Thunderbass schem

JC

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Hello. I'm new in this forum and I come asking for a schem for the Guild Thuderbass amplifier.
It is the one that uses a couple of 8417 power tubes.
I have done a long search with no success at all.
If someone can help me, that would be really nice.

Thank you very much.
 

JC

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sfIII, thank you very much.
I couldn't wait for the schem because the amp is not mine, so I rebuilt the output like any 'standard' 6L6 amp, cathode biased.
The output section was completely blown. The bias circuit was also bad.

In fact it is a very nice sounding amp.

Thank you.
JC
 

RWood

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JC,

Did you ever locate a schematic for this amp?
I'm trying to figure out what the correct rectifier tube is for the one I'm working on. This one has 8417s in the power section like the one you were rebuilding.
If no schematic, do you remember which rectifier tube that amp used?

Thanks!


RWood
 

JC

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RWood said:
JC,

Did you ever locate a schematic for this amp?
I'm trying to figure out what the correct rectifier tube is for the one I'm working on. This one has 8417s in the power section like the one you were rebuilding.
If no schematic, do you remember which rectifier tube that amp used?

Thanks!


RWood
RWood,

'mine' was solid state rectified. And that was original.
I could not find the schem for it, so in part that's why I rebuilt it to take the 6L6GCs.
I can't help much here I'm afraid, sorry.

JC
 

RWood

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Thanks for the reply!

Turns out this tube is not a rectifier; it fooled me because it's mounted with the filter capacitors, and it gets a separate filament supply from the transformer.

It's a 6GF7A (twin triode) and it connects to the screens of the 8417s, in series. There is a trim pot connected to this tube, too, maybe to adjust the output of the first triode, as it gets cascaded into the second one.

The tube checks out OK on the tester. I'm just plodding my way through a circuit I've never seen before, and like you, without the benefit of a schematic!

RWood
 

sfIII

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Somehow.. during all of this I have managed to get the schematic for this amp and will email it to anyone who needs it.. Mine is the 6l6 type.

My email is hgault57@earthlink.net... expect to get a message stating that your not in my address book after the first email.


Don

Perhaps we should have a place for schematics here on the site.
 
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