have copper leads, going from 4.7µF on down to 0.01µF
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Wish the Z man would chime in more. Hint hint. Always thought he was cool on past threads.
 
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