OT: SPDT channel switching for an amp?

[smoguzbenjamin]

How would you go about doing this? I would like to be able to incorporate a footswitch in my amp with a single stereo jackplug, but I haven't the faintest about how to do it. Would a relay be a good idea or not?

[petemoore]

Most of theses newer amps channel switching is done by running two wires///connected is one channel disconnected is the other....the simplest open/closed switch decides.

[smoguzbenjamin]

OK cool, how would I go about using that?

[Xlrator]

Read this thread. I think it will be helpful.

http://www.diystompboxes.com/sboxforum/viewtopic.php?t=19062

[smoguzbenjamin]

Yeah that was about making a footswitch for a channel selector, I know how the footswitch works I even helped in that topic. Now I want to know how the channel selector works and maybe make my own

[Triffid]

Hey Ben,

In the midst of rebuilding the distortion for my Fender Princeton 112 Plus, I also had a look at the foot switch.  The foot switch itself is somewhat different then the one you posted in that other thread, it seems to be able to use LED's without a battery in the switch.  It looks like there's a dual IC (4560, U6 in the schematic) to control the channel and reverb... I think?  It really doesn't make sense to me yet.

Here is the link... take a look at the middle left  portion for the foot switch
http://www.mrgearhead.com/faq/schematics/fender/Princeton%20112%20Plus%20Sche3BB.pdf

[smoguzbenjamin]

Cool thanks triffid

[The Tone God]

I remember working on some modern-ish Fender amps with channel switching. It was fairly interesting what they were doing. It sent out an AC signal to the footswitch which contained a pair of diodes pointing in each direction. The footswitches engaged one of the diodes effectivly rectifiying the returning signal. Depending on which part of the signal is rectified the amp could tell which switch was engaged thus switching that function on.

I wouldn't be surprised if they still do a similar thing. If not this is still a neat way to get two switches working off a two conductor cable.

Andrew

[Triffid]

I think that is exactly what is happening in the above schematic.  Sounds like a fun thing to learn... to bad I don't have a DIY amp yet to try it on.

[smoguzbenjamin]

I also read an article on how to use a CMOS switch with a momentary switch. Maybe that's an option. I'm working on the final final schematic (it's like revision 14 now) and I thought that this would be a nice feature to use. I can't find that CMOS switching article though