Is there a schematic around, or even better, a lay out diagram, for converting a Matchless Hot Box to true bypass. A friend of mine some time ago installed a bypass, but this is not a true bypass. I do have a 3PDT switch.

As far as I know, the Machtless Dirt Box is a Hot Box witha true bypass (+ a middle tone knob). Is there is Dirt Box around. I could not find any on the internet.

Thanks
Ulrich

Converting that is very simple. Take the signal wires from the the input and output jacks and disconnect them. Then install a DPDT switch similar to True Bypass #2 as shown here: http://www.diyguitarist.com/PDF_Files/GCI-TrueBypass.pdf
You're basically going to add a couple of wires to do the conversion.

I don't know if the Hot Box has an LED indicator or not. If it does, then you may have to rewire that a little bit and probably use a 3DPT switch instead.

Hello Paul

Thanks for your answer. But I think that it is quite a bit more complicated with the Hot Box (which is a real tube preamp, just built as a stomp box), as quite a few connections need to be switched on or off, as far as I know.

A schematic can be found here:

http://www.geocities.com/j4_student/hotbox.jpg
http://www1.korksoft.com/~schem/newamps/matchless_hotbox.pdf

Looking at the schematic, I don't see it as complicated at all. Just break the connection to the input and output jacks and you will accomplish what you want. You might need to install a grounded circuit input style of true bypass because the circuit may oscillate with nothing loading the input of the first stage of the preamp tube. You can keep the grounded input jack, too.

It worked. Thanks very much.

Ulrich

Glad to be of service.