Quote Originally Posted by Alien_Shore View Post

..........I'm wondering about those old inductors they used...I am definitely going to test some variations around using original coils, new caps/ new inductors, new caps/ etc............

It is really nice to see that so quickly you have started to suspect ( rather appreciate ) these old inductors. I will tell you (and everybody else) not to lose these,and to preserve them, as these inductors were part of a 30/40 yr old design frequency-shaping circuit. It wil be very difficult to duplicate them today. Inductors used in the mains ckts are not important, as they can be easily duplicated, but not these.

I remember reading a small story in the late 80's/early 90's issues of the "studio sound" magazine. It was about the famous API-550A equalizers, which used a simple two stage transistor amplifier with the output being loaded with a trafo, from which the feedbacks were taken for the frequency shaping purposes, via a muti-way switch. As API was closing/closed due to financial troubles, somebody (he was a big tech head of that time) wanted to replace the existing 550A circuitary with more modern high end components, (as the 550A innards were very clumsy and dirty looking) and continue selling them. But they never succeeded, even after trying it for two yrs., and the original output trafo could not be duplicated. They just could not duplicate the sonic quality of the original 550 equalizer.