While I did search quite a lot, it seems that I never find topics/threads about using just the pre/pro or power amplifier of an integrated amplifier/receiver.
Well... while the AVR-2808 does have Pre-out, I would like to disable the power amplifiers as it seems they still use power.
Sorry that I didn't have a look myself yet, but I'm not that good with electronics...
I know the usual stuff, but I'm pretty sure there's some protection circuit that will screw things up.
I don't want to turn it into an $18k SIM Audio pre/pro (I would if I could for just a couple hundred $), but I just want less heat coming from the 2808 and using less power.
Any help/suggestions are much appreciated!
Well... while the AVR-2808 does have Pre-out, I would like to disable the power amplifiers as it seems they still use power.
Sorry that I didn't have a look myself yet, but I'm not that good with electronics...
I know the usual stuff, but I'm pretty sure there's some protection circuit that will screw things up.
I don't want to turn it into an $18k SIM Audio pre/pro (I would if I could for just a couple hundred $), but I just want less heat coming from the 2808 and using less power.
Any help/suggestions are much appreciated!
Then just pay the power bill.
There is an AWFUL LOT of "stuff" in there. 167 page service manual! And it is all tightly packed and inter-connected so many ways.
At glance, the power transformer has fat red wires to a plug on the power amp board. Un-latch and un-plug. The power amp is now dead.
However there are many side-paths. While most of the box gets power from another PT winding, I have a strong suspicion that the main brain monitors almost everything, would call a dead power amp a "fault", and throw a fit. I also see several plugs that, stunningly, would cause a BLOW-UP if unplugged in error.
Let it be.
I have just taken a slightly smaller model of Denon AVR apart (amplifier fault) and the lack of (immediate) structure is stunning. There are boards everywhere which are interconnected in strange ways. The main transformer has got a plurality of auxiliary windings generating auxiliary voltages for unknown purposes. The parts count is enormous and explains why the full performance reliability is likely to be somewhat limited. Most repair requires a specialist and much is not worth paying a repair bill for due to the man-hours required.
It is an impressive construction with many good parts and actually not expensive for the lot you get. I found a "main-brain". But, it is a unit you pray for will work and also I will recommend you to TOUCH NOTHING if it works.
It is an impressive construction with many good parts and actually not expensive for the lot you get. I found a "main-brain". But, it is a unit you pray for will work and also I will recommend you to TOUCH NOTHING if it works.
Thanks for the replies.
I was hoping for someone that read about the Simaudio/Denon 2808 article and knew an easy way because they wanted to try something similar, as I can't be the only idiot wanting to try something like this (But I may have a different reason).
I guess I will try to see what Samsara's suggestion will do, until I saved up enough money to buy a new Amplifier/Receiver or Pre-Pro.
Maybe I should've worded it a bit better, I need to study the schematics while others may see things real quick because they have a lot more experience.
I was hoping for someone that read about the Simaudio/Denon 2808 article and knew an easy way because they wanted to try something similar, as I can't be the only idiot wanting to try something like this (But I may have a different reason).
I guess I will try to see what Samsara's suggestion will do, until I saved up enough money to buy a new Amplifier/Receiver or Pre-Pro.
Dear community, KILLorBE, Samsara, FauxFrench,
again an excellent topic on diyaudio. Merci for sharing your knowledge.
I have a somewhat complicated set up with one denon AVR Amp as a Preamp (3808A), actually as an HDMI & audio source selector, with pre-out stereo output connectd to two mini-DSP active filters, with a second denon-AVR as a multi channel power amp with multi channel volume control (AVR-4306).
In short, I want to use my Denon AVR3808 as a line level preamp (because it is cheap and good). And I do not like that it gets hot, neither to waste electricity.
So I'm back to exactly the same question of KILLorBE: how to disable the power amplifiers; or how to drastically reduce the current drain.
I like the solution of Samsara to "decrease idle current at minimum". Not clear exactly what "minimum" means here, I may try to measure it somehow. I understand that the consequence will be strong distortion on output power amp cause class B behavior, which is OK as I'm not using the power output.
Now this leads me to my question:
As I still want to be able to use the headphone output; can I also safely remove current drain on the Front Left & Front Right ouput ?
In other words, does anybody know whether the headphone output of the AVR-3808 would be degraded by removing currend drain on the power amp ?
I have not understodd the service manual (which as usual is available in Page not found - HiFi Engine thank you hifiengine).
Thank you in advance,
Bonjour à la communauté francophone,
Daniel.
again an excellent topic on diyaudio. Merci for sharing your knowledge.
I have a somewhat complicated set up with one denon AVR Amp as a Preamp (3808A), actually as an HDMI & audio source selector, with pre-out stereo output connectd to two mini-DSP active filters, with a second denon-AVR as a multi channel power amp with multi channel volume control (AVR-4306).
In short, I want to use my Denon AVR3808 as a line level preamp (because it is cheap and good). And I do not like that it gets hot, neither to waste electricity.
So I'm back to exactly the same question of KILLorBE: how to disable the power amplifiers; or how to drastically reduce the current drain.
I like the solution of Samsara to "decrease idle current at minimum". Not clear exactly what "minimum" means here, I may try to measure it somehow. I understand that the consequence will be strong distortion on output power amp cause class B behavior, which is OK as I'm not using the power output.
Now this leads me to my question:
As I still want to be able to use the headphone output; can I also safely remove current drain on the Front Left & Front Right ouput ?
In other words, does anybody know whether the headphone output of the AVR-3808 would be degraded by removing currend drain on the power amp ?
I have not understodd the service manual (which as usual is available in Page not found - HiFi Engine thank you hifiengine).
Thank you in advance,
Bonjour à la communauté francophone,
Daniel.
I’m thinking PRR’s reply (#2) would be the most prudent - he’s speaking words of wisdom “Let it be”. 
With any of the most recent receivers - 5 yrs or so? there’s so much signal processing going on with the assignability of amp channels for surround effects, bi-amping, separate zones, etc, that I’d be very wary of messing with any internal connections.
Absent a connected load, would not the power amp stages draw little more than quiescent current - i.e. possibly less than that of, say a TV/cable box/PVR?
While I’ve experimented with using the front line outputs on my Onkyo surround receiver to drive an outboard power amp, I’ve never run it with the on-board amps for those channels also connected to another pair of speakers - perhaps there’s an automatic mute function to the internal amps for any channels connected?
With any of the most recent receivers - 5 yrs or so? there’s so much signal processing going on with the assignability of amp channels for surround effects, bi-amping, separate zones, etc, that I’d be very wary of messing with any internal connections. Absent a connected load, would not the power amp stages draw little more than quiescent current - i.e. possibly less than that of, say a TV/cable box/PVR?
While I’ve experimented with using the front line outputs on my Onkyo surround receiver to drive an outboard power amp, I’ve never run it with the on-board amps for those channels also connected to another pair of speakers - perhaps there’s an automatic mute function to the internal amps for any channels connected?
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