This 1U Peavey preamp came over for a retube since it sounded weak. I had never even heard of such a preamp and holy smokes it has a very nice distortion for hair rock!
I installed a new set of tubes, Tung-sol 12ax7 for V1 and V2-V4 JJ EC83S and tried how it sounded. More punch definitely but could have a bit more character. After a lot of tube swapping I settled for JJ EC83S in all other positions except V2 where I used a Sovtek 12ax7lps. Much more mesa-like breakup and fuller sound. While it was open I cleaned the pots and jacks and checked the caps, everything was ok there.
If you find one of these on ebay, fleamarket etc. for cheap I recommend to buy it, you might be positively surprised! And hell, who wouldn’t want to own a ROCK MASTER! :)