Audio Database

A tube type monaural power amplifier developed by Dynaco.

The output transformer differs according to the manufacturing period, and A-431, Z-216, ZT0195, etc. are adopted depending on the age.
"Interview with David Hafler(2000)According to an overseas article, when Mark-III was released, Acrosound was not available due to patent issues, and it was used by a transformer manufacturer called TRESCO, which was close to Dinako (thank you for pointing out).
In the 1976 Herman-era catalog photograph, ZT0195 was used, and the catalog described it as an output transformer developed by Acrosound. I didn't know who produced this ZT0195, so I was not sure if it was manufactured by Acrosound or only developed (or designed by David Hafler, the founder of Dynaco and Acrosound).
* Please let me know if you know the detailed information such as manufacturing, development, development only, developed by Mr. Hafler, etc.

6550 (KT-88) is adopted for the output tube, and high power is obtained by the push-pull system.

Model Rating
Type Tube type monaural power amplifier
Output 60W (Rated)
140W (peak)
Total harmonic distortion factor 0.5% or Less (60W, 20 Hz ~ 20 kHz)
Cross modulation distortion factor 1% or Less (Rated Output)
0.5% or less (at 50W output)
0.05% or Less (at 1W Output)
Frequency characteristic 6 Hz to 60 kHz ± 0.5 dB
16 Hz ~ 25 kHz ± 0.5 dB (Maximum Output)
Input sensitivity 1.6V(60W)
Signal-to-noise ratio 90 dB or more (at rated output)
Output impedance 4 Ω, 8 Ω, 16 Ω
Damping factor 15
Vacuum tube used 6550 (KT-88) : 2 pieces
6AN8 : 1 Piece
GZ-34 (5AR4) : 1 piece
Power consumption 150W
External dimensions Width 229x Height 190x Depth 229 mm
Weight 13.5 kg (according to 1973 catalog)
12.5 kg (according to 1974 catalog)
11.5 kg (according to 1976 catalog)