Beautiful Counterpoint SA-12 Dual Channel Tube Mosfet Power Amplifier & Manual and Box
Below is from audio-database.com:
A vacuum pipe and the stereo power amplifier of the hybrid concept which adopted MOSFET.
The vacuum pipe is adopted as the drivers of all the voltage magnification stages and output stages.
Coupling of the front end constituted from this vacuum pipe is carried out to the output stage by low impedance / Hi-Current MOS FET, and the power response of MOS FET has been obtained, having a sound peculiar to vacuum-pipe amplifier by this.
Since the counter point does not accept the improvement in the characteristic by NFB as a musical thing, the output stage does not constitute the NFB loop.
While having non NFB circuit composition, the capability of SA-12 is polished by adopting the thorough ground processing and the current supply circuit designed carefully.
For a reason when a direct-current portion flows when a power source is switched on, or some very thing of an outbreak happens to AC power supply, the automatic muting mechanism is carried and the speaker is protected.
The reliability of amplifier is considered as an important factor, it is designed, and parts especially with high reliability including the German roederstein metal film air register have realized all the circuits.
Thereby, the quality of not only the physical characteristic but the music reappearance [ itself ] is improved.
There was also a silver type in addition to a black type.
Form: Hybrid stereo power amplifier
Effective output: 140W (4ohms)
Input impedance: 47kohm (100pF o'clock)
THD 1% or less (at the time of 80 ohms and an effective output)
Frequency response: 5Hz - 100kHz
Signal to noise ratio: 92dB or more
Dumping factor: 8.9 (8 ohms, 1kHz)
Valves employed: 8 (Futami pole pipe)x4 6DJ
Power consumption: 60W
Dimensions: Width 480x height 113x depth of 322mm