Some of my favorite times playing live and recording tones where through an Ampeg G20. A friend had a beat up one, and I adopted it while we played in a band together circa 1990. The G20 I was using had a screw drilled into what was left of the volume potentiometer, bent at an angle. I had a Tele and a Rat pedal. That's it.
We played hard core punk music in frat houses and dirty clubs in VA. At the fraternity parties, we where often shut down mid-set. The police would show up, and we'd watch the crowded house party empty. Then we'd pack up P.A. and backline back into the van. Having a portable combo based guitar rig was key. You don't get paid to play Hard Core, and you never know when you might need to evacuate.
So this little guy replaced a much larger half stack whenever we played places we needed to provide P.A. for. I liked the tone so much that I used it to record a demo. I remember the vibrato being quite severe, reminded me of a helicopter.
A few years ago, I tried locating the original amp, I wanted to experience the crunchy, thick, responsive tone I loved back in the day. A friend has it in Chicago; it's missing speakers, needs a complete re-haul. Then just a few weeks ago, I find this one NOS in a liquidation sale here in Milwaukee. My amp tech replaced filter caps, added a grounded cord, and now I can time travel back to 1990, smell the frat party potpourri again. Ah, the intoxicating, delicious combination of spilled beer, cigarette smoke and sweat, all blended together in a van full of punks.