Two Pedals - One Box - Master Volume - asking the impossible?

[poodlebra]

I've put together a twin version of a 'Great Destroyer', utilising both sides of the chip. it's effectively two pedals in one box, each TGD having it's own 3pdt footswitch wired as true bypass with grounded input (as detailed at GGG).

what i wanted to do, which sounded so simple in my head, was add an overall master volume to this monstrous device, as each TGD churns out a mammoth amount of signal, and the volume control on each one really makes a difference to the oscillation, not just volume.

however, now i'm sitting with a drilled box, circuit, many pots and a hot soldering iron, i've just realised i have no idea how to do this. any ideas?

i did think a dual gang 500k, one on each of the outputs, would do it, but that's a bit of a compromise, as it'll effect how much goes into circuit two from circuit one, again altering the overall sound.

any ideas greatly appreciated, or do i just resign myself to grommeting the hole i drilled for master volume?



(input 2 goes to left of cap - should fix this on diagram!)

[Joe Hart]

Wouldn't you just wire up a pot like a volume pedal (shunting the signal to ground)?
-Joe Hart

[Thomeeque]

Do you have 3DPT footswitches? - sorry, you do, now I see it..

Do you have link to 'Great Destroyer' schema (or at least pot values)?

Just to be clear, you want master volume control at the very output effective when at least one of TGD's is engaged, right?

T.

[poodlebra]

joe - yes, in theory, but where without affecting the bypassed signal?

thomeeque - yes, that's exactly it. master volume when one, other, or both are engaged.

here's the schematic (using only one side of the chip - i added second circuit on right - they share a starve control).



thanks for your help

[_dB]

I might be thinking about this wrong, but here's what I figure:

You can't do a master volume AND keep everything true bypass unless you change your switch wiring. (If you just add a volume pot to the output of the second stage and that stage gets bypassed, you lose your master vol)

Now you have 2 options (at least):

Add a 3rd switch (BYPASS) which bypasses the whole chain. Then the other 2 switches (TGD 1 and TGD 2) to control each side. Now you can have a volume pot or what have you at the after the second stage, but still in the effect circuit when the main BYPASS switch is on.

OR

If you are willing to give up individual control of each side, wire it up so that Switch 1 is BYPASS for the whole circuit and Switch 2 is ENGAGE SIDE 2.  This way you can either have nothing, 1 side, or both sides together. Does it matter a lot to be able to engage each side separately, since they are essentially the same circuit? Might not be such a big sacrifice..

dB

[poodlebra]

sorry, i forgot to mention that i changed the input and output caps on the second circuit, so essentially left is guitar, right is bass. the bass caps do make the cuircuit do crazy things and sound completely different to the left circuit, so it would be good to have the left / right / both / none options if possible.

i would have just added another footswitch as you suggested, but i've got the whole thing drilled now, and don't have much use for an 8-pot box other than this!

[poodlebra]

would my idea of a dual-gang 500k wired at out 1 and out 2 work? even though it would change the volume being fed into in 2?

[knealebrown]

You have just brought this to my attention, never saw this pedal before. Its awesome!!! 
I dont usually dig fuzz much but this blows my mind. Is there a single layout anywhere?

[poodlebra]

there's a thread at freestompboxes.org with several variations of vero layout. not made one myself, as i went straight in there with my dual version (which does work well - there are links to video on that thread).

[poodlebra]

hmm. it ...'d my reply. that should have been FSB.org of course

[slacker]

would my idea of a dual-gang 500k wired at out 1 and out 2 work? even though it would change the volume being fed into in 2?

That would work, if you want to keep it as two separate pedals in one box and be true bypass I think that's the only solution.
When you want to be able to control the volumes separately, you can just turn the master up full and use the original volume controls.

[poodlebra]

next question...

how do you ascertain what value pot you need for the master volume? i only said 500k as that's what someone over at FSB suggested for the original great destroyer. it's just i know i have a couple of 250k DG pots i took out of something, but no 500k.

besides which, i live to learn  and would like to know how to work it out.

[Thomeeque]

 Do you feed it by battery or by PSU only?

Would you mind to use relay (allows true-bypass, but would suck battery quickly)?

Or would you mind output buffer (battery possible, but no true-bypass)?

T.

[poodlebra]

it has provision for battery or psu. i'd probably use psu.

i'd prefer true bypass as it is a noisy beast.

[Thomeeque]

 Well, then wire DPDT relay to form global true-bypass and control it e.g. like this:



Then you can do "inside" whatever you want.

Small signal relay actually does not need so much current (like 10-15mA) and it will use it only when FX is engaged (if you'll wire it that way ), so it could run from battery probably (some people don't mind to spend much more current on crazy status LEDs, so.. ).

T.

[poodlebra]

i'm a little lost with that, but i am slightly hung over... i'll have a good look when my head is less fuzzy.

thanks!

[Thomeeque]

i'm a little lost with that, but i am slightly hung over...

Actually I am slightly hung over too , but it should work T.

[Joe Hart]

joe - yes, in theory, but where without affecting the bypassed signal?

Sorry. I thought you wanted "A" or "A and B." But now reading the posts since my post, I see you want "A" or "B" or "A and B." In that case, you would need something else as already discussed.

How often would you use it? You could mount a third 3PDT on the side of the box or something (like the switch on the side of a Roto Vibe, or on the side of the Slash Wah -- but an actual 3PDT). If you just kind of "leave it on," then the inconvenient switch placement wouldn't be too much of an issue. Although, I would guess that you wouldn't use this pedal all the time.
-Joe Hart

[poodlebra]

to be  honest it'll probably live in a box. it's more the fact i suddenly came up against something i thought was simple, and i hate not finding solutions