I admire your persistence. What you have there in the toroid transformer is a centre tap 36v that is it has 18-0-18 if you were to measure across the 2 blue wires you get 36vac. Each 18vac supplies the rectifiers with a + - dual rail, the 0 "ground". Within that circuit the opamps will need a dual or bipolar dc voltage after rectifying and regulating could be 15 or 18vdc. You should not have tied those two together and supplied only 18v with you variac, tho it won't damage anything it's just an incorrect voltage and won't work.
Hi Glen, i have the same eq, 1 channel working fine the other channel is very low & windy also the level lights are all illuminated with the clipping light with no current going thu the channel. when you increase the 20k slider the 20hz low bass would increase so everything seems all over the place but like i said the audio coming out of channel 2 is very low & windy, can you help??
My electronics background is extremely limited. As an Electrician for 40 years, I understand power supplies and such but deeper into electronics I am left in the dust. Sorry..
Hi I got a dual 31 band digital equalizer and spectrum analyzer and it was working fine and all the sudden its glitcing out and can't control anything anymore any ideas and what I should look for if I open it up I'm great at soldering just don't know what to look for and also could it just be dirty inside because the dust here is insane