I always get a lot of requests for modifying a CORNET2 or BUGLE for use as a tape head preamplifier. What are the values for NAB equalization at 15ips? Well, I finally had a moment to dig into this...
From what I can find there is a bass pole at 50Hz and a treble zero at 3.183kHz. The EQ is very similar to the RIAA of a phonostage, but with just one section. I chose to do the EQ in the first stage. Overall gain should go up a bit.
CORNET2: Set R205 = 1k and remove R213 and C204.
BUGLE: Set R10 = 14.3k and R14 = 226 ohms. R8 = 0 (jumper). Remove R13 and C2. Copy in other channel.
I have not actually tried out these values, they are based on calculations and theoretically will get you close. If anyone tries this, please comment on your results.
jh
