Tube Amp Archive

I've found the NOS GE power tubes and matched GE 12AT7(6201) to be real good in the BF amp's power section. The price is not too bad. If you can swing for RCA 7025 in the V1, V2, and V4 positions, that's gold. A JAN 12AT7 for V3 and a decent 12AX7 for V5 should get you that Fullerton sound. Yeah, I ...

Yeah, I agree ! I,ve been trying to get a handle on the function and effects of the suppressor and screen grids in a pentode. This thread has been very helpful ! Art

Thanks for all the responces ! Should have been more clear on the application. The amps are '63-'67, fixed bias supplied off a dedicated PT secondary tap. And yeah, it's just a filter cap for a circuit that would see about negative 55 volts at a max setting, but usually a lower opertating level. The...

Always replaced the 25/50vdc caps with 50/100vdc. The wall voltage was my concern. Is this an unfounded concern ? The capacitance change was just a filtering guess, on my part. This would only apply to 2X6L6 power tube models; Super Reverb, Bandmaster, etc... Any comments would be great ! Art

A comparison of the bias section would be the way to see what you've got. Early '68 Band Master amps were still the AB763 circuit. IMO these are great amps. I've had my '67 for nearly 30yrs.

Yeah, I know what you mean about the dull headache. Turned a simple stand alone reverb kit build into a grounding scheme education. Used a piece from this tutorial and that tutorial. But the combination worked out just fine, dead quiet.

Yeah, I would also suspect bad solder joints. I've experienced this with older Fender amps that have developed waves on the board. The waves stretch the below and above board wires and components, enough to break the joints. Although your amp is newer, pushing on the board is kind of doing the same ...

Used a Clubman-35 in the blues band for 8-9 years, just kind of made that leap of faith, that it was indeed what Matchless said it was. Talk about energy spent on heat, at the end of the night the guitar's input plug, at the amp, was almost too hot to hold on to. On another note, that amp sure had s...

Thanks Merlin, I refer to your website periodically, to help with my understanding of amps. Just re-read the tutorial on single ended output sections. Yeah, sounding knowledgable around most folks that come in, wouldn't be tough at all. I was just interested in being able to demonstrate the differen...

Appeciate all of the info. I'm familiar with the Aiken article and a handful of others. Been repairing and restoring the older Fender amps, as a side job for well over 25 yrs. But never invested in a scope. At any rate, guys have been asking me whether or not this Mesa, Matchless, Badcat, etc is act...

Built the Weber 5G15 almost two yrs ago. It's a very good sounding unit.

Thanks ! Art

Just wondering if a ham&egg tech, like me, can determine if an amp is truly operating in Class A, without the use of an oscilliscope ? If there is a thread on this subject, from previous discussions, that would be fine. Thanks, Art

If I can side-track the EL34 subject for a question; Does anyone have any opinions or country of origin, on the mid 2000 GT 6L6GE tubes ? Got a pair I use in '68 Bassman 2X10 conversion combo. They're well over 1200 hrs, and still match within 2ma at idle current draw. It's just that the history of ...

Thanks, Steve. Don't do much amp repair anymore, but I still like to tinker with my amps. Art