Audio Database
SA-5
Commentary

A tube type preamplifier in which a DC power supply unit and a control amplifier unit are housed in a separate case.

The power supply unit containing the large-capacity power transformer, filament constant voltage circuit, rectifier circuit, and filter circuit is separated from the amplifier body and separated into a separate case. This reduces the adverse effect of AC hum noise caused by high voltage or filament voltage on the circuit of the body.

Four 6DJ8 are used for each channel for the RIAA amplifier and line amplifier. The constant voltage circuit consists of 5651 for reference voltage, 6JC6A for error amplifier, and 6CG5 for series regulator.
A constant voltage filament circuit is maintained inside the DC power supply unit to extend the life of the vacuum tube and improve its performance.

In order to obtain the optimum load of the cartridge to be used, it is possible to switch the load using a unique microjack method. This is realized by installing a microjack in the RIAA circuit and inserting a lead wire of fixed resistance. The spring inside the microjack lightly holds the lead wire. Thus, the optimum load can be selected for the cartridge to be used while easily changing the load.

The vacuum tubes of the audio stage are pre-adjusted for bias and all other adjustments before shipment, so even the same 6DJ8 is individually adjusted for bias and color.

In addition to the silver model, there was also a black model.

Model Rating
Type Tube type preamplifier
Gain (1 kHz) Low-gain RIAA input : 49 dB
High-gain RIAA input : 65 dB
Playback bandwidth 5 Hz ~ 88 kHz (No Load)
5.5 Hz ~ 83 kHz (at 50k Ω load)
5.5 Hz ~ 50 kHz (50k Ω, 1000 pF Load)
Signal-to-noise ratio (100 mv
1 kHz input standard)
-86dB (400 Hz to 80 kHz, input short)
-83dB (20 hz to 80 khz, input short)
Total harmonic distortion factor 0.18% (1 kHz at 1 Vrms output)
RIAA deviation 40 Hz to 22 kHz ± 0.05 dB
Rise time 4 μ sec (No Load)
7 μ sec (at 1000 pf Load)
Maximum power output 30 v (peak)
External dimensions Body : Width 483x Height 64x Depth 297 mm
Power Supply : 105 mm W x 110 mm H x 293 mm D
Weight Body : 4.7 kg
Power supply : 3.4 kg