Output sharing - Volume control question.

[spacefuzz74]

I building up a little noise pedal that contains a simple fuzz and a noise oscillator in the same box.  i am not wiring them in parallel, i just want both in the same box and have switches so one or the other (or both) can be on.

neither effect will be controlling the other.

each effect has it's own volume control, but i only want one output for both effects.

problem is, the volume for the fuzz slightly impacts the oscillator volume (as well as the fuzz volume) and the volume for the oscillator slightly impacts the fuzz volume (as well as the oscillator volume).

what am i overlooking here?

thanks for any help!

[induction]

It's pretty hard to say what's going on without a circuit diagram. Got one?

Also, is your 'noise oscillator' an effect (ie. has an input and output) or a signal generator (has an output but no input), or maybe some kind of hybrid?

[spacefuzz74]

thanks for the reply.

the oscillator just has an output, no input (signal generator).

the fuzz is just a simple bass fuzz.  this one:

[induction]

Can you show us a diagram of the whole thing, or at least the bypass wiring? If the circuits are interacting, we need to know how they are connected to each other.

[spacefuzz74]

yeah - i'm not doing anything special or out of the ordinary (i don't think), i have the output from the 3pdt fuzz switch to the output jack, and lug 2 from the volume pot of the oscillator to the same output jack.  all grounded to the output jack also.   should i be using a stereo output instead of mono?

here is a photo:

[Travis]

The way you have it wired means that both volume controls will affect eachother because they will dump eachothers signals to ground depending on how they are adjusted.

You need a buffered mixer to mix the signals together without the volume controls interacting

[Muadzin]

Travis wrote

The way you have it wired means that both volume controls will affect eachother because they will dump eachothers signals to ground depending on how they are adjusted.

You need a buffered mixer to mix the signals together without the volume controls interacting

That's the first thing that came to my head when I read the OP.

Couldn't he use a SPDT on/on switch where the output of each circuit goes to the two outer lugs, with the center lug to the output plug? And thus switch safely? In which case he could also use a DPDT on/on switch and use LED's, or a bi-colored LED so he knows which board is currently connected to the output.

[induction]

Nebula 71 wrote

i have the output from the 3pdt fuzz switch to the output jack, and lug 2 from the volume pot of the oscillator to the same output jack.  

Contrary to your original post, this means they are wired in parallel.

Muadzin wrote

Couldn't he use a SPDT on/on switch where the output of each circuit goes to the two outer lugs, with the center lug to the output plug? And thus switch safely? In which case he could also use a DPDT on/on switch and use LED's, or a bi-colored LED so he knows which board is currently connected to the output.

He could, but he'd need two switch-flips to change from fuzz to oscillator, and he wouldn't be able to use them both at the same time, which he said he wants to do.

Nebula, maybe you could tell us how you plan to use this thing, and why you want them in the same box. That might make it easier for us to come up with wiring suggestions.

For example, do you want to be able to fuzz the oscillator signal? Do you want to be able to mix oscillator and fuzzed guitar together? What about oscillator and non-fuzzed guitar?

One suggestion would be to put them in series, oscillator first, so that activating the oscillator either bypasses the input signal or runs it in parallel. That means that the oscillator gets fuzzed as well as the guitar. Alternately, you could run them in parallel and use one switch to engage/bypass the whole unit, and another switch to select oscillator or fuzz, which means that the oscillator never gets fuzzed. Or you could the circuits in parallel with independent bypass switches, like you have them now, and add a mixer stage to the output like Travis suggested to avoid volume knob interaction. This would mean they can both be used simultaneously, but the oscillator never gets fuzzed. There are lots of other options, but the best approach depends entirely on how you plan to use it.

[spacefuzz74]

induction wrote

Or you could the circuits in parallel with independent bypass switches, like you have them now, and add a mixer stage to the output like Travis suggested to avoid volume knob interaction. This would mean they can both be used simultaneously, but the oscillator never gets fuzzed. There are lots of other options, but the best approach depends entirely on how you plan to use it.

this is ultimately what i want...2 separate effects in the same box that don't interact with each other, and can be used individually, or together...however, share the same output (so i don't have to have 2 output jacks).

it sounds like adding the mixer is the only way this will happen, so i'm going to try that!

thank you all for all the help and advice.

[Travis]

I have an unrelated question..

What type of enclosure is that in your pic? Looks interesting

[spacefuzz74]

hey travis - i have a pal that works in a machine shop, and he had some aluminum scrap he was able to use to make some boxes for me.

thanks again for the help!