I have an older 2006ish model pioneer Elite receiver (among other similar models) that I am attempting to modify.
You see some higher end models have a "pre-amp in / out" where you can bi-pass the internal audio processing (bass, treble, loudness, delay, echo, etc) instead it passes the signal directly to the amp chips themselves. And I have some much cleaner sounding pre-amps that work much better than the internal pre-amp in most recivers. So I'd like to solder in some wires from an RCA input on the back directly into the amplifier section, because this series of recivers has a nice compartmented set of boards. So there is a power board then a DSP processing board a volume/input managing board, a pre-amp board and of course the amplifier section.
Most of it is easy to figure out what each ribbon cable between them is carrying (signal/voltage wise) as most of it is printed right on the PCB plus I also have the schematics.

The pre-amp board in this unit even shows the various channels printed as "FL / FR / SR / SL / C" (as in Front Left Surround Right etc...) however in each of these sections on the PCB output connector there are 5 pins/traces per channel labelled as "GATE+ / GATE- / BIAS+ / BIAS- / NFB" I am not sure which one carries the pre-amplified audio signal? I mean there are no other wires going into the amplifier section (other than from the power board). So the audio must be carried along 2 of these 5 pins!
I assume "GATE" is for turning the amp channel or or off - thus I assume that "BIAS" would be the "gain/volume bias audio"?

But I am not sure, thus I am here asking if anyone might have so input as to how a typical Pioneer reciver lables things.
I have provided a portion of the schematic here with some RED/BLUE dots where I assume the pre-amplified audio signal is?

 

I might add that this is inside a "Direct Energy" amplifier receiver. Which from what I can tell simply means they provide power directly to the amp IC's via the heatsink itself.
However I suppose in theory it might mean that there is no actual "audio channel" pushed into the amp but rather fluctuations in power/voltage that mimic the audio signal? (Kind of like how an old LPT printer port could produce audio from varying digital signals in patterns that re-produce sound)

Some background here as I've spoken with others in the past and all of them seem to get "annoyed" with me as if I have no clue about electronics and they move on.
So I figure perhaps if I start with what I know and how I understand/learn it might help whoever is reading this.
While I am quite famlilair with most electronics, I'm not familiar with actual circuitry theory itself. I am ecellent at repairs and modifications / soldering etc... I also understand, resistors, capacitors, diodes, transistors, logic etc... but when it comes down to design and theory I lack the understanding that "connects" it all in my head... I mean I feel I am on the cusp of understanding it all (like it almost all makes sense) but every where I look to fill in the missing "blank" I can't find what I am looking for.
And most electronics teachers teach "by the book" and "by memorizing these math concepts" but my mind I does not work that way - I cannot just memorize random facts/math without some "concept" to apply these ideas/theories to.

For example:
If you provided me a bunch of random toaster parts to build a toaster (and did not tell me the point was to build a toaster) I would have no idea what the intended purpose was. Reason being in my mind I could see this collection of various parts (like element, lever, resistor, cord etc) as having multiple possible purposes. I might see a "wet sock drying" tool that could be built, or an ice melter or, a small room heater, or even a toaster etc etc... with each of these "concepts" each part is used in differing ways to achieve the intended outcome. So to me without knowing what the intended "goal" or "outcome" is applied to then I have no idea how to use/apply these individual parts. Same way I have no idea when a teacher is telling me "V=R/I" or whatever means without having an actual "concept" in mind to apply this theory/idea to!
(It seems like I cannot memorize random facts in my mind if the facts have no value -so telling me random math equations & math concept that are solving nothing & applied to nothing - means nothing - thus it is forgotten - as there is no "importance" associated with said equations - and thus my mind does not "save" said info). If I needed to build a toaster then I would have a reason to learn the concepts of how all the parts work together to produce an outcome - and I learn. But current schooling/teaching never gives you the "point" to learning what they are teaching.

However as example of schooling that worked to help me learn, was of my own, we got to build projects from premade kits making our own PCB's in a dip tank etc. I build an audio VU meter and noticed there was capacitors near the input audio signal bridged across +/- ... I wondered what would happen if I changed their values what would it affect what would the outcome be? and so I did just that. And when I did I saw the result! It altered the peak speed, and fall off rate of the VU meters. Thus I saw the affect various capacitence values had - and I understood the concept of capacitence. No traditional teaching does this.
And so I am trying to learn as I do which is... with each time I repair items I pick something new up as I see outcomes.

(So please keep this in mind if you are considering replying).

 

I have an older 2006ish model pioneer Elite receiver (among other similar models) that I am attempting to modify.
You see some higher end models have a "pre-amp in / out" where you can bi-pass the internal audio processing (bass, treble, loudness, delay, echo, etc) instead it passes the signal directly to the amp chips themselves. And I have some much cleaner sounding pre-amps that work much better than the internal pre-amp in most recivers. So I'd like to solder in some wires from an RCA input on the back directly into the amplifier section, because this series of recivers has a nice compartmented set of boards. So there is a power board then a DSP processing board a volume/input managing board, a pre-amp board and of course the amplifier section.
Most of it is easy to figure out what each ribbon cable between them is carrying (signal/voltage wise) as most of it is printed right on the PCB plus I also have the schematics.

The pre-amp board in this unit even shows the various channels printed as "FL / FR / SR / SL / C" (as in Front Left Surround Right etc...) however in each of these sections on the PCB output connector there are 5 pins/traces per channel labelled as "GATE+ / GATE- / BIAS+ / BIAS- / NFB" I am not sure which one carries the pre-amplified audio signal? I mean there are no other wires going into the amplifier section (other than from the power board). So the audio must be carried along 2 of these 5 pins!
I assume "GATE" is for turning the amp channel or or off - thus I assume that "BIAS" would be the "gain/volume bias audio"?

But I am not sure, thus I am here asking if anyone might have so input as to how a typical Pioneer reciver lables things.
I have provided a portion of the schematic here with some RED/BLUE dots where I assume the pre-amplified audio signal is?

This stage is the Voltage amplifier( V drive ) for the final power amp stage. The connections provide the biasing voltage, Negative feed back and the complementary drive signals. The two stages work together, to isolate and use another V drive is almost impossible unless you know what you are doing and knows how to design voltage amp to drive current amp output stage.
I will say to forget and try to fix it, if you have issues. The sound quality is no limited to V amp, but through out the design you get good sounding amps

 

So how does the actual audio signal/sound get to the amp? I mean this type of amplifier still requires an analog audio signal to amplify correct?

 

Can say without looking at the whole diagram

 

Can say without looking at the whole diagram

Service manual:
I wonder then maybe the audio signal/line is on the input of the V-Amp assembly - as the photo I linked was on the output.

 

Service manual:
I wonder then maybe the audio signal/line is on the input of the V-Amp assembly - as the photo I linked was on the output.

Might also add that I have more than one of these receivers and this one was damaged in shipping. The front/face no longer works with the remote control. There for I wanted to by-pass the internal volume/per-amplification/bass/treble etc... and just directly connect my own pre-amp to the amp inside, as the amp section of this receiver still works fine. And my external pre-amp as remote volume control.

 

I've had a much closer look at the manual (keep in mind it's over 60 pages of actual hardware detail to skim through). Anyways I finally noticed the actual "pre-amp" section is labelled. So I think now I know where the "pre-amplified audio" goes into the amplifier now.

I have attached an image:
I think this is my answer/solution.... I can just cut or omit the actual pre-amplified signal from reaching the V-Amp board and insert my own Pre-amp leads.
I did not think to read the other side of the V-AMP - the input ribbon cable as I assumed this board was the pre-amp and thus I wanted to by-pass it. (The v-amp in ribbon cable actually labels the FL+ GND / FR+ GND etc) So this must be where I inject my pre-amp signal in. Question is the ground is labled "AG" I assume this means AUDIO ground rather than power supply ground?
Do you suppose these other pins listed on CN105 such as the +15v needs to be coupled/matched with the FR / FL signal? Or would they just need to be passed off to the V-amp board with my injected audio signal?

Your answer did help me realize that I was not looking at the pre-amp (it just looked like a simple transor amp like the photo I attached - the parts are so similar to the V-Amp parts) ,
Which caused me to have a closwer look at the service manual, where I and actually found the missing "pre-amp" portion of the reciver, reason I never found it before is A: there is over 60 pages to broswe through and B: it is not listed under "Pre-amp" it's listed under "Main Controll Assembly" - which I had assumed was to control the inputs / switching etc... (which it is - but this section also contains the pre-amp)
Anyways I appreciate you actually replying to me with an actual responce as I've found most people I try to discuss electronics with on forums are quit standoffish towards me, or reply once then never again.

 

Nice piece of hardware
Pioneer have good sound actually.

So what is it tht you actually want to achieve ?

The problem with the amp is that it has a DSP. Integrating into that is no easy and feasible. Actually you can use the power amp by tapping into the volume ( page 11 ) can work.
This thing has MOSFET output stages ( not a fan ) but could sound beautiful. The DSP part could be the one degrading Hi-Fi but now these days, DSP's are actually good.

You might be able to repiare the broken one I believe.

 

By the way the volume is a long shot. Since it a Digital one.
You inserting a preamp could overdrive the stages into clipping.

 

Nice piece of hardware
Pioneer have good sound actually.

So what is it tht you actually want to achieve ?

The problem with the amp is that it has a DSP. Integrating into that is no easy and feasible. Actually you can use the power amp by tapping into the volume ( page 11 ) can work.
This thing has MOSFET output stages ( not a fan ) but could sound beautiful. The DSP part could be the one degrading Hi-Fi but now these days, DSP's are actually good.

You might be able to repiare the broken one I believe.

What I want to achieve? Well the receiver does not respond to the remote control anymore. I assume the IR codes are stored in one of the actual "Pioneer IC's" which would be almost impossible to find online to order / replace. So I cannot control the receiver remotely - I have to get up to change volume.
Also I've owned many Pioneer receivers like this one that have an actual "jumper RCA jack" that is "Pre-amp in/out" and if you pull this jumper out - you can plug your own "HiFi headphone amp" into here and the sound quality is improved significantly. This is because so many receivers now are designed for 5.1 and more speakers. There for there is all kinds of processing done to the audio (even when you select 2 Channel mode) the added "bass / treble" etc is just not well done compared to using a "digital EQ" on a PC to adjust the audio to the amp.

For music listening I only use high end Pioneer receivers with these "Pre-amp in/out jacks" as the sound quality surpasses even the classic ADCOM 555 ii I had. (Typically they are 130w / 150w or 160w per channel too)

I know this receiver I am working on now has a nice 120w per channel amp - so I don't want to let it go to waste just because the remote control no longer operates it.
(I know I could just set the volume to 0db and then connect it to my headphone amp and set the volume to 1 and then turn the amp on and control the volume from Windows) but as I said the built in pre-amp and bass/treble processing is not as clean as doing that directly at the source.
I have multiple recivers here and only a very few of them (typically from the 90's) have decent bass/treble. Anything newer just pales in comparrison now. But the amps inside these better sounding processing recivers are not as good as the more modern ones.