Insulating the Input Jacks, Pt. 2 - Tweed Bandmaster/Super Clone

You may have noticed a bit of a break in the action on the amp build.  That was due to the fact that I was trying to figure out a way to insulate the input jacks from the chassis.  In the last post, I described how I took a stab at using a liquid insulation paint to paint the inside of the holes in the chassis.

To make a long experiment short, it didn't work.  The real issue is that the holes for the jacks (3/8") is so close to the jacks themselves that the insulating paint just scrapes off.  Another approach was needed.

But what to do?

I could go with a Cliff jack, as used on Marshall and Vox amps,  which is plastic and therefore insulated.   But this amp is a tweed-style and I really wanted to stick with Switchcraft.

After some pondering and research, I sussed out how to do it.  I needed to open the input holes up more so they could take a shoulder washer.  The picture above shows the inputs reamed out to 1/2".  Not perfectly pretty, but no-one will see them on the finished amp.

Since there will be a washer in place, the standard length thread on the jacks is too short.  So I'm putting in Switchcraft 12B jacks, which have an extended thread.

This is a test fit of a washer on a jack.  You can see the 'shoulder' that will lie inside the jack hole.

Here's part two of the test fit.  The shoulder keeps the jack from touching the chassis and being grounded.  Fender did not mount their jacks like this, but since we're going to connect all the input grounds to one location, we don't want them to touch the chassis and set up a potential ground loop.

I hope this is worth it.

And finally, a second shoulder washer and the mounting nut in place.  Covers up the slightly ragged hole, and looks pretty good.

This is how all of the input jacks would look IF I was going to use an insulated washer on the outside like this.  But I have other plans!  Bwahahahahaha!

Choo wait, comrades, and see vhut I haff planned!