Blue Shadow
Waiting for Vintage Gear from this century
The L-07M is an earlier amp than the High Speed discussion that Kenwood used throughout their line with specs for rise time and slew rate. These specs usually included a very high frequency limit for the amp. The Mk II shows this with the 600kHz top frequency. The non-Mk II doesn't go that high and is rated to 50kHz. I don't know about hard to find parts for this amp. Maybe those that have experience inside can fill in that info. I don't think using a good quality replacement transistor would change the characteristics as much as on the later Mk II amps.