SG Systems | SG100 Inspection & Diagnosis
This is a look at a relatively rare SG Systems SG100 hybrid amp from 1973. Built and designed in collaboration between Bob Crook of Standel amps and MSI Systems (Gibson), utilizing a wild pair of 8417 power tubes that see over 600VDC on the plates and 300V on the screens, built in phasor, built in fuzz (maybe??), and hardly any information online about what the heck is actually happening in these things.
This one has super low volume and weird oscillation happening on the low signal that is getting through. Follow along in the video to see what we find and what could be a total nightmare, or an easy fix.
I am posting all of the schematics and info I could find below since it took a bit to track anything down about these amps.
