Building a Volume Pedal for FX Loop

[George]

What parts/schematic do you need to build one of these?

Amp Volume Booster thing

I'm sure it's just a volume pot in a case that you put in your FX loop. It seems straight forward enough but at what he's charging it makes me think there's some kind of mass science going on.

[Johno]

Build a boost cheap http://www.musikding.de/index.php/cat/c ... -Kits.html

[George]

I don't think that's the same thing. What I linked to is literally one volume pot in a box with ins and outs.

Either way I think I might be after an attenuator or something completely different. Need to try one out.

[rodvonbon]

This thread might be the same thing your talking about. I made it with spare parts and didn't cost me a dime.
http://www.shortscale.org/forum/viewtop ... lume+pedal

[George]

Thanks! That's just the ticket.

The way the guy goes on about the "touchy" bit between 1 and 2 where the amp kicks-in but too loud is exactly my problem. I'm hoping to bring that down to a more late-night-friendly volume level. Switch is a bonus.

When you crank the amp and lower the pedal's volume do you get any benefit of overdriving the preamp tubes?

[Haze]

I would hope/imagine so. I've thought about building an effects loop into my bassman for this purpose.

[Mike]

It's a pot in a box.

All it is is another volume control after your preamp before your power amp. The only thing it will achieve is giving you more control over a twitchy master volume, but it won't sound any different at all from any sounds you can already get with your amp.

Everyone markets these with some bollocks about power amp saturation and it's complete balderdash.

[George]

So I built the thing (without switch) it only makes things a little bit quieter. I was hoping it would go down to silent. Could there be some sort of internal wet to dry mix pot inside my amp, or is the effect really minimal?

[Haze]

try different pot values?

[George]

Tried a 100K then a 250K and didn't really hear a difference. Pretty sure I followed this schematic to the letter too...

[rodvonbon]

It's pretty much the same layout I did for mine, just without the switch. The only thing I can see that's different is I didn't solder lug 1 to the back of the pot.
If you follow the yellow and red wires in my diagram and ignore the switch, you see it's the same.

[George]

Thanks rod. Here's my shoddy embarrassing attempt...



I can confirm it definitely works, just not very well. Could it be to do with the FX loop being parallel not serial? I don't know which it is but just a thought...

[rodvonbon]

It looks like you've got the tip wire of the plug on the right jumpered to the back of the pot. Un-do that connection.

[Gabriel]

I just made that and it works perfectly, I'm just going to put it into a smaller enclosure tomorrow.

[George]

I see I've got lugs 2 and 3 mixed up. I'm gonna have a swing at this tomorrow and I'll let you know. Thanks for the help.

[rodvonbon]

I see I've got lugs 2 and 3 mixed up. I'm gonna have a swing at this tomorrow and I'll let you know. Thanks for the help.

No, your fine, just need to cut the wire going from the lug to the back of the pot. It will take you 1 second and should work after that.

[George]

Okay, cut that off and it behaves the same way. I plugged it between guitar and amp and it goes down to 0 so it does work.

I think my amp must have a parallel FX loop. Plugged in all manner of pedals that I know for a fact go down to 0/silent. All of them do the same thing.

Thanks but I think I've hit a wall on this!

[George]

F*ck it. I'm gonna try and make my amp have a serial FX loop.

If it's as simple as changing something like this...



to this...



I'll swallow it and run a mile.