Tube stereo power amplifier.
The Electronic Industries ST-70 C2 was the second amplifier on the Dynaco ST-70 modification series. It was manufactured by Electronic Industries at 2451 Hennepin Avenue S in Minneapolis, Minnesota. The Electronic Industries ST-70 C2 took the original Electronic Industries ST-70 C1 and made improvements which resulted in better performance. Some of the improvements included:
The amplifier came from the factory with high quality Mullard EL-34 output tubes and Telefunken and RCA input tubes. These amplifiers were produced in very limited quantities; more than likely less than 100 amplifiers were produced. The amplifier was available direct from the factory; no kits were sold to the public. Historically, this was the first revision that was ever offered to the public for an Electronic Industries product. An owner of the Electronic Industries C1 amplifier could have their amplifier upgraded to the C2 status for a marginal fee. William Z Johnson built or upgraded most of the Electronic Industries ST-70 C2 amplifiers himself.
MSRP (US new retail)
|Overall negative feedback|
|Hum & noise|
|Power supply energy storage|
|Tube complement||(2) OA2, (2) ECC-83, (4) 6FQ7 or 6CG7, (4) EL-34, (1) 5AR4 or GZ34|