Technics SU-8075(75A)
¥ 62,800 (around 1977)
Commentary
Integrated DC amplifier that achieves total DC conversion from high-level input terminal to speaker output terminal.
The DC main amplifier section consists of a first stage differential amplifier, a voltage amplifier stage, an emitter follower and a two stage Darlington connected output stage. To directly amplify the high-level input, the gain is increased to 41 dB and an effective output of 62W + 62W is obtained.
A constant voltage power supply of ± 2 power supply is used for all voltage amplification stages of the preamplifier and main amplifier to minimize transient crosstalk and self-transient distortion generated in the own channel.
Special consideration is given to gain distribution, and bare distortion is designed to be low enough.
For this reason, low distortion can be achieved simply by applying stable NF lightly.
A newly developed low-noise transistor (M47LP) is used in the equalizer amplifier to improve the characteristics.
The tone control circuit uses a newly designed volume in which the capacitor and resistor of the tone control element are disconnected from the signal system at the midpoint of the knob.
An equalizer subsonic filter is used to suppress unnecessary input due to low-frequency resonance of the pickup system.
It uses a 2-way dubbing system that connects two tape decks and allows dubbing from either direction.
Model Rating
| Type | Integrated DC amplifier |
| Main Amplifier Section | |
| Effective output (simultaneous driving of both channels) | 62W + 62W (8 ohm, 20 Hz to 20 kHz) 65W + 65W (8 ohm, 1 khz) |
| Total Harmonic Distortion Factor (1 kHz, 8 Ω) | 0.02% (at rated output) 0.0015% (at rated output of -3dB, 31W output) |
| Output Bandwidth (Both channel drive, 8 Ω) | 5 Hz to 40 kHz |
| Frequency characteristic | 20 Hz ~ 20 kHz + 0 -0.1 dB DC ~ 100 kHz + 0 -3dB |
| Signal-to-noise ratio (IHF-A) | 115dB |
| Residual noise | 100 μ V |
| Damping factor | 70 (8 Ω) |
| Input Sensitivity / Impedance | 1V/47k Ω |
| Load impedance | Main or Remote : 4 Ω ~ 16 Ω Main + Remote : 8 Ω ~ 16 Ω |
| Preamplifier Section | |
| Input Sensitivity / Impedance | Phono1, 2 : 2.5mV/27k Ω / low, 47k Ω / high Tuner, Aux, Tape deck1, 2 : 200mV/35k Ω |
| Total harmonic distortion factor | 0.01% |
| SN ratio (IHF-A, main input : direct/via tone) | Phono1, 2 : 88dB/88dB Tuner, Aux : 106dB/100dB |
| Frequency characteristic | Phono1 and 2 : RIAA standard curve ± 0.2 dB Tuner, Aux : 20 Hz to 20 kHz + 0 -0.1 dB 0.2 Hz ~ 100 kHz + 0 -3dB |
| Phono maximum allowable input (1 kHz, RMS) | 260mV |
| Rated Output / Impedance | Pre out : 1 V (rated), 8 V (maximum) Rec out1, 2 : 200 mV |
| Tone control | Bass : ± 7.5 dB (50 Hz) Treble : ± 7.5 dB (20 kHz) |
| Subsonic filter | 30 Hz, -12dB |
| High filter | 10 kHz, -6dB/oct. |
| Loudness control (Volume -30dB) | +8dB(100Hz) |
| <General> | |
| Pwer | 100 VAC, 50Hz/60Hz |
| Power consumption | 150W |
| External dimensions | Width 450x Height 140x Depth 361 mm |
| Weight | 11.2kg |