...ordered a new footswitch from the Switch Doctor on eBay. The amp itself arrived yesterday and ll was not well...at first fireup it immediately began making some hugely loud static-y noises like it was going to blow up, so I put it on standby and turned the volume down. The amp had been rarly used in the 13 years the previous owner had it...maybe 50 hours total, now with the volume down I tried it again, the noise cleared up after a bit and I started to play through it, everything seemed normal except there was no reverb...so I decided a teardown was in order. What I found was pretty interesting...
There were three dead pill bugs covered in spider webbing rolling around freely on top of the printed circuit board! It needed debugging in the truest sense of the word! So I turned the amp upside down and shook the little buggers out, and blew some of my personal hot air
from my lungs in order to hopefully remove any other stowaways and what I hoped would be any dust out from under the PCB, and set the chassis down and decided to remove the reverb tank.
In it I found two multi stranded wires that had broken off at the solder joints on the send side! So I used some solder removal braid to get the excess solder off the tabs and expose a hole in each, stripped a small bit off each wire and resoldered them. Put the whole thing back together and it ROARED!
Bedrock used transformers routinely that were double the required spec for power and output, so the amp was quite capable of getting very, very loud, Mesa loud! It had what appeared to be an Eminence ceramic speaker with the Bedrock name on the sticker rated for 100 watts. The tones were awesome, tight, and the effects loop added a huge amount of easily adjustable gain to both channels as an added benefit, the sound that came out was all about 80's and 90's rock, enough gain for metal tones, i was astounded how such great tones could come out of an amp that had sovtek 12ax7's and sovtek el84's. I think that despite the oversized iron that the whole thing weighed maybe 30-35 pounds, so I now have a relatively lightweight grab and go amp that would keep up with any band's stage volume and then some as well as work perfectly in a quiet room thanks to a well designed master volume circuit, gain settings are preserved at low folumes for the dirty channel. Next step is to use a bias tool and determine what setting the stock sovtek power tubes use and roll some vintage Mullards, RFT, JAN Sylvanias, and 6p14p-ev Russian mil stock to see what will sound the best and also to test the phase inverter for matched triodes and look for some stuff out of my vintage old stock stash for the preamp. This is going to be a really fun, rewarding project! And yes, I'm going to get a cover for that amp!
