Adding 3-Way Switch for Tone Bypass and Bright Bypass

[MarkF786]

I have an amp with a 5F2A-like tone control:



I'd like to add a 3-way switch to do the following (in no particular order):

- Tone Pot and Bright Cap (C1) Enabled
- Bright Cap (C1) Bypassed
- Tone Pot and Bright Cap (C1) Bypassed

I drew a diagram out on paper that I think would work; I tried to find a schematics tool that to use on my Mac to draw it, but didn't have luck. Since I can't share a schematic, I'll try to explain what I'm thinking. Obviously I'd be using a 3-way DPDT switch, but I think I'd need to use an "on-on-on" switch that works like figure D below in the center position:



So my plan is to have one leg of the switch toggle the connection to the top of C1, and the other leg of the switch toggle the connection to the middle terminal (2) of the tone pot. This should create the following switch positions:

- Tone Pot and Bright Cap (C1) Enabled - the switch would have both connections "closed"
- Bright Cap (C1) Bypassed - the switch would have the connection to C1 "open" and the connection to the tone pot "closed"
- Tone Pot and Bright Cap (C1) Bypassed - the switch would have both connections "open"

My questions are:

1. Would this work, ie. would having "open" connections at these points properly bypass the components, or is it not good to have "dangling" connections like that?

2. Is there a more efficient way to wire it?

I know other people have done this mod before but I haven't found a schematic, and also I've seen different switching options (for example, "On"/"Off"/"Bright") which makes me think there are other ways to wire it.

Thanks for your advice!

Kind regards,

Mark

[loudthud]

The open connections usually don't pose a problem. Just locate the switch near the pots.

[Groover]

I disconnected the tone control in my 5F2a build at one point, and frankly I didn't hear much difference compared to when the control is at (electronic) mid sweep. You might find that the bright switch is all you actually need. Of course YMMV.