switch between two amp-inputs, multiple channels

[gazzary]

Hi,

I want to build a footswitch that allows me to do the following:

4 input channels (mono, left-right from two keyboards)
8 output channels (idem, but twice) 4 A and 4 B
switch to select A or B
prevent popping, humming, and other unwanted sounds while switching

I have searched the internet for schematics without much success. How should i built one of these? what parts do i need?

I have soldering experience, but limited electronics knowledge.

I have added a drawing of what i want.

thanks for your advice.

Gazzary

[AndrewT]

Hi,
signal relays would do it, but probably need care to avoid clicking due to DC on the unconnected poles of the switches.
Try experimenting with a single channel feeding two outputs that are connected up. Switch over with a toggle or similar controlling a single relay and listen if that is acceptable. I suspect not and need a bit of development.

[gazzary]

A long search yielded the schematic on http://www.tubefreak.com/customab.htm. This is a schematic for a one - to - two channel setup. I think this will probably work (but still have to try).

I would like to 'multiply' this setup by superimposing 4 of these, all connected to the same battery and switch. Can i do that or do i have to include diodes of some (which?) sort to prevent unwanted currents?

Also, if i do this 4 times, will the 9Vbattery still support that (for at least 6 hours...)?

Any feedback on this schematic and the plausibility of it working for what i want to do is very welcome.

Thanks for your replies.

Regards,

Willem Kossen

[AndrewT]

That circuit does not solve the problem of an audible click on changeover if a small DC voltage has built up on the unused output.
It is just a relay switched change over.

But, try it to see how good/bad it is.
You may be able to tolerate the click if the audience cannot hear it for the noise coming through.