Wreck into a 17-inch JTM-size chassis?

[ViperDoc]

I have a 17-inch, un-drilled, un-welded JTM-sized aluminum chassis I am considering for a Wreck build. Any problem hovering part of the power supply board over the open PT cutout, or is that verboten? It is 2 inches shorter than the spec chassis. I could custom order one, but I'd rather not.

[xtian]

I think I understand you. You certainly don't want people poking their fingers into that PT cutout, so you should patch over it with a snip of aluminum.

[ViperDoc]

Thanks, xtian. The Trainwreck layout I’m looking at places the preamp board and power supply boards to the side of the PT chassis cutout such that there is nothing over the PT bell, and the OEM chassis spec is 19 inches long to allow that. If I use a 17 inch chassis, I figured I could slide the power supply board location over where the PT bell is, but it would overlap and bring the supply caps directly over the PT. I’ve seen Friedman amps do that, and I could also spec a standup PT to make more room. Maybe I’ll have to do that.

[ViperDoc]

This is like what I mean.

asteroid_layout_12_107_491.pdf

[DaveMon]

I did this before.....it was not fun......lots of shorting issues ......https://ampgarage.com/forum/viewtopic.php?t=18094]

But nobody has ever seen this much power in such a small chassis!!

[Colossal]

I did this before.....it was not fun......lots of shorting issues ......https://ampgarage.com/forum/viewtopic.php?t=18094]

But nobody has ever seen this much power in such a small chassis!!

Dave,

What do you mean by shorting issues? No components should be shorting against the chassis. Are you just saying that it was very cramped to work in, or did you experience oscillation which was incurable, or both? A Trainwreck Express chassis is 17"L x 8"W x 2" high where the JTM45 chassis is 6.5" W, but with an extra 0.5" in height. Plenty of Express clones have been successfully built using cap cans.

[M Fowler]

I actually enjoy using Marshall blank open channel aluminum style 18W chassis for my Express combo builds.
The blank Marshall 17 x 6.5 x 2.5 chassis would work well too.

Mark

Express Combo No.2.jpg

[ViperDoc]

I've tentatively decided to have a custom chassis made for this amp. The depth of the JTM-style chassis is one concern, owing to the additional power supply height required for this amp. I've had trouble finding a custom chassis maker who will respond to email. I did get in touch with someone who makes what look like robust custom chassis', but with an L-bracket construction style. Any problem with this?

Assy 4.jpg

[DaveMon]

Sorry for delay....Yes, i felt it was very cramped ....the cap stacks were the toughest to position...

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