[GraemeJ]

Just for the sake of curiosity: What instruments and what mixer?

I play a regular electric guitar (usually Strat or Tele, depending on gig) plus a nylon strung amplified acoustic and a pedal steel guitar, often all on the one gig - I work with a couple of pretty eclectic outfits - so balancing all three is rather necessary.

The mixer is a BST Tiny 20, like this one - http://www.okazii.ro/sisteme-audio/altel...-a52190329 - which I've had for years and is probably no longer manufactured, so possibly hard to find now. I guess one might turn upon eBay, etc., so worth checking out that possibility. It has one mic/phono input channel and three mic/line channels, which is perfect for my use.

Although mixers are generally used for microphones, most will accept a line level input as well, so you should be able to find something suitable.  

The main problem is matching the input impedace of the mixer to a guitar.  Guitars should (ideally) run into a high impedance input, 1 Mohm+, whereas many mixers only offer a much lower input impedance on their line inputs.  To overcome this, you could use DI boxes, but this does mean a slightly more complex wiring and setting up time.  Mis-matching the impedances could result in a loss of high frequencies, but it's always worth trying the simple setup first and see how it performs.  I don't need DI's on this rig, so I was lucky.