Gate Invert?

[abowyerlowe at mindscape.com]

Hey people,

I've got a Kenton Pro-Solo that I wish to use to Midi up my PowerTran 
Transcendent 2000 (the kit synth from ETI in the early 70's). Unfortunately, the
T2000 takes negative gate (< -3v), while the Pro-Solo only puts out positive 
gates.

Now, I'm sure this is easy to you groovy electronic hackers out there, but I'm 
just a poor software guy! I figure the solution would involve the negative input
of an op-amp, but 've never grokked op-amps, no matter how many Brabanti books I
read.

Will the circuit to invert the signal need a dual-rail power supply? I'd rather 
build something that runs off batteries, 'cos I'm wary (= scared) of building 
power supplies at this point in my electronic hacking career.

Thanks for any help,
Anthony.
--
Anthony Bowyer-Lowe. Audio Programmer @ Mindscape (UK).
                     The Essence Of Anthony @ Amudarya Studios.