Tube stereo power amplifier.
The amplifier used a stock Dynaco ST-70 chassis and transformers and substantially improved upon the original Dynaco ST-70 design. Some of the improvement over the stock Dynaco ST-70 included:
The ST-70 C1 did not have any labels to identify the unit that was added later on the Electronic Industries ST-70 C2.
The Electronic Industries ST-70 C1 is extremely rare with less than 50 units produced. All the units were offered factory direct, no kits were available to the public. William Z Johnson built most of the Electronic Industries ST-70 C1 amplifiers himself. The amplifiers were produced at the original Electronic Industries store/factory which was located at 2451 Hennepin Avenue S in Minneapolis, Minnesota.
MSRP (US new retail)
|Overall negative feedback|
|Hum & noise|
|Power supply energy storage|
|Tube complement||(2) OA2, (2) ECC-83, (4) 6FQ7, (4) EL-34, (1) GZ-34/SAR5|