Audio Database

The

SANSUI BA-F1
120,000yen(around the 1979 time)

Description
 
DC power amplifier which adopted the diamond differential circuit.

The diamond differential circuit is adopted as the predrive stage.
The cascode and the dual complimentary diamond differential circuit by bootstrap are used for the voltage differential-amplification circuitry with the direct couple current source and the 2nd step of predrive stage which use the Dual FET through which the first rank can send a large current by a low-noise. And on the last power stage, NM transistor of SANSUI custom is used and it constitutes from an electric-current differential push-pull circuit.
Little transmit with 2pole phase compensator and an interval distorted to a high region is realized.

The large-sized EI transformer is arranged in the center of a chassis at the power-source part.
This transformer saves the positive operation also in the time of full power by right-and-left independent 2 coil and two rectifier circuits.
Moreover, newly developed custom-made electrolytic capacitor 15,000 micro Fx4 is adopted.

In order to diffuse the exothermic from a power transistor, the heat dissipation is coped with by the chimney type large-sized heat sink and the bonnet design which employs it efficiently.

The large-sized power meter is carried.
If the peek indicator is a meter scale (PAT.PEND) which embeds peek meter between 0dB - +5dB and a peak level is detected, it carries out a lighting operation and directs the peak value of a pulse signal, the music source, etc. at a quick velocity.

In order to employ a diamond differential circuit efficiently, the symmetrical monophonic construction is adopted.
It is a block location in alignment with the fluence of the signal.
Moreover, with the Out Put change-over switch which achieved the right-and-left independency, the product line from the output transistor within amplifier to an output-terminal is shortened, and the transmit loss is suppressed to the minimum.

Right-and-left channel independent input volume.

A power switch with a large-sized indicator.

Standby AC plug socket 2 circuitry (interlocking 100W un-interlocking 200W).

Large-sized grounding terminal.

EIA specification rack-mounted adapter adjunct.

Rear
Internal
Meter
Power-source
A

Rating of a mode
Form Stereo DC power amplifier
Effective output (both ch(es) operation) 110W+110W (8 ohms, 10Hz - 20kHz, THD 0.008%)
110W+110W (8 ohms, 1kHz, THD 0.003%)
THD (10Hz - 20kHz) 0.008% or less (8ohms)
Cross modulation distortion (70Hz:7kHz=4:1) 0.008% or less (8ohms)
Output bandwidth (IHF, THD 0.02%, both ch(es) operation) 3Hz - 70kHz (8ohms)
Dumping factor (IHF, 1kHz, both channel operation) 100 (8ohms)
Frequency characteristic (1W) DC-600kHz+0 -3dB
Input sensitivity/input impedance (1kHz) 1V/25kohm
SN ratio (IHF, A network, a short circuit) 125dB or more
Channel separation (IHF) 105dB or more (1kHz)
98dB or more (10kHz)
Rise time 0.5microsec
Slew rate ±200v/microsec
Load impedance 4-16ohm
The speaker used A, B:4-16ohms
A+B: More than 8ohm
Power dissipation (Electrical Appliance and Material Control Law) 250W
Dimensions Width 430x height 187x depth of 430mm
With a rack-mounted adapter: Width 482x depth of 450mm
Weight 20kg
With a rack-mounted adapter: 20.3kg