My kid wants a Jerry Cantrell amp...

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cstenger5
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Re: My kid wants a Jerry Cantrell amp...

Post by cstenger5 »

GOTCHA!

I was thinking you meant that I'd have to swap out the whole Tremolo TMB V1, which i interpreted as "since there's 2 triodes in V1 of the Tremolo TMB, that means I need to swap that out with the pentode *and* half of another 12ax7 for some reason I'm still too green to understand."
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zaphod_phil
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Re: My kid wants a Jerry Cantrell amp...

Post by zaphod_phil »

There's a much simpler way that doesn't require messing with a pentode (although I actually like pentodes). Just build an 18W TMB amp with the Normal channel's output, taken from the wiper of the Normal channel's volume pot, cascaded into the TMB channel's input, via a 10nF cap. That will give you some huge gain! :D I once did this same mod, known as the "one wire mod", for a customer special order, while I was working with Trinity. Maybe it should have been called the "one cap" mod instead LOL.
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cstenger5
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Re: My kid wants a Jerry Cantrell amp...

Post by cstenger5 »

Well that sounds awesome. I've already started on the EF86 one, but if that mod is as simple as that, I could probably add it to my Mojotone TMB and give that one to him.
Then I'd get to keep this one for myself...

Oh man.

That's got to be the plan.

:D :D :D

Do you have any drawings of that, so I can't accidentally destroy it all with my alternating over confidence and total lack of confidence?
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Re: My kid wants a Jerry Cantrell amp...

Post by cstenger5 »

Would that be normal channel vol wiper -> 10uF cap -> TMB channel input tip?
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JMPGuitars
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Re: My kid wants a Jerry Cantrell amp...

Post by JMPGuitars »

cstenger5 wrote:
Sat 10/09/21 9:37 am
Would that be normal channel vol wiper -> 10uF cap -> TMB channel input tip?
You want to go normal Volume wiper -> 10nF (not µF) -> tube grid input for TMB channel. V1 pin 2 in this schematic: storage/18watt_tmb_JAschematic.pdf

However, I would probably also use 10K grid stopper resistors on both halves of V1.

I suppose you could make it switchable too. Have a switch determine whether the TMB input is cascaded from the Normal channel, or comes from the TMB input instead.
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zaphod_phil
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Re: My kid wants a Jerry Cantrell amp...

Post by zaphod_phil »

JMPGuitars wrote:
Sat 10/09/21 12:35 pm
However, I would probably also use 10K grid stopper resistors on both halves of V1.
I agree. And those 10k grid stoppers (preferably metal film or metal oxide) should be soldered directly to V1 pins 2 and 7 to minimize the chance of radio station interference getting into this very high-gain amp. Likewise, you would need to take great care with the layout and "lead dress", using shielded wire for longer signal connections, as well as "modern grounding"
- viewtopic.php?f=4&t=25372 , to avoid unwelcome sounds like, hum buzz, squealing and whistling 8O
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turtle441
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Re: My kid wants a Jerry Cantrell amp...

Post by turtle441 »

FWIW, if he really wants a Jerry Cantrell amp, look up headfirst amplification. He's a guy out of Australia, has put together a pcb designed for cloning multiple Friedman's, including the JJ Jr. I've got one of the boards sitting on my workbench waiting for the schedule to open enough for me to put the chassis together. It's pcb, but it's 3mm, looks pretty well done.
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Re: My kid wants a Jerry Cantrell amp...

Post by cstenger5 »

turtle441 wrote:
Tue 10/12/21 10:55 am
FWIW, if he really wants a Jerry Cantrell amp, look up headfirst amplification. He's a guy out of Australia, has put together a pcb designed for cloning multiple Friedman's, including the JJ Jr. I've got one of the boards sitting on my workbench waiting for the schedule to open enough for me to put the chassis together. It's pcb, but it's 3mm, looks pretty well done.
Omahgoodness. Need to look that up! Thanks!
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