Hey, Cap'njuan!
I just happened across this. Has it already been scrutinized here at LTG?
Guild Thunderbass Head
I just happened across this. Has it already been scrutinized here at LTG?
Guild Thunderbass Head
capnjuan said:The amp's biggest virtues are its big clean output
Hi Dane: always risky trying to diagnose via the ether but generally when power supply caps start to fail, they leak DC to ground which is picked up by the audio circuit and amplified as hum. Not saying it isn't the caps but for diagnostics, I'd suggest the 'Get Lucky' approach. Starting with a known good 12AX7, switch it in/out to determine whether one of the preamp tubes is f'd up. If all good and a known good 7247/12DW7 driver tube available, same thing. If all good, then same for the output tubes. If lucky, then it's a tube and all is good. Among other ailments, hiss is also a characteristic of a failing resistor the fix for which requires intervention with a meter and possibly a soldering iron. Try 'getting lucky' first... :wink:danerectal said:What does one do with a Thunderbass that sounds like a hissing cat? I played King_pizza's at one of our last shows and toward the end of the night, it was having a whole lot of trouble staying focused. My guess caps or power tubes, but I'm guessing you guys have more experience.this is why I ask.capnjuan said:The amp's biggest virtues are its big clean output
capnjuan said:If all good and a known good 7247/12DW7 driver tube available, same thing.
Is Marguerite a local girl?danerectal said:Otherwise it may have to see the inside of Marguerite's
capnjuan said:Is Marguerite a local girl?
"Working on mysteries without any clues....' Bob Seeger Hi Dane; default's right; time for intervention by a qualified meter operator. The power supply generates all kinds of voltages for the output tube; primary B+, screen power, and bias as well as supplies to the preamp and driver boards; one, several, or all of these sources could be off.danerectal said:Rats, I could have sworn I posted a reply here... made every ... tube swap ... no positive results...I did notice that the power tube on the right (from behind) had a strange blueish glow as soon as it was warmed up.... I tried a half dozen power tubes that should've had no problem and all of them reacted the same way.