gbfun
Wholenote
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Posts: 463
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Post by gbfun on Jul 6, 2022 4:19:34 GMT -5
LTB...a free tank of gas would boost the price up to $999.99.  |
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Post by bluzcat on Jul 16, 2022 19:44:11 GMT -5
I’m looking over an amp for a friend and I was substituting preamp 12AX7s. It seems that every spare one that I have is microphonic, including a NOS GE I got from KCA…that one hurts. I’ll save them to go into some other application like PI etc.
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pdf64
Wholenote
Posts: 557
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Post by pdf64 on Jul 20, 2022 4:11:04 GMT -5
Combos can be a pain for that, especially if they’ve got gainy preamps and / or are loaded with high sensitivity, big magnet speakers. I’ve moved to separate head and cab, less trouble with microphonics and easier to move around too.
Almost invariably it’s just the socket for the input stage that’s the problem though, the same valve in the next one along may well be fine. Don’t necessarily have to relegate a valve that’s a bit microphonic to the phase splitter / trem oscillator.
If it’s a master volume preamp, it’s the later preamp stages where the overdrive happens
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Post by Leftee on Jul 20, 2022 5:41:53 GMT -5
I’m looking over an amp for a friend and I was substituting preamp 12AX7s. It seems that every spare one that I have is microphonic, including a NOS GE I got from KCA…that one hurts. I’ll save them to go into some other application like PI etc. Was it, perhaps, a long plate tube and was it in V1 of a combo that you found it microphonic? What Peter says, above, is spot-on. |
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Post by bluzcat on Jul 20, 2022 7:02:45 GMT -5
So thinking maybe just retention the socket? And it is a MV amp- Peavey Classic 20. Not sure on the long plate, will have to check. Thanks!
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pdf64
Wholenote
Posts: 557
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Post by pdf64 on Jul 20, 2022 7:56:50 GMT -5
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Post by bluzcat on Jul 22, 2022 15:44:27 GMT -5
Thanks for the schematic. It just has a pronounced hiss in V1 (no hiss if you pull the tube). Don’t want to derail the thread. When I pull the chassis may post about it in the amp repair section.
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Post by samspade on Aug 15, 2022 17:50:54 GMT -5
Has anyone received a D'Addario survey about tubes? Seems like they may fill the void if they're considering production. Of course, this will be in the USA, so more expensive, but probably worth it considering some of the sources now |
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pdf64
Wholenote
Posts: 557
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Post by pdf64 on Aug 15, 2022 18:33:27 GMT -5
Has anyone received a D'Addario survey about tubes? Seems like they may fill the void if they're considering production. Of course, this will be in the USA, so more expensive, but probably worth it considering some of the sources now What are they asking? Do they indicate what exactly they’re looking to do? Is it anything to do with what Western Electric are planning (to restart making common guitar amp valves in the USA)? Or are they just looking to rebrand Chinese / Slovak / Russian made valves? |
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Post by samspade on Aug 15, 2022 19:47:14 GMT -5
Some questions were if you would be likely to pay more for a tube if it was manufactured in the USA, how many amps owned, tube types, retube freq. So I don't think they're rebranding. I have a few tube amps, actually the only kind I own, and I would pay more if made in USA.
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Post by reverendrob on Aug 16, 2022 7:13:57 GMT -5
They might be rebranding somebody else's USA-made stuff at that point, say marketing and buying out the Western Electric "guitar amp" stuff as distributors et al.
NY state tube manufacture startup would be hell with the environmental regs.
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Post by funkykikuchiyo on Oct 9, 2022 9:46:51 GMT -5
This popped up for me this morning. I can't confirm or deny anything in it, but it is really interesting:
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Post by Peegoo 🏁 on Oct 11, 2022 15:46:02 GMT -5
Tempest in a teapot!
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Post by Leftee on Oct 11, 2022 17:54:57 GMT -5
A giant nothing-burger.
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Post by kito75 on Oct 18, 2022 18:51:52 GMT -5
I think that this guy's list of tube manufacturers sounds about right (not a long list). Probably also right that there are enough tubes floating around to supply us for the rest of our lives. it's just that Murphy's Law still seems to be in effect, so...
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