(New forumite) - Help with switching !!!

[DSV]

Hi all! 1st post here!  And already bugging you with questions 

For my next project (I've made a few stompboxes) I'm going to build a 3 channel preamp for my guitar, and I'm having a bit of trouble with the switching section.
My goal is to have:
- 3 footswitches, each one activating its corresponding channel and deactivating the others,
or
- 2 footswitches, the 1st selecting channel 1 (and deactivating channel 2 or 3), and the second recalling the channel which was in use before selecting ch. 1, and then switching between channel 2 and 3.
Furthermore, this switching system should not need a dedicated power supply.
Finally, the footwitches should, if possible, not be in the same enclosure as the preamp (which I think means I'll have to find a sitable connector between them).

I have only experience with mechanical 2PDT and 3PDT switches, but none with other types, which I think are needed for this. My searches on this forum and other places haven't given good results, basically because I don't really know what to look for. 
I saw there are relays, and also other switching circuits (CD4066?), but I couldn't find some concrete examples or simple tutorials for them.

Have you got a schematic which performs what I need? Or a link to a good explanation about their work?

Thanks,

DSV

[Roobin]

Have a look at GEOFEX.com - IIRC there are a number of digital switchers and relays.

[DSV]

Thanks. I also found some good resources on the ToneGod site.

Basically now I have in mind what I want to do for the channel switching:

                   *--------------- CH1 --------------*
                  /                                               \
in --SW1a                *---- CH2 ----*                SW1b-- out
                              /                     \
                   *-SW2a                       SW2b-*

                               *---- CH3 ----*     

and the LED indicators:

                   *-----------LED1----Resistor----GND
                 /                           
V+ --SW1c                 *---LED2----Resistor----GND
                               /             
                   *-SW2c               

                                 *---LED3----Resistor----GND

This could be done with 2 3PDT footswitches, however I'd prefer a separate 'pedal' for controls.

I think I have understood the general principle behind the switching. However I still have got some points to clarify:
- which is better, the CD4066 or the 4053 ?
- if I use the 4053, can I use the 3rd 'switch' to hook up an indicator LED (basically I'd like to switch between ground and V+) without damaging the circuit ?
- what is better, momentary or latching switches (and correspondinf implementations) ? I can find both kinds of footswitches at the same price.
- the footswitch I'd like to use would be connected with the preamp through a stereo cable, for GND, S1 and S2. Is there a way to add indicator LEDs in the control pedal, without using a battery ?

Thanks,

DSV

[DSV]

I have checked the datasheets of the 4053 and 4066. They both offer the same resistance to the signal path when engaged, so I think there should be no audible difference when in operation.
My choice will then be based on the better configuration. The three channels are basically 3 Sansamp GT2s. I'd like to know which could be the best place in order to add these switches.
Judging from the schematic at Tonepad, I think there are 3 possibilities.
1st one:
- I can 'split' the signal after the 22n cap and 10k resistor (point A), by wiring the 3 GT2s in parallel (fig 1). I don't think this should cause audible treble loss, since the driven impedance is pretty high (~= 100Mohms). So no switch here.
- I can select the channel after IC4b (point B, just before the output buffer), or at the output C (I will add another buffer, in order to have a controllable output line out, or a headphone amp.)

2nd one:
- I select the channel at point A;
- I mix all the channels after IC4b, or the output buffer

3rd one:
- I select each channel both at point A and at the output (like a DPDT switch configuration).

In all these configurations, there is no need for the 1M pulldown resistor at the input.

Which one do you think is best ?

[~arph]

..please delete, was in wrong thread