ok, I'have added some futures on my control room amp with Steve st/mono idea:
1) A balanced receivers in front of the network 2) switching input beetwen Stereo Buss/2 trk return 3) bufferded volume control for headphone Amp. 4) an active bias current distributor, here I need to know if R1 can be adeguate.
4) I have added a load resistors at the +/- rails of the out put amp, ( R59/R60/R62/R61 ) with this value seams to me the out impedace is 2K
the quastion here is : what the better output impedence for drive a pair of amplified monitor boxes
there are mistake for sure, that I cant recognize. so pleas let me know were I go wrong.