Audio Database


A vacuum tube power amplifier announced as the second A & M power amplifier.

KT-88 has been adopted for the output tube, and it has been designed to bring out the full power of KT-88 and aim at the latest for the present day.

The driver stage uses a cathode follower circuit using 12BH7A.
12BH7A with large plate loss supplies a strong drive voltage with low output impedance and no waveform distortion to the power tube.
In addition, it is directly connected to the power tube, and a stable drive without transient distortion is realized by eliminating the condenser.

A meter for adjusting the output tube bias current and a selector switch are mounted on the front panel.
This allows the optimum operating point of the output tube to be checked and the semi-fixed VR can be easily adjusted from the top of the chassis in case of bias deviation.

High sound quality is achieved by 1.1 point manual wiring without using a printed circuit board.

Tamura's highest-grade transformer is used for the output transformer.
With transformer technology that meets the standards of the Defense Agency, tamura Manufacturing has a high track record for broadcasting stations. The transformer adopted is a large type with input resistance of more than 100W. Moreover, the constant loss is as low as 0.25 dB. In addition, by adopting a special oriented core for the core of the transformer, there is no gap over entire band.

Parts are not only good in sound quality, but also highly reliable parts that can withstand long-term use. We select parts that can maintain initial performance regardless of the environment under which they are used.
All of the semi-fixed VRs are wound type large (30 φ) enclosed type, while the 8P socket is made of Lux, the 9P socket is made of Cinch, and the 9P first stage tube is made of tight gold plating. These are highly reliable parts.

The front input can be directly connected to the first stage tube without passing through a shield wire.
It can be used in the same way as a normal input terminal and can be played back without losing the sound quality of CDs.

By using the front attenuator, you can play without connecting a preamplifier.

Model Rating
Type Stereo power amplifier
Effective power 80W + 80W (8 Ω)
Total harmonic distortion factor 0.07% or Less (1 kHz, 1W)
1.0% or Less (1 kHz, 80W)
Frequency characteristic 20 Hz ~ 20 kHz ± 1 dB or Less (80W)
Input sensitivity 1V
Impedance 100k Ω
Signal-to-noise ratio 100 dB (IHF-A, input short)
Load impedance 4 Ω, 8 Ω
Attachment mechanism Input Selector
Bias adjustment mechanism
Vacuum tube used 12AX7A : 2
12AU7A : 2
12BH7A : 2
KT88 : 4
Power supply voltage 100 VAC, 50Hz/60Hz
Power consumption Approx. 300W (Electrical Appliance and Material Control Law)
External dimensions Width 415x Height 223x Depth 380 mm
Weight 32kg