fix shorting to aluminum case, ideas for newbie

[gychang]

I am trying to add volume control and 2 input using DPDT 3.5mm jacks, on a t-amp clone.

The problem is aluminum back panel is conducting-shorting the input signal, speaker output etc. What is the easiest solution for this newbie? Spray on the rubber compound?, hate to order all new jacks or change to a thin wood back panel.

thanks,

[Buckapound]

Many jacks come with plastic washers that will insulate the conductive parts from touching the metal case, and of course, fully insulated versions are available.

You can achieve the same effect by creating your own insulating scheme. A layer or two of heat shrink on the barrel of the jack, plus small plastic washers on each side, and that ought to do it. You may be able to find plastic washers at a hardware store, but they're easy enough to make from any kind of plastic, such as a milk jug or soda bottle (plastic on the caps are about the right thickness), cut our with a leather punch or an X-Acto knife.

--Buckapound

[gychang]

Originally Posted by Buckapound

Many jacks come with plastic washers that will insulate the conductive parts from touching the metal case, and of course, fully insulated versions are available.

You can achieve the same effect by creating your own insulating scheme. A layer or two of heat shrink on the barrel of the jack, plus small plastic washers on each side, and that ought to do it. You may be able to find plastic washers at a hardware store, but they're easy enough to make from any kind of plastic, such as a milk jug or soda bottle (plastic on the caps are about the right thickness), cut our with a leather punch or an X-Acto knife.

--Buckapound

thanks so much for your ideas, they are great and will try it.

[DF96]

Normally sockets are arranged so that, if not insulated, the grounded outer part should be grounded anyway. This can mix up signal and safety grounds, so create hum and noise problems, but it should not ground the signal itself.

[Andersonix]

And the fact that you mention shorting the speaker outputs using the binding posts shown in the pic indicates that you are somehow not mounting them in the 'correct' size holes?

[italynstylion]

I use the same binding posts and mount into aluminum. Here's what I do.

1) Cut a short piece of heat shrink sized just a little longer than the aluminum is thick and the diameter that will shrink down onto the binding post.
2) Slide it on and shrink it down.
3) Mount the binding post.
4) Never worry ever again.

[italynstylion]

You can also get some rubber neroprene washers at Lowes in the hardware and screws aisle. They're in the drawers with the specialty items. Very easy to find and work quite well.

[allentodd]

Originally Posted by Andersonix

And the fact that you mention shorting the speaker outputs using the binding posts shown in the pic indicates that you are somehow not mounting them in the 'correct' size holes?

+1

Rather than making the holes in the aluminum the size of the binding post, look carefully at the plastic part of the binding post and there is usually a slightly raised circle that is about 1/2 inch in diameter. Make sure your hole is big enough for that circle to fit and it will hold snugly with no chance of shorting.

[gychang]

Originally Posted by allentodd

+1

Rather than making the holes in the aluminum the size of the binding post, look carefully at the plastic part of the binding post and there is usually a slightly raised circle that is about 1/2 inch in diameter. Make sure your hole is big enough for that circle to fit and it will hold snugly with no chance of shorting.

Yes, I noticed that, excellent idea for this newbie.