Ideas for Mounting Power Transformer

Blue82DC63

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I am in the early stages of building RobRob's Bassman Micro EF86. I am using an 18 Watt Marshall style chassis like this:


and the Hammond 270AX power transformer:


The transformer is significantly smaller than the PT cutout in the chassis. Does anyone have ideas for how to mount the transformer in this situation? Preferably something that can be accomplished by a mere mortal?

Thanks for any ideas.
 

King Fan

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Doug Hoffman has some method where he uses 8 big wide fender washers (not Fender washers 🙂) to 'reach out' and sandwich the existing cutout corners. Dead simple if the reach and grip are right.
 

schmee

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Yeah, fender washers often will work. You may have to cut one side partially off to clear the tranny though.
I made a plate for one amp:
005.JPG
 

schmee

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Thanks for the suggestions. I'll look into them. @schmee your solution looks great. What did you use to cut the plate?
It was just a piece of 'aged' sheet metal off an old organ reverb tank. I used tin snips to rough it out of a bigger piece, then I cut it with a hacksaw inside after drilling corner holes and my bandsaw on the outside where I could.
If your tranny is only a bit smaller than the cutout, the fender washers work just fine.

Any way you go, tin snips are good to have around and cheap.
 
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Blue82DC63

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It just occurred to me that this model of power transformer mounts on the top like an output transformer. It just needs four screw holes and two more holes for the wires. It doesn't need a large cutout. So, I'll just get a small piece of aluminum and drill holes in it. That will be easy enough.

For some reason I was slow to notice that a cutout was not required because I just had it in my head that one was needed.
 

Mowgli

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It just occurred to me that this model of power transformer mounts on the top like an output transformer. It just needs four screw holes and two more holes for the wires. It doesn't need a large cutout. So, I'll just get a small piece of aluminum and drill holes in it. That will be easy enough.

For some reason I was slow to notice that a cutout was not required because I just had it in my head that one was needed.
You still have to cover the cut out in the chassis. I like Trevorus’s idea for that, too.
 

King Fan

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It just occurred to me that this model of power transformer mounts on the top like an output transformer. It just needs four screw holes and two more holes for the wires. It doesn't need a large cutout. So, I'll just get a small piece of aluminum and drill holes in it. That will be easy enough.

For some reason I was slow to notice that a cutout was not required because I just had it in my head that one was needed.

Good plan. With my build in that .08 alu chassis, I made a plate out of considerably thicker aluminum. Too thick. And you don't need much -- I recall finding small sheets of aluminum on eBay, and wish I'd gone with the thinner stuff. If you just cover the cutout and bolt holes, I imagine 1/16" would be thick enough.
 

dogmeat

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I've made a few chassis out of .040 aluminum & they worked fine. it was 2024T3 aircraft stuff though
 




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