DYNACO Stereo-70
Finished products : Released in 1958
¥ 60,500 (around 1970)
¥ 89,000 (around 1976)
Kit : ¥ 69,000 (around 1976)
Commentary
A stereo power amplifier incorporating the basic design of the famous monaural power amplifier Mark-III as it is for stereo.
The output transformer is a custom-made output transformer made by Acrosound Inc., which was established by David Hafler, the founder of DYNACO.
By using spare parts throughout the entire circuit, aging due to long-term use is reduced.
In particular, the output tube is limited to 65% of the rated output, and the filter condenser is operated at less than 85% of the rated voltage.
Model Rating
Type | Bulb type stereo power amplifier |
Rated output | 35W + 35W (20 Hz to 20 kHz) |
IHF output | 45W+45W |
Maximum power output | 80W+80W |
Frequency characteristic | 10 Hz to 40 kHz ± 0.5 dB |
Total harmonic distortion factor | 1% or Less (Rated Output) 0.05% or Less (at 1W Output) |
Cross modulation distortion factor | 1% or Less (Rated Output) 0.05% or Less (at 1W) |
Signal-to-noise ratio | 90 dB or more (at rated output) |
Damping factor | 20 |
Separation | 55 dB or More (20 Hz to 20 kHz) |
Input Sensitivity / Impedance | 1.3 V (at rated output) |
Output impedance | 4 Ω, 8 Ω, 16 Ω |
Accessory circuit | Preamp Power Sockets (2 Pairs) Dyna-bias set adjuster Monaural / stereo selector switch |
Vacuum tube used | EL-34 (6CA7) : 4 pieces 7199 : 2 pieces GZ-34 (5AR4) : 1 piece |
Power consumption | 190W |
External dimensions | Width 330x Height 165x Depth 240 mm |
Weight | 12.5kg |