| Title | Value |
|---|---|
| General | General |
| Circuit : | FM-stereo / FM-AM superheterodyne tuner |
| DC quasi-complementary symmetry (SEPP OTL) amplifier | |
| Semiconductors : | 5 ICs |
| 49 transistors | |
| (4 FETs & 11 transistors for reception) | |
| (34 transistors for auxiliary circuit) | |
| 29 diodes | |
| Dimensions : | 47,1 x 15,7 x 37,5cm |
| Weight : | 15,3kg. |
| PRE/MAIN section | PRE/MAIN section |
| Dynamic power output : | 200W (4 Ohm, IHF constant ps method) |
| 136W (8 Ohm, IHF constant ps method) | |
| Continuous power output : | 2x 45W (8 Ohm, 1Khz, 0,2% THD) |
| 2x 55W (4 Ohm, 1Khz, 0,2% THD) | |
| 2x 35W (8 Ohm, 20Hz...20Khz, 0,2% THD) | |
| 2x 45W (8 Ohm, DIN 45500, 0,2% THD) | |
| Power bandwidth : | 15Hz...35Khz |
| THD : | < 0,2% (rated output) |
| < 0,1% (1W output) | |
| < 0,2% (rated output, 20Hz...20Khz) | |
| IMD : | < 0,2% (rated output) |
| < 0,1% (1W output) | |
| Frequency response : | ± 1dB (RIAA) |
| 10Hz...70Khz (lines, +0 / -3dB) | |
| 10Hz...100Khz (main amp, 1W output, +0 / -3dB) | |
| Inputs : | 2mV / 47kOhm (phono) |
| 150mV / 50kOhm (lines) | |
| Outputs : | 250mV / 10kOhm (RCA rec out) |
| 1V / 4,7kOhm (pre out) | |
| 30mV / 82kOhm (DIN rec out) | |
| 8 Ohm...10kOhm (headphones load) | |
| S/N ratio : | 70dB (phono, 3mV input) |
| 90dB (lines, 250mV input) | |
| 100dB (main amp, 1V input) | |
| Damping factor : | > 50 at 8 Ohm |
| Bass control : | ± 10dB at 100Hz |
| Treble control : | ± 10dB at 10Khz |
| High filter : | 12dB/octave above 9Khz |
| Low filter : | 12dB/octave below 50Hz |
| Loudness control : | +10dB at 50Hz / +4dB at 10Khz |
| FM section | FM section |
| Intermediate frequency : | 10,7MHz |
| Sensitivity : | 2,0µV (IHF) |
| 1,6µV (S/N ratio = 30dB) | |
| Image rejection : | 70dB |
| IF rejection : | 100dB |
| Spurious rejection : | 90dB |
| AM suppression : | 56dB |
| Capture ratio : | 1,0dB |
| Selectivity : | 70dB (IHF) |
| S/N ratio : | 70dB |
| Frequency response : | 20Hz...15Khz (± 1dB) |
| THD : | 0,2% (400Hz, mono, 100% modulation) |
| 0,5% (400Hz, stereo, 100% modulation) | |
| Stereo separation : | > 38dB at 400Hz |
| Carrier suppression : | 40dB |
| AM section | AM section |
| Intermediate frequency : | 455Khz |
| Sensitivity : | 53dB/m (built-in antenna, 1MHz) |
| 30µV (external antenna) | |
| Image rejection : | 50dB at 1MHz |
| IF rejection : | 40dB at 1MHz |
| S/N ratio : | 50dB at 50mV/m |
| THD : | 0,8% at 50mV/m |
Sony STR-7055
1972
1976
The 1970s near-equivalent to the 1960s STR-6120 and STR-6200F - same lineup near-topper status, same quality but a very different internal structure and componentry.
Gone was the lavish simplicity and cleanlisness of the cabling and PCB placing of the late 1960s ES units - in came the more... hectic connection between boards and stages : lots of inputs and outputs but lots of (very) hectic cabling, too.
Sony made up for this with the incredibly fine-tuned and classy design of the front.
The differences between the 7055 and the real topper STR-7065 lie in more power, a third output for an extra loudspeaker pair, the possibility to mix two microphones together (where the AUX input is on the 7055) and a supplementary meter to show FM input signal.
The rest is the same : DC structure (yes), FET-charged 4-gang varicap, all the possible connections, a big trafo powering everybody, large heatsinks protruding through the back, two pairs of Sony PNP / NPN power transistors, three pairs of loudspeakers' outputs and a separable pre/main loop.
At 3295FF (french Francs) in 1973, this was the high-fidelity of the fairly rich and this still shows today - in spades. Despite often higher list prices, Sony sold a lot and a lot of STR-7055.
Replaced by the very rare ES-II-like STR-7800SD and its more common STR-6800SD brother.
page online since : october 2008
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page type : LGT / KNB
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page updated : not yet
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