ProCo Rats repair

Got two Rats of different generations on the bench for repair. The v2 to the left, not working at all. The other one did not reach unity gain.

ProCo Rat
ProCo Rats
ProCo Rat
ProCo Rats guts

I had to replace a malfunctioning jfet source follower on the output stage on the old Rat.

ProCo Rat
Non working jfet transistor

The other one had already been messed with. There were several copper traces on the circuit board that had to be mended, the opamp was burnt and wires not connected. Managed to bring it back to life again.

ProCo Rat
ProCo Rat V2

/Krister

Lady Dirt

Finally had some time to mount the hardware in my new tube pedal design, Lady Dirt. Strange how every build sounds so much better boxed up with some nice graphics.

High voltage tube pedal Lady Dirt
High voltage tube pedal Lady Dirt
High voltage tube pedal Lady Dirt
High voltage tube pedal Lady Dirt
High voltage tube pedal Lady Dirt
High voltage tube pedal Lady Dirt
High voltage tube pedal Lady Dirt

Earlier posts post1 post2 post3

/Krister

Morley Bad Horsie VAI-1 repair

Got this one in for repair

Morley Bad Horsie VAI-1
Morley Bad Horsie VAI-1

Led would not lit at and it did not pass any sound. Opened it up and took some voltage readings. It did not get any coltage due to a bad battery clip.

Morley Bad Horsie VAI-1
Morley Bad Horsie VAI-1 circuit board

After replacing the battery clip it powered up but the led L1 would not lit. Turns out the led was damaged. Had it replaced and adjusted so the circuit would go into bypass mode when the foot is of.

Morley Bad Horsie VAI-1
Morley Bad Horsie VAI-1 L1 replaced

I like the way that the bypass circuitry is built. Never seen a led/ldr combo used with a hex inverter to control the switching fets, works fine on a wah pedal.

Also fixed some new screws for the bottom lid, the old ones where missing.

/Krister

SubZero TUBE-H5 repair

Got this one in for repair, would not make a sound.

SubZero TUBE-H5 repair
SubZero TUBE-H5

Sometimes it’s an easy fix, when opening the back I found the 12AX7 preamptube at the bottom of the chassie. Just put it back in place and it was ready o rock.

I opened it up and took a look at the circuit. Besides from the single 12AX7 preamptube and the EL84 power tube there’s two JRC4558 opamps on the circuit board, so what we got is a hybrid of solid state and tubes.

SubZero TUBE-H5 repair
SubZero TUBE-H5 circuit board

/Krister