I recently purchased a TEAC 3340 quad reel to reel deck. It is connected to my Marantz model 150 tuner and model 4140 quad amp. As with almost all quad stereo systems, The 4140 can take any stereo source and synthesize it into quad. I also have the SQ decoder. I was interested in taking a two channel source and using the 4140 matrix system, then recording that in quad on the tape deck. However, there is no signal to the tape deck for the rear channels using the matrix or the SQ decoder output. I am guessing that the quad decoding is done after the pre-amp output. Is there anyway to record The matrix or SQ output of the amp? The amp does have pre-out main-in jacks, but I don’t think using those would make any difference.