I replaced the 5532/5534 with OP604/2604. I am also testing some output transformers, starting with old Altecs here.
Since you're out to do opamp swaps, the I/O section is the nice first touch, but there's more you might want to experiment with.
Try OPA404 as the quad opamp. Remember there's one on the turbo board as well. While a modern opamp in the I/O section will clean up t hings a lot, OPA404 actually changes compression characteristics. The TL074 is "too slow and distorted" for the sharp rectified audio discontinuations. While it results in the familiar SSL punch sound, it's obviously distorting in many ways, most obvious on fast attacks and stereo imaging. OPA404 takes the compression more into the mastering area.
I went further and tested OPA604 as the VCA driver's as well. Surprising compression characteristic change, again obvious on fast attacks and imaging. Some would say it makes no difference just how crappy opamp drives the control signal, but don't take this from me, and hear it yourself. It's not subtle.
August 18, 2004, 09:42:38 AM