Can I add a boost to one channel of an AB splitter

[PSM1968]

Hi, I've got limited electronics knowledge but can work a soldering iron.

I've got an AB splitter (Belcat ABS-520) with separate volume controls for each channel.

The output from one of my guitars is a lot lower than the other one and I want to add a bit of boost to it, save me walking over to the amp or buying another boost pedal.

I've opened up the box and it looks fairly simple, with 2 250 pots and a couple of resisters early on the circuit which I am assuming are related to the LED.

I want to add a boost circuit to this like the ones I've seen on here.

My basic ignorance of electronics is telling me I should be able to just solder the boost circuit inline, substituting the input/output/volume/etc from the boost circuit with that in the AB box?

Question is - is it possible? Will I need to change any of the parts in the AB box, such as a pot?

If this isn't the way to do it, is there a way?

All help massively appreciated.

Cheers,

Paul

[ashcat_lt]

The easiest way is probably to put a resistor in series before the switch and then use another switch to short it when you plug in the quieter guitar.  It's kind of the opposite of a boost, but if you turn up the amp a little, it'll work out the same.  Otherwise, yeah, just stick your favorite booster in front of the A/B, between the In jack and the switch.

[Ben N]

A garden variety dual opamp can give you buffer + boost, which will be very clean, especially if you can feed it more than 9v, and will give a nice low-Z output on both sides. If you would like a simplified project, have a look at the AMZ dual opamp board

[ashcat_lt]

Wait, you said splitter!  Which way are you running this thing?  Is it splitting one input to two amps, or selecting between two inputs going to one amp?  If you're actually using it to switch between the guitars, then why not just use the V pots that are on the thing?

It doesn't actually require two opamps.  You could build  a single opamp gain stage, and use a switch to change the total gain.  I actually built one a few years ago for my then bandmate so he could keep his guitar and mandolin plugged in, and when he switched to the mandolin there'd be a boost to account for its lower output.  In that case one pole of the stomp switch just shorted across the opamp's feedback path, making it into a unity gain buffer.

[PSM1968]

Just noticed I've posted two threads - doh!! 

Anyhow, it inputs 2 guitars to one output to my amp.

I bought this particular splitter because it did have the volume pots, but its still not enough, even if they are at the 2 extremes.

Is it possible to do something simple with one of the pots to add a bit of boost to one channel?

I don't really understand what you're talking about building a single opamp stage?

[ashcat_lt]

You can't have actual boost without active electronics.  An opamp gain stage is one of the simplest possible ways to get that, but if you don't know what that means...

Do the V pots not go all the way to silence?  Can you maybe trace out the existing wiring or at least take some good, focused pictures of the guts?

[PSM1968]

Finally worked out how to post pictures.

Here are some of the guts of the AB box.

Overhead, from the front and the back.

2 of the underside of the board - from front & back again

And 1 kind of long view from the power in end.

https://www.dropbox.com/s/jnzzjmio4onit7a/Overhead1.JPG?dl=0

https://www.dropbox.com/s/pazavsug80vgyzs/Overhead2.JPG?dl=0

https://www.dropbox.com/s/yam3kswq3i8xh26/Underside1.JPG?dl=0

https://www.dropbox.com/s/m8wfq6o81hoi9kl/Underside2.JPG?dl=0

https://www.dropbox.com/s/hrtph5240efxwlb/Power%20in%20end.JPG?dl=0

Hope that all makes sense.

P