I recently discovered a very cool external pick-up that works great with my 24 string psaltery. Haven't tried it on my little one but may get a pickup for that as well. http://cgi.ebay.com/JJBELECTRONICS-EXT-100-External-Acoustic-Guitar... It's on ebay for about $20 including shipping. It sticks onto to the back of your psaltery (or other instrument) with removable DAP type adhesive which is included, but I found that didn't hold very well. I prefer earthquake wax which is also easily removed but holds better. You can buy that on ebay too. You will need a small amplifier to make this work and those can usually be found reasonably at pawn shops. However sound isn't equal on every make of amp. I have a Roland micro-cube I bought on ebay and I LOVE it. Really great sound and very portable. Runs on batteries or has an optional AC/DC converter to plug it into the wall. I found a like new Microcube that came with that converter. I use the same amp for my baritone that has the amp jack built into that psaltery.
The sound from this little pick up is amazing with the right amp.
P.S. You'll also need a guitar amp cord to go between the pickup and the amp. Best to determine the length you need before getting one of those. Available at any music store or online.
P.S. I should mention that I use a good tripod and tripod mount and mount the bracket for the amp jack end of the
external pickup onto the upper part of my tripod. Great product but best used when you have the tripod mount and tripod.