TRIODE 845Signature

Commentary

A monaural power amplifier developed to draw out the bottom power of 845 vacuum tubes.

In order to maximize the capacity of the 845, a 300B power drive using 300B in the drive stage is adopted.

The power supply unit is designed with two independent systems that separate the drive stage and output stage. This reduces mutual interference and minimizes the effect of instantaneous excessive input signals on the other stages.
In addition, a toroidal core is used for the transformer to prevent noise.

The electrolytic capacitor for voltage B is equipped with a 500V/800uF Celafine large-capacity capacitor.

MITcap is used for the signal circuit to enhance the completeness.

The front panel is equipped with an ammeter that can check 845 current and can also be used for adjustment.
The plate voltage is set to 950 v for 845 and 410 v for 300B.

A power transformer for the drive stage, choke transformer, and driver transformer are arranged in the case on the right.
The case on the left has a power transformer for the power stage on the front side and an output transformer on the rear side.

It is equipped with a relay that operates when the power is turned on. The output tube is protected by turning it ON after 30 seconds.

The bias method is fixed bias for 845 and self-bias for 300B.

A 6N high purity cable is used for the internal signal line.

TAOC special order insulators are used for the legs.

High-grade power supply cable μ -PS15 of Furukawa Electric is used for the cable.

Model Rating

Type	Tube type monaural power amplifier
Maximum power output	Pure A-class 28W
Frequency characteristic	15 Hz to 30 kHz ± 1.0 dB
Total harmonic distortion factor	0.1% or Less (1 kHz)
Signal-to-noise ratio	90dB
Input Sensitivity / Impedance	1000mV/100k Ω
Output terminal	4 Ω, 8 Ω, 16 Ω
Vacuum tube used	845 300B 6SN7 6SL7
Power consumption	150W
External dimensions	Width 285x Height 210x Depth 470 mm
Weight	33kg