Technics SU-8055 (1979–1980)
A stereo integrated DC amplifier from Technics, produced around 1979–1980, notable for its capacitor-free signal path design.
Overview
The Technics SU-8055 is a stereo integrated DC amplifier made by Technics during the late 1970s to early 1980s. It was designed to improve waveform fidelity by eliminating coupling capacitors in both the signal path and the negative feedback loop. This approach aimed to deliver cleaner audio transmission across the full frequency range. The unit features an independent recording and playback selector system, allowing separate control of input and record sources. It also includes an FL peak power meter that visually displays output levels from 0.1W to 100W in a bar graph format.
Specifications
| Product type | Stereo Integrated DC Amplifier |
| Manufacturer | Technics |
| Production years | 1979–1980 |
| Original price | ¥51,800 (approx. 650 DM) |
| Frequency response | 20Hz to 20kHz |
| Output bandwidth | 5 Hz to 30 kHz (-3dB) |
| Speaker load impedance | 4Ω |
| Total harmonic distortion | 0.03% |
| Signal-to-noise ratio | Phono: 82dB, Tuner/Aux/Tape: 97dB, Mic: 70dB |
| Phono maximum allowable input | 150mV |
| Tone control | Bass: ±10 dB (50 Hz), Treble: ±10 dB (20 kHz) |
| Subsonic filter | 30 Hz, -6dB/oct |
| Power requirement | 100 VAC, 50Hz/60Hz |
| Power consumption | 100W |
| Dimensions | 430 x 142 x 255 mm (WxHxD) |
| Weight | 7.2kg |
Design
The SU-8055 uses a DC-coupled design that removes coupling capacitors from both the signal path and the negative feedback circuit, enhancing waveform fidelity. It incorporates a single-package dual transistor in the first stage of the power amplifier, operated with a current mirror load for low-distortion performance. The output stage employs Power Pack ICs based on a two-stage Darlington connection with a pure complementary symmetry circuit. A newly developed recording and playback selector allows independent operation of record and input selection.
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