Volume control pedal

[Willybomb]

Gudday all, this might sound a bit odd, but I'm wondering how to go about building a volume pedal.

Why?  Well, I've just moved to a modelling/powered foldback setup using pedals for my sound (dirt, effects, cab sim) and using the foldback to simply amplify that.  I don't want to adjust the volume on the fly with an expression pedal (which would probably be the easiest option), I just want to bend down and turn a knob at the end of the signal chain (but before the amp) left or right and leave it set.

Any ideas for the circuit?  Doesn't have to be complex but I'd rather it didn't color the sound at all one way or the other.

Thanks, Willy.

[jimilee]

It's been a topic on numerous occasions, and deemed cheaper to buy and mod rather than build. This biggest hurdle seems to be an enclosure. If you do a search, it will come up with lots of results, but sadly no circuits.

[ThePastRecedes]

This would be your simplest solution:

[Vallhagen]

If i get you right: You just want a master of mastervolumes control?

I would box a buffer with volume. Preferably something like this: http://tagboardeffects.blogspot.se/2011/04/klon-buffer.html (my first google hit) and a log pot - say 10k - on the output.

Cheers:)

[Willybomb]

Thanks all.  I probably wasn't clear enough.  The cab has it's own volume controls, but they're on the back side where these things usually have them and are pretty inconvienent to get to.  So, I want to run the cab pretty hard and control it from the board.

ThePastRecedes - that's pretty much what I had in mind, but I wasn't sure how that would go in terms of tone or whatever.  I'd probably even forgo the switch.

Vallhagen - why the buffer?  That's to stop treble bleed from the pot, yeah?

[Vallhagen]

Vallhagen - why the buffer?  That's to stop treble bleed from the pot, yeah?

Yea. If it is a buffer you can put "any circuit" before it in the signal chain. It safely takes care of the impedance questions, if any. On the other hand; it adds components to your signal path, and noone gets happier for a "buffer after a buffer". Make a bypass option:).

Cheers

[Willybomb]

Hmm... I don't remember posting this in the projects request forum, but here it is anyway.

Ok.  The concept of this volume box is getting a bit more complex - I'm thinking it now needs a cabinet sim and XLR out as well as an unbalanced out.  (Before too long I'll probably think it needs an effects loop, chorus, reverb and an OD).

I've built the Klon buffer as suggested, I'll probably build the AMT S1 cab sim or something similar and then route all that through the volume pot and out to the XLR.

My question is:  Is it really that easy to convert from unbalanced to balanced?  One transformer?  I've modified this image to remove the speaker/line level switch that was originally there as it's just going to servicing guitar pedal output levels, whatever they are..  What would happen if this got hooked up to phantom power?  Just imagine that the buffer and speaker sim are already hooked up and switchable on the input.

After all this it might be easier to mod a volume pot into my Ultra-GI, but the jack locations give me the irrits.

[Willybomb]

Or, is adding a balanced output as easy as this:

[kothoma]

My question is:  Is it really that easy to convert from unbalanced to balanced?  One transformer? 

Yes, that's one possibility. Another is to invert the (hot) signal with an op amp (to get the cold one).

[kothoma]

Or, is adding a balanced output as easy as this:

No, connecting cold and ground is only a way to make the balanced signal unbalanced (throwing away the inverted signal), or to feed an unbalanced one to a balanced input, but you won't get the benefits of a balanced line, which is to be able to subtract out any noise/interferance added on the length of the wire at the receiving end.

[Willybomb]

So, there I am, going slightly crazy thinking about this "volume" pedal that is now morphing into what is pretty much an amp-in-a-box without a power section.  Currently it's going to go at the end of the signal chain and feature the following:

Tonemender, for overall ampish eq which the PA bin doesn't have.
Cab sim, if I can find a small vero one that works (I've built, but yet to test the AMT cab sim), switchable in/out
Klon buffer, also switchable in/out
Volume pot.  You know, for the original purpose.

I'd like to include a balanced output but it's starting to get a bit silly.  As it is, I'm going to have to try and fit 3 veros, 5 pots, and three dpdt switches into something 1590bb (preferable) or 1790ns sized (more likely).

And then I see this: http://www.mooeraudio.com/en/ProductInfo.asp?id=93
Which is sorta halfway to what I want.  The layout is better for a pedalboard than the berry GDI-21 (in on one side, both outs on the other, and it's probably 1/3 the size.  Maybe I'll just build the tonemender and put the mooer next to it.

But where's the fun in that?

[papasaurus84]

Dunno this' gonna help or not, but i've built a buffer-splitter-cabsim-master out pedal in a 1590B. It's Paul Stevenson buffer/splitter. Output 1 goes directly to pots, and the other goes to tonepad's speaker simulator, which i add an output pots after it. My goal is having two outputs, to amp and to keyboard amp or active speaker (fyi; we practice in a small rented studio that not always have a good amp, so i need to anticipate this). Actually, i have a plan to add a delay circuit before all of this board, so i can get a "finishing box" contains of delay, buffer, splitter, and cabsim. It will be done in couple weeks. .

the demo of this box (w/o delay added): http://www.youtube.com/watch?v=3hMi1CeaWSU

thats a boneyard v.1 connected to this box.

[Willybomb]

Thanks for all the input guys.  It's finished and can be found here:

http://www.madbeanpedals.com/forum/index.php?topic=17425.0

I have to admit, the buffer sounds pretty nice on it's own, but I'm not sure if that's because it's a touch above unity and "louder=better".