HELP - ADVICE NEEDED ASAP on ROLAND TDA-700 AMP

I am totally new to theremins and have an opportunity to buy a nice Roland TDA-700 amplifier. I don't even have a theremin yet BUT my new theremini is supposed to arrive tomorrow AND I am going to buy a real theremin one day next week! I know the TDA-700 is designed for the Roland V Drums but it has 3 inputs, one dedicated for V-drums, and I need to know if it will work for theremini and theremin. The guy who has it listed says it is a KEYBOARD/vocal/PA/V Drum amp and I just don't want to buy something that won't work. SHOULD I wait and buy a keyboard specific amp like a ROLAND KC500/550?? The 700 has a 15" speaker. THANKS!!!

You might try a small vocal or keyboard amp (not a guitar amp).  10" speaker or so, I don't think there is much need to go larger.  The ability to mount it on a pole up near head level behind you would be a plus.

A single active PA speaker might be another option.

Last year I got a Behringer Ultratone K450FX keyboard/PA amp.  Thierry highly recommends this one and I have to concur wholeheartedly.  Soooo much better than the little 15 watt unit that I started with.  They are around $200 new.