Soundtracs CM4400 channel strip "Rack" and cut PCB in half.

[Johnblue]

Hello All! i think this is my first real post here, I need some help. I'm working to "rack" 8 channels of my Soundtracs Cm4400, and i've gotten pretty far. I cut the PCB in half and rerouted everything into a working circuit, but im having trouble with the output, it sounds pretty good now, but its distorting when the "new" output fader pot is 3/4 of the way up. basically, its too hot... and i want some input... on the output... the last gain stage that is after the "RETURN" input.

the pinout goes to a TT patchbay module thing that i also salvaged and am using.  the EQ in/out switch goes to SEND, and thats normalled to "RETURN" then that goes to the last stage which is really the only thing i have to figure out...

its all TL074, then a 5534 output which was after the original fader, feeding the direct out and what was the pan pot.

i realized that the output stage now looks almost identical to the line input amplifier, minus the trim pot and switching a coupling resistor for a cap. 

all of the el caps regarding the circuit are 22uf 25v...

right now i'd like to know your suggestions on where to add the fader, i put a pot where the fader was, and its working, but im not sure i coupled it correctly,  now its coming off C38, and feeding the input of the second stage... would you do this? or should i copy the line amp and add what is a trim pot there?  if you were to add the fader, would you do it where i did? how would you best couple it?

whats the best idea on an output capacitor to resister for an unbalanced line output? now its 22uf feeding a 47ohm resist0r...

what would you guys do?

 

[abbey road d enfer]

As you surmised, the way you connected the VR is wrong; there is no attenuation, only gain.
Ther are two possibilities. See attachment.

 

[Johnblue]

oh! thank you! I see what is going on.  thanks!

what is the theory for best cap and resistor output combo for driving line level off of the 5534? i think ive read that larger caps 1000uf etc are best is that true? is bigger better?

 

[abbey road d enfer]

is bigger better?

Yes, up to a point; the usual law of diminishing returns apply. It depends on the expected load. 5534 is designed for driving loads down to 600 ohms. Using 1000uF gives a -3dB LF point at 0.26Hz. At 20 Hz, the signal is down only 0.0008dB.
Using 220uF, for a -3dB point at about 1.2Hz, and -0.016dB ar 20Hz, is perfectly acceptable.
Even this lower value may look like overkill, but in order to reduce distortion, it is important to keep the voltage across coupling capacitors as low as possible.
Please note that increasing the value also increases the size, which increases sensitivity to induced interference and possible x-talk; that may or may not be a problem.