Bogner Alchemist

[Randy 1964]

Hey, my amp is new head and 212 spk cab . Last jam switching from dirty channel to crunch channel, nothing no sound !!! I still had a green light but no sound?I plugged the guitar strait in the amp and took the footswitch out useing the toggle switches to change channels I still had no sound on the crunch channel. So I went back to dirty channel that worked fine so I stayed on that for the rest of the jam. After I unpluged everything, took the back off the amp and checked tubes for looseness, everything looked good. So I pluged it back in and the amp worked fine,"whoa what a releif". I'm wondering if anyone else had this channel switching problem. I hope I didn't by an expensive lemmon because up to now it's be worth every penny!
Please respond if you had these problems or know how to solve them.


thanks Randy

[Sowhat]

The Alchemist has 4 preamp tubes and 1 phase inverter, all 12AX7's Each channel has it's own tube V1 & V2, then it has the tone control amp stage V3 and finally the effects stage V4. In your case, V1 was probably not making good contact and that's why crunch was dead. Wiggleing them to check for a good contact probably fixed your problem. I have fixed one of those myself and bad tube socket connections was it's problem as well. Would probably have been a good thing to clean all the sockets... take a 12AX7 and spray the pins with some deoxit and then insert and remove it a few times for each socket. You can also get microcracks on the tube socket PC solders... reflowing those can perform miracles if cleaning don't get rid of the problem.