HELP! Y-splitter pedal issue. Have I wired the 3pdt switches correctly? PIC

[big bustle]

Here's a wiring diagram of how i built the circuit. the 2 jacks in line are read as A and B from left to right. Problem Description below image...




the pedal works fine when i use the side jack as input to split to an A and B source.

the issue is when i use the A and B jacks to send to the side out put. the B side  also controls the A side. when i pull out the 1/4" input to the B side the A side works fine.

i can not for the life of me figure out why this is doing this. it seams so simple. as the single jack is multed to both switches.

my only thought is these cliff 3pdt jacks i got from small bear are supposed to be wired differently than i thought.

any help is appreciated.

thanks!

[Meanderthal]

 First, it looks like you have the switches oriented sideways(or maybe you just drew them that way). Easy to make that mistake with 3pdt. Second, hooking the grounds to the switches dosen't make sense.

I'm also pretty confused about the problem... but I can see why you're having problems(I think)

Obviously this isn't intended as a common garden variety A B box(I don't think) because of the 2 seperate switches...

Could you describe what exactly you intend to use this switcher box for?(I'm not quite sure) Just seperate on/off for a and b?

[big bustle]

thanks for responding

1) the drawing of the switches is not precise. the posts run horizontally on the 3pdt, not vertically as drawn. 

2). i thought connecting the A/B jack's grounds to the switch allowed me to have more noise/hum protection. now that i think about it the case itself is ground.  i presume i'm just creating a ground loop (albeit a tiny one). where should i connect them instead?

3) one of the purposes of the box is to take the input and split to A/B. Each A/B out put has it's own on/off switch.

that function works perfectly. including the LEDs.

where the problem lies is the pedal does not work in reverse.

as in... 2 sound sources to one amp.

when B has a 1/4' plug installed; the A channel will be muted by the B switch.

what a conundrum!


thanks again

[Meanderthal]

 Oh, I get it now... you also want to use it as a primitive mixer. (and yep, you just drew them sideways, you have'em oriented properly)

Umm... yeah, it'll work as drawn. there's no real harm switching the grounds too, but you could have just used 2 dpdt switches and wired all the grounds to each other. It's a belt and suspenders, but your pants won't fall down, that's for sure.  I wouldn't worry much about a ground loop, not a big problem for something like this.

Ok, lemme download the pic and shrink it so I can see the whole thing at once... I'll stare at it a while, maybe I'll see something I'm not noticing right now, because I'm stumped too... I'll get back to ya in a few...

[Meanderthal]

 Failure... I can't see it... it should work. (besides maybe impedance problems with the mixing, but the switching should work either way)

Would it be possible to post a gut shot?

[big bustle]

I resized the original picture. 

and here's a pic of the interior.


so...

impedance: is the impedance affected when using it to split a guitar to A/b? if so, how so?

is the impedance affected when mixing A/B to go to the single output?

i must say that considering impedance was never on my mind. i feel a bit careless now. 

hope i'm not being too aggressive with my questions. this is my second build and the more I learn the more I realize how little i actually know.

[Meanderthal]

 'k, I'm not seeing a problem in the guts either(it's late, I'm tired, etc...) but I'll have another go at it after I sleep...

About the impedance, I was referring to mixing with a simple y. I've tried that many times in the past when I was in a fix for an extra channel... and never had good results. Not even just stereo to mono. It seems one side always overpowers the other, or you get unexpected distortion, weird phase cancellation, something always gave me trouble every time I tried that. Splitting for me has never been THAT much of a problem(maybe a weak or noisy signal, but that's it), but combining can be frustrating.

I've seen schematics for simple passive mixers with no pots, just resistors, nothing more. They are said to sound pretty good for the audiophile guys, but maybe a guitar signal would have too much loss compared to line level for this to be practical.

I gotta get to bed. I'm babbling. I apologise for being no help at all... I'll give it another shot in the morning.

[mattpocket]

I am only on my second build too, but I did a fair bit of research working on a fx loop selector where the lines would be mixed to one output, if there is more than one signal, i.e your A and B jack going to the output jack then the two signals phase each other out. I am not entirely sure how to combat this, but I suggest you take a look at R.G. Keen's simple mixer over at GGG. He has 4 pots and 4 resistors, with four inputs into one output. Take a look at the circuit it would be easy to alter the circuit for your needs, even for noobs like me and you. My only concern for this then would be, would it still work the other way around, i.e. one guitar into two amps.

hope that helps

[lvs]

where the problem lies is the pedal does not work in reverse

Here's some more  information about that problem : http://www.rane.com/note109.html

[Meanderthal]

 I still can't figure out the switching problem... but that link to the Rane info has some great info, including passive mixer schematics that look appropriate for guitar signals!

[big bustle]

OH SNAP!

where the problem lies is the pedal does not work in reverse

Here's some more  information about that problem : http://www.rane.com/note109.html

this makes a lot more sense now. the two inpits i was using was a casio keyboard and a squire p-bass.
clearly the casio is going to have much different impedance than the p-bass.  i plugged in a gtr to the other end and it passed audio as a mixer.

there was a difference in the sound when both were plugged in. seemed like the low end had changed a bit if not just a small drop in overall volume.

now if only someone could explain to me why the resistors were needed in the mixer circuit. i pulled out my "getting started in electronics" book hoping for some sort of explanation.but i got nuttin'

[Meanderthal]

 The resistors prevent the impedance of the devices from loading down each others' output. Keeps the signal 'flowing' to the output, not back up the other side...

[big bustle]

The resistors prevent the impedance of the devices from loading down each others' output. Keeps the signal 'flowing' to the output, not back up the other side...

makes sense.

many thanks for your time an knowledge