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How to Install UX4 Socket without Punch

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Doing my own tube amp chassis is the hardest part of amp building for me. I'm always looking for ways to do more with fewer or cheaper tools.

Mounting UX4 sockets (for 2A3, 300B, etc.) always seems to require a chassis punch to make the mounting hole neatly. These cost $30-60 USD!

I use Klein Uni-bit step-bits for my big holes but the biggest I've found is 1 1/8 inch in diameter. I just found a UX4 tube socket that will fit the 1 1/8 hole I can get with the step bit. I've bought it, and it fits just fine: http://store.yahoo.com/triodeel/77-mip-4.html.

It's a flush-mount Amphenol socket, which has a good reputation. The contact integrity looks good. The contact integrity on the ceramic EF Johnson copies I see floating around looks a little better -- but you need a 1 3/8 chassis punch (really a 1 1/2 inch to be on the safe side).

Note also -- the ceramic Sovtek UX4's sold by the same dealer are a little too large to fit in the Unibit 1 1/8 inch hole, but just a little work with a round file would cure that.
 
Yeah, I also tend to use the amphenol sockets designed for a 1 1/8" hole. Then I can just use the same greenlee chassis punch as for octals. AES sells them.

But for the slightly larger ceramic UX4's from Angela, etc. I have had success using the 1 1/8" punch and then routing out the remainder with a dremel tool. But you must layout the outline first with a compass, for accuracy.

Joel
 
diyAudio Senior Member
Joined 2002
Hi,

Doesn't Triode Electronics sell a complete kit of punchers suitable for all kinds of sockets for about 60$?

I don't remember wether these are Greenlees but for the occasional use I think that shouldn't matter that much.

I've only Greenlee which are expensive but last a lifetime, I can only recommend them.

Like any good tool, they are an investment. You'll thank yourself later on.

Absolutely.

Cheers,;)
 
Doesn't Triode Electronics sell a complete kit of punchers suitable for all kinds of sockets for about 60$?

Yes they do, and the one stepped bit I found that goes up to over 1" was around $70, so at that point the punches are cheaper.

If I knew that I was going to build several amps in my lifetime, I'd invest in a set of good punches with no hesitation. I'm still at the "let's try it and see if I enjoy it" stage, so I want to find a meaningful balance between investing a lot in tools, versus buying cheap tools which would make me spend much more time and effort and I'd end up throwing the tools out pretty soon anyway. The punch set sold by Triode Electronics is probably the product for me, I just want to make sure there aren't any better alternatives for a casual builder.

Also, I don't have a drill press. If these large bits only work with drill presses and not with hand drills, then I need that punch set, no questions about it :)
 
You can get the big Unibits from EBay sellers, new, for $20 or less. If you're only working with 9 pin tubes, the smaller Unitbit does up to 7/8 inch, which is fine for 9 pin sockets. It can be had for $10.

You can't use them on the couch, but they make better holes than a punch, and give you a range from 1/8 to 1 1/8 inches in 1/8 inch increments, for $20. Just put a little cutting oil (or even bacon grease) on the work, and run the drill at low speed.

I wouldn't try to use the big Unibit without a drill press. But, a $50 variable-speed belt drive import job from EBay will do the work just fine -- I've made at least six chassis with mine, in aluminum, copper, and steel -- and is useful for a bunch of other jobs too.
 
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