#1
Anyone got some advice on building a cheap and effective passive A/B switcher? I don't need LED etc, just a simgle stomp switch to swap between two outputs.

Going to use it as a solo boost - I'll have one output going to each channel of my amp, so I've basically got two switchable master volumes.
Was hoping to build a quick 'test' one out of old spare pedal parts I've got lying around, to see if it's effective in a band context before making/buying a nicer one.

What I've got:

-Pedal enclosure
-A few 1/4" TS input jacks
-SPDT switch
-Odd bits of wire etc


Will a simple AB work or will I end up with ground noise bleeding from the non-selected channel? Any tips?
#4
Quote by kyle62
Will a simple AB work or will I end up with ground noise bleeding from the non-selected channel? Any tips?
If you don't connect the non-selected channel to ground, it will hum. When you select the "clean" channel, the high-gain channel will probably buzz like a hive of angry bees.

Use a DPDT switch.
Meadows
Quote by Jackal58
I release my inner liberal every morning when I take a shit.
Quote by SK8RDUDE411
I wont be like those jerks who dedicate their beliefs to logic and reaosn.
#5
Cheers SYK. Both amp channels are actually running clean, just one a little louder than the other.
The drive comes from various dirt pedals which'll be further back in the chain...reckon the ground noise will still be noticeable enough to be a problem?
#8
Quote by forsaknazrael
It still needs to have the inactive line sent to ground. Thats where the hum will come from.

Here:
http://fulltone.com/PDfFiles/AB_switcher.pdf
Ignore the row of lugs connected to power and the LEDS.

Looks good - that's the diagram I was planning to use for the final build, if my hastily cobbled together proof-of-concept proves to be a success when tested in a band context.


I'll probably just go for a rough build using the SPDT switch and if it has the desired effect I'll retrofit a DPDT and maybe some LED indicators.

I know the SPDT circuit is very very basic but I'm not electrically-minded: how should I wire it all up?
#9
Quote by kyle62
I know the SPDT circuit is very very basic but I'm not electrically-minded: how should I wire it all up?
- 3 mono phone jacks.
- all grounds tied together.
- hot of the input phone jack goes to the pole of the switch
- hot of the A and B output jacks go to each of the throws of the switch.

Quote by kyle62
I'll probably just go for a rough build using the SPDT switch and if it has the desired effect I'll retrofit a DPDT and maybe some LED indicators.
Decide if you do or don't want LEDs. If you want LEDs, use a 3PDT switch. Else you can just use a DPDT.

Save your time and effort. Don't bother with the SPDT version. You won't be satisfied.
Meadows
Quote by Jackal58
I release my inner liberal every morning when I take a shit.
Quote by SK8RDUDE411
I wont be like those jerks who dedicate their beliefs to logic and reaosn.
#12




Managed to get it working perfectly in the end, no noise that I can tell but I'll give it a good high-gain testing at my next gig tomorrow. A bit rough but it should do the job.

Cheers for the help!