Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: fossilshark on January 09, 2017, 06:58:46 pm
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I ordered this JTM45 chassis off ebay (my attempt at making a chassis failed horribly) and i plan on building a JCM 800. The holes for the tube sockets are already cut and so are the control panel holes, but not the transformer holes. This is how i plan on spacing the power tranny/choke/output tranny and the output tubes are in to show where theyll go. Do i have any risk of magnetic coupling in the trannys this close? Im not worried about stray AC interference as i plan on making sheet aluminum covers to go over the transformers. Any problems? Also im doing the electronics on terminal strips so i need the room in front of the tubes.
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... This is how i plan on spacing the power tranny/choke/output tranny and the output tubes are in to show where theyll go. ... im doing the electronics on terminal strips so i need the room in front of the tubes.
If it were my amp, I'd swap the positions of the choke & OT (I'm assuming the smaller black lump is the OT).
I'd also move the OT to be centered on the output tubes, or aligned with the tube furtherest from the PT. I hear what you're saying about the terminal strips, but I'd be thinking about either having the head of the bolt inside the chassis (coming up from under), or using short bolts which are only long enough to allow the nut to get enough threads to hold on.
Or I'd consider using a single bolt to hold both the OT and a terminal strip (I've done that trick a few times). Might only apply to one or two bolts, but solves the issue at hand.
Layout is all about thinking a lot in 3-D. Unless you're using a drawing program where you can accurately dimension parts to scale, you might want to hold off layout until you have all parts in hand to see which way the fit together best...
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If it were my amp, I'd swap the positions of the choke & OT (I'm assuming the smaller black lump is the OT).
I'd also move the OT to be centered on the output tubes, or aligned with the tube furtherest from the PT.
.....you might want to hold off layout until you have all parts in hand to see which way the fit together best...
Yep, yep and yep. :icon_biggrin:
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There are plenty of pictures of known working layouts on the net. Take a look and copy.
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Thanks, i will look at some other layouts and i think i will move the OT the way you said, i didnt think about that until just now.