Guitar Amp Help Needed....

[zozoe]

Greetings ampoholics~ I need a hand with this here guitar amp. It was made by a renowned SF, CA company... It works fine & sounds great, though i have yet to crank it..... 2-6V6's, GZ34, 2-12AX7's & 1-12T7....
The only strange behavior thus far is that the Mid control, that when brought down, the most of the amp sound goes down, AND the Bass control has very little affect. (Tone pots are 250K, 100K & 250K) I've labeled all the relevant pots & parts~
My main questions, which the builder was unable to answer, was 1) There's that lone 9pin tube socket that, according to builder, was not being used , especially "if there was no 7th tube included",,,,,
2) It seems that the red reverb pot & tank connections are hooked into the middle 12**7 slot, so should that not be where an AT7 might go??

I know enough, being able to eyeball which is the 1st AX7 Pre, & is the 3rd pre slot is the tone circuit, & what would or should be another AX7?? It's a clear snapshot, so enlarging it show enough, i believe. That's a bias trim pot adjacent to the 2 power tubes? Is that Mid pot value, 100k, the reason I'm getting that volume suck as i go below 12:00, the way my Boogies do when you turn all the tones down?
And that lone 9pin, which to me seems to be boarded up & shut down but still connected to the other pre's?? Any risks to having all AX7's? I want the most possible gain, the best Reverb return level.....

A million & one thanks, folks, & be well~
ॐ

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[Stevem]

Question.

How is it that from what I can tell from all your post you come into having all these amps that you start off by saying you like the sound of and are happy to have , yet you get into how you don’t like it?

You do this same type of posting on another amp web site I have seen you on.

[zozoe]

Answer;

Where is it that I said I didn't like it? My questions are solely education & furthering my knowledge base, especially if something seems amiss or confusing with whatever amp I bring to the table....
but did I not say "it's a great amp!",,,, right??

I'm flattered that you're following my chat travels, but any answers & info I'm seeking could easily have been handled in the same time as 'this'..... I come seeking only clarification & a few answers, & if you cannot help, at least be supportive.... After all, isn't that what all these chat rooms are all about? thnx

[Stevem]

More then anything else I am very very curious.
It seems like every two weeks your posting about a different amp you have come into possession of that’s all.

[zozoe]

Very, very curious? PM me if you wanna know more... But in the chats, are we not here to assist & somewhat educate & share knowledge?? The chat is for more important stuff than your curiousity or my a.a.s....
We're good ~

[Stevem]

Getting back then to your circuit/ amp question, what is the value of that mid pot and the cap soldered to it?

[GAStan]

The green wires to the mystery 9 pin are for the heaters. If you plug a tube into it the heaters will glow but the tube will do nothing more than draw heater current.

Have you drawn a schematic for this amp? Would be helpful and you might find the problem.

[TUBEDUDE]

V2 looks like reverb return. The verb looks like it take the input from the power tube.

[zozoe]

Getting back then to your circuit/ amp question, what is the value of that mid pot and the cap soldered to it?

Thnx SteveM,,, the MID pot is 100k & the other 2 are 250k.... I'll have to pull the chassis again to get you the cap value, but the builder, unwilling to divulge too much into, said "It’s a fender curve but the mid is more aggressive. If mid is at 12oclock or more the hi and low are less effective. Try turning mid all off and adjusting hi and low." When I turn the MID down, as he proposed, I lose practically all signal, & when i turn it up, i lose 90% of treble & bass control.... It's a MAJOR MID boost as well as a signal killer on the other end.... As I also mentioned, when the volume is up past 7 or 8, the reverb dies off,, but it's strong & long at moderate volumes..... thnx
Kenny ॐ

[zozoe]

LASTLY, is it at all possible to get 30 watts out of
2-6V6's, GZ34, 2-AX7's & 1-AT7? Don't forget, the amp came with those unmarked & OVER-sized 6V6's, & may very well have been, or was supposed to be 5881/6L6's??...
An uninforming builder is my biggest obstacle, along with my limited chassis experience, but undying quest for knowledge..... thnx again all~

[Stevem]

If you have a 47k resistor strap it across the outer lugs of the mid pot and see what that does for you.

[TUBEDUDE]

LASTLY, is it at all possible to get 30 watts out of
2-6V6's, GZ34, 2-AX7's & 1-AT7? Don't forget, the amp came with those unmarked & OVER-sized 6V6's, & may very well have been, or was supposed to be 5881/6L6's??...
An uninforming builder is my biggest obstacle, along with my limited chassis experience, but undying quest for knowledge..... thnx again all~

No. Well maybe in class C.

[Stevem]

Or in class AB2, but yes, no 30 watts in class AB.

Those tubes you posted a picture of are for sure not a 6V6 type, so now the question is what impedance is that output transformer made for with a 8 ohm load.

[Stevem]

To be fair, in reference to my comment above if one was to run JJ brand 6V6 outputs with 450 volts on the plate ( and they can handle more) then yes 30 watts could be had.

[zozoe]

Yeah,, I've got a bunch of JJ's around, and at this point I'll gladly hand it over to my new tech who recently built me a mean-ass 5E3 Tweed.... It's evident that my lack of firsthand, under the hood tweaking experience preceeds me, so thanks for your patience, enlightening tips & thoughts on this project, & I forsee a nice amp in the end.....
ॐ