Vintage Pioneer "Series 20" C-21 // Solid-State Preamplifier

SOLD , now part of a Private Collection
The C-21 preamp was one of the original four pieces included in the sought-after Pioneer Series 20, a line of true audiophile components from the late '70s. Take a peek at the specs, but this preamp certainly pushes the envelope. As far as frequency response with minimal distortion, you would be hard-pressed to find a comparable preamp at this price.
Production
1976-80
Condition
8/10
Serial No.
ZC1161376
Restoration
  • Full 30-point service check
  • Replaced power indicator light
  • Replaced power cable
  • Cleaned controls, switches, and chassis
Factory Specs

Type   Solid State Preamplifier

Phono input level   2,5mV / 100 Ohm

Phono input resistance   100 Ohm / 10k / 25k / 50k / 75k / 100kOhm

Phono input capacitance   100 / 150 / 200 / 300 / 400 / 500pF

Phono maximum input level   300mV (0.01% THD, 1Khz)

Line inputs   150mV / 50kOhm

Tape output   150mV / 1kOhm

Preamp output   1V / 450 Ohm (50kOhm load, nominal); 20V / 150 Ohm (50kOhm load, maximum)

THD   0.006% phono (1V output, -20dB vol., 0dB gain control); 0.005% line (1V output, 0dB gain control)

Frequency response   20Hz - 20Khz (RIAA, ± 0,2dB); 10Hz - 100Khz (line, +0 / -0,2dB); 3Hz - 300Khz (line, +0 / -1dB)

S/N ratio   80dB phono (1V output, IHF A); 100dB line(1V output, IHF A)

Subsonic filter   6dB / octave below 6Hz

Semiconductors   36 transistors, 47 diodes

Power Consumption   10W

Dimensions   16.53"W x 3.25"H x 14"D

Weight   14 lbs.

Documentation

Pioneer C-21 Schematic

The History of Pioneer
Pioneer was founded by Nozomu Matsumoto in 1938 in Tokyo as a radio and speaker repair shop. In December 1953 Mr. Nozomu Matsumoto succeeded in developing the first domestic dynamic speaker made of original parts. It was named A-8 and marketed in Japan under the Pioneer brand. It later became the origin of the HiFi ...
[ Read More ]
Liner Notes

Class A SEPP two-stage current mirror differential circuits for both phono and flat amp sections, ultra parts with ±1% tolerance polypropylene caps and ±100ppm /C° metal film resistors, ±37V phono stage power supply and two constant voltage main power supplies. Even more important is the volume attenuator which 2 gangs of 32 steps made of silver printed contacts - same as that of a Sony TA-F7B. Both were sourced from ALPS.

Stock No.
7940474568925
The C-21 preamp was one of the original four pieces included in the sought-after Pioneer Series 20, a line of true audiophile components from the late '70s. Take a peek at the specs, but this preamp certainly pushes the envelope. As far as frequency response with minimal distortion, you would be hard-pressed to find a comparable preamp at this price.

Production

1976-80

Condition

8/10

Serial No.

ZC1161376

Restoration

  • Full 30-point service check
  • Replaced power indicator light
  • Replaced power cable
  • Cleaned controls, switches, and chassis

Factory Specs

Type   Solid State Preamplifier

Phono input level   2,5mV / 100 Ohm

Phono input resistance   100 Ohm / 10k / 25k / 50k / 75k / 100kOhm

Phono input capacitance   100 / 150 / 200 / 300 / 400 / 500pF

Phono maximum input level   300mV (0.01% THD, 1Khz)

Line inputs   150mV / 50kOhm

Tape output   150mV / 1kOhm

Preamp output   1V / 450 Ohm (50kOhm load, nominal); 20V / 150 Ohm (50kOhm load, maximum)

THD   0.006% phono (1V output, -20dB vol., 0dB gain control); 0.005% line (1V output, 0dB gain control)

Frequency response   20Hz - 20Khz (RIAA, ± 0,2dB); 10Hz - 100Khz (line, +0 / -0,2dB); 3Hz - 300Khz (line, +0 / -1dB)

S/N ratio   80dB phono (1V output, IHF A); 100dB line(1V output, IHF A)

Subsonic filter   6dB / octave below 6Hz

Semiconductors   36 transistors, 47 diodes

Power Consumption   10W

Dimensions   16.53"W x 3.25"H x 14"D

Weight   14 lbs.

Documentation

Pioneer C-21 Schematic

The History of Pioneer

Pioneer was founded by Nozomu Matsumoto in 1938 in Tokyo as a radio and speaker repair shop. In December 1953 Mr. Nozomu Matsumoto succeeded in developing the first domestic dynamic speaker made of original parts. It was named A-8 and marketed in Japan under the Pioneer brand. It later became the origin of the HiFi ...
[ Read More ]

Liner Notes

Class A SEPP two-stage current mirror differential circuits for both phono and flat amp sections, ultra parts with ±1% tolerance polypropylene caps and ±100ppm /C° metal film resistors, ±37V phono stage power supply and two constant voltage main power supplies. Even more important is the volume attenuator which 2 gangs of 32 steps made of silver printed contacts - same as that of a Sony TA-F7B. Both were sourced from ALPS.

Stock No.

7940474568925

Vintage Pioneer "Series 20" C-21 // Solid-State Preamplifier
Vintage Pioneer "Series 20" C-21 // Solid-State Preamplifier
Vintage Pioneer "Series 20" C-21 // Solid-State Preamplifier
Vintage Pioneer "Series 20" C-21 // Solid-State Preamplifier
Vintage Pioneer "Series 20" C-21 // Solid-State Preamplifier
Vintage Pioneer "Series 20" C-21 // Solid-State Preamplifier
Vintage Pioneer "Series 20" C-21 // Solid-State Preamplifier
Vintage Pioneer "Series 20" C-21 // Solid-State Preamplifier
Vintage Pioneer "Series 20" C-21 // Solid-State Preamplifier
Vintage Pioneer "Series 20" C-21 // Solid-State Preamplifier

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