Yamaha C-1

1 9 7 5 1975
1 9 8 3 1983

Alongwith the Rotel RC-5000, the C-1 probably remains as the busiest front plate of all time and the antithesis of the "straight wire with gain".

But it seems the C-1 wasn't the antithesis of neutral & natural sound -Yamaha oblige- as, like the B-1 V-FET masterpiece, the C-1 is one of the few preamplifiers that became an instant landmark in audio design.

Inside
All-FET, with small-signal V-Fets in some of its stages, constant-current / constant-load / current-mirror / fully-stabilized ±100V / ±33V EQ section, metal film, styrol and mylar caps, separate amp for headphones and a 4-gang volume control.

Front
Variable loudness, acoustic & presence tone shaping plus regular bass/treble with 2-position center/turnover frequencies for all, 4-frequency tone generator plus pink noise position, front pre-out and tape i/o, MIC inputs, 6-position phono impedance trims for inputs 1 & 2 (separately !), pre-out or rec-out meters switch with attenuator - and then some.

Back
Three phono inputs, three tape loops, three line inputs, input level trim pots for all, three pre-outputs, one input to use the meters with an external source, one oscillator output with level pot,

400,000¥ brought a lot in 1975.


Very briefly c. 1978 available in select markets in silver ; available in Japan as late as 1983.
Would be very good-looking if silver and in a custom wood enclosure !

Yamaha C-1, image 1 Yamaha C-1, image 2 Yamaha C-1, image 3
Yamaha C-1 specifications
Title Value
Inputs : 2mV...8mV / 30 - 41 - 47 - 53 - 59 - 100kOhm (phono 1 & 2)
3mV...8mV / 47kOhm (phono 3)
150mV / 50kOhm (lines & tape, variable)
2mV / 50kOhm (MIC)
775mV / 110kOhm (external meters)
Maximum input levels : 25mV...100mV (20Hz, phono 1>3)
200mV...800mV (1Khz, phono 1>3)
800mV...3200mV (10Khz, phono 1>3)
12V (lines & tape ; at 150mV setting)
200mV (MIC)
Outputs : 775mV / 300 Ohm (pre out 1 & 2)
150mV / 1kOhm (rec out 1 > 3)
50mW / 47 Ohm (headphones, for 8 Ohm load)
Maximum output levels : 775mV / 180 Ohm (oscillator output)
7,75V (pre out 1 & 2)
12V (rec out 1 > 3)
Frequency response : 30Hz...15Khz (± 0,2dB, RIAA)
5Hz...100Khz (+0 / -1,5dB, lines & tape)
20Hz...20Khz (± 0,5dB, MIC)
S/N ratio : 70dB (phono 1 > 3)
90dB (lines & tape)
60dB (MIC)
Residual noise : 0,019µW (8 Ohm headphones)
7,75µV (volume minimum)
15,5µV (volume -30dB)
THD : 0,02% (20Hz...20Khz, 775mV...5V)
Bass control : 20Hz / 250Hz turnover
0 / ±0,5 / ±1 / ±1,5 / ±2 / ±3 / ±4 / ±5 / ±6 / ±8 / ±10db
Treble control : 2,5Khz / 2Khz turnover
0 / ±0,5 / ±1 / ±1,5 / ±2 / ±3 / ±4 / ±5 / ±6 / ±8 / ±10db
Acoustic control : 70Hz or 300Hz turnovers
0 / ±0,5 / ±1 / ±1,5 / ±2 / ±3 / ±4 / ±5 / ±6db
Presence control : 2Khz or 4Khz turnovers
0 / ±0,5 / ±1 / ±1,5 / ±2 / ±3 / ±4 / ±5 / ±6db
Low filter : 12dB/octave
below 15Hz or 70Hz
High filter : 12dB/octave
above 8Khz or 12Khz
Oscillator frequencies : 70Hz / 333Hz / 1Khz / 10Khz / pink
Oscillator outputs : 150mV (rec out)
775mV (pre out)
0...775mV (external out)
Meters range : -50dB...+5dB
Meters display error : ± 1dB (-20dB...+5dB)
± 2dB (-20dB...-40dB)
± 3dB (-40dB...-50dB)
Meters response : 20Hz...20Khz (±1dB)
Meters rise time : 100µs
Meters decay : 1s
Volume attenuator accuracy : ± 0,5dB (0dB...-15dB)
± 1dB (-15dB...-30dB)
± 1,5dB (-30dB...-70dB)
Semiconductors : 90 FETs
143 transistors
55 diodes
2 Zener diodes
4 ICs
6 LEDs
PC : 55W
Dimensions : 46 x 17 x 38,9cm
Weight : 17kg.
page online since : 2006
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