CW Guitar Audio

2010 Diezel VH4 retube/service. First time in 3.5 years I got a little time to work on my own gear. This one just got a quad of JJ KT77 tubes, bias, and a dusting off. Experimented over a few years with different power tubes in it and settled back on the 77’s after trying everything else. If you focus in on the preamp you’ll see that every VH4 except for a few are built on a board that doesn’t accommodate all the components as if each is a prototype although they are all the same unmodified amp. Just an idiosyncrasy as all other models are built on a fully designed PCB.

Mesa Mark V had broken power tube bases stuck in the sockets from being installed incorrectly and a non-functioning reverb. Got the tube base pieces removed, new tubes installed, checked everything over, and found the reverb fault. The reverb failure was caused by a transistor in the switching/muting circuit. With some skill, was able to replace it through a preamp tube socket opening rather than removing the whole board and front panel controls which could lead to another hour of labor.

Orange Dual Terror was damaged in shipping breaking all toggle switches and 2 pots. So all switches were replaced then the board was removed to replace the broken pots.

1968 Fender Bandmaster “drip edge” service complete. Came in with a loud hum and non-functional tremolo. Was worked on previously by another tech who didn’t resolve the issue(58 year old electrolytic capacitors, cooked power tubes, broken solder joints). So the amp received a full recap of all electrolytic capacitors, new plate resistors, grid stoppers, screen resistors, rebuilt bias circuit, new rectifier diodes, power supply resistors, new power tubes, correct bias, a new power cord correctly wired, and corrected grounding. New filter caps not pictured as I got too excited to start on the next amp.