Mod tips wanted:Denon Power Amp

clm811 · 28th September 2008, 08:51 AM

I recently acquired a second Denon POA2400 which needs replacement of a few parts. This is their "Optical Class-A" amp, rated 200W/8ohms, 350W/4ohms. My working unit is great, but I see that many parts are less than "audiophile-grade"...

I figure as long as I'm in there, maybe I could upgrade some critical parts in the signal path and power supply rails.

Anyone modded these amps, or have suggestions for changing those parts which would give the "most bang for the buck"?

-chas

First image is the voltage amplifier stage 1

clm811 · 28th September 2008, 08:53 AM

...Or perhaps I should take the terrific (potted toroid)power transformer and build a new amp from scratch(any design recommended for +/-72v rails)?

Any guidance or opinions are welcome.

Thanks,

-chas

Next image is the current amp stage 2

clm811 · 28th September 2008, 09:00 AM

Finally, the main(current) power supply.

The bridge rectifiers & large caps could be replaced(remember-bang for the buck)... any suggestions?

-chas

clm811 · 28th September 2008, 09:07 AM

Lastly a photo of the amp itself, sans cover(showing power supply, boards and heatsinks).
-chas

jacco vermeulen · 28th September 2008, 11:40 AM

Quote:

Originally posted by clm811
take the terrific power transformer and build a new amp

Leach amp boards : http://www.diyaudio.com/forums/attac...amp=1222149740

Such a power amp is one heck of a conversion amp, as are all late 80s Denon numbers, only requires a board transplant.

clm811 · 28th September 2008, 07:39 PM

Thanks, Jacco! Looks great, BUT- Where can one obtain plans or purchase the boards/kit, etc.??

And I still welcome any mods/tips for this impressive amp.

Regards,
-chas

clm811 · 29th September 2008, 04:08 PM

On the Leach Amp WiKi.

Now if we can just get enough requests...

clm811 · 1st October 2008, 05:22 AM

The amp diagrams above show no caps in signal path, BUT there are resistors and bypass caps (as well as power supply caps and bridges(obvious candidates).

Which of these do you folks think are most inportant to upgrade in quality? Or should ALL parts be upgraded(too expensive and I'd probably go to another circuit).

TIA -chas

clm811 · 24th October 2008, 10:55 PM

I've decided to repair/restore the POA2400 and sell it off to fund premium parts for my Rasmussen-Leach/clone amps...

Anyone want to buy a nice Denon POA2400?

-chas

nigelwright7557 · 25th October 2008, 09:37 PM

I would just replace the electrolytic capacitors.

28th September 2008, 07:39 PM	#6
clm811 diyAudio Member Join Date: May 2002 Location: Northern California	Where to find? Thanks, Jacco! Looks great, BUT- Where can one obtain plans or purchase the boards/kit, etc.?? And I still welcome any mods/tips for this impressive amp. Regards, -chas

29th September 2008, 04:08 PM	#7
clm811 diyAudio Member Join Date: May 2002 Location: Northern California	Found it, Thanks! On the Leach Amp WiKi. Now if we can just get enough requests...

1st October 2008, 05:22 AM	#8
clm811 diyAudio Member Join Date: May 2002 Location: Northern California	Parts upgrade suggestions? The amp diagrams above show no caps in signal path, BUT there are resistors and bypass caps (as well as power supply caps and bridges(obvious candidates). Which of these do you folks think are most inportant to upgrade in quality? Or should ALL parts be upgraded(too expensive and I'd probably go to another circuit). TIA -chas

24th October 2008, 10:55 PM	#9
clm811 diyAudio Member Join Date: May 2002 Location: Northern California	Decided to go another way I've decided to repair/restore the POA2400 and sell it off to fund premium parts for my Rasmussen-Leach/clone amps... Anyone want to buy a nice Denon POA2400? -chas

25th October 2008, 09:37 PM	#10
nigelwright7557 diyAudio Member Join Date: Apr 2008 Location: Carlisle, England	I would just replace the electrolytic capacitors. __________________ http://www.murtonpikesystems.co.uk PCBCAD50 pcb design software.


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