COLUMBIA PMA-300
¥ 39,800 (around 1971?)
Commentary
A pre-main amplifier that achieves both high performance and excellent cost performance.
The circuit structure adopts a two power supply type differential-amplification all-stage direct connection pure complimentary service OCL circuit.
The equalizer amplifier section is designed with special emphasis on the dynamic range and equalizer characteristics. The circuit configuration is a 3-chip E-E feedback type using specially selected silicon transistors. The power supply voltage is approximately 40 v.
The tone amplifier section has a 3-chip configuration with an FET in the middle. The collector current of the in the first stage is reduced to operate in a region with low noise level. In addition, it is designed with a power supply voltage of 40 v like the preamplifier to obtain a wide dynamic range and excellent linearity.
Also, in consideration of connecting with a multi-amplifier circuit, an emitter follower is used to extract the tone control characteristics so that external loads do not affect them.
In addition, the tone control knob has an 11-position click stop.
Model Rating
| Type | Pre-main amplifier |
| Circuit configuration | Differential-Amplified OCL circuit for all stages directly connected pure complimentary service 2 power supply system |
| Power Amplifier Unit | |
| Rated output | Single-channel Operation : 22W/22W (8 Ω, 0.1% distortion factor) Both channels operating : 18W + 18W (8 Ω, distortion factor 0.1%) 21W + 21W (8 ohm, EIAJ, 5%) |
| Harmonic distortion factor | 0.1% or Less (at Rated Output) 0.03% or Less (at 0.3W ~ 18W Output) |
| Cross modulation distortion factor | 0.1% or Less (at Rated Output) |
| Frequency characteristic | 8 Hz ~ 150 kHz + 0 dB at 1W Output |
| Input impedance | 82k Ω or more |
| Damping factor | 70 or More (1 Hz ~ 10 kHz) 50 or More (1 Hz to 50 kHz) 20(100kHz) |
| Input sensitivity | 1 V (Output 20 V) |
| Residual noise | 0.1 μ W or Less (8 Ω) |
| Signal-to-noise ratio | 90 dB or more |
| Preamplifier Section | |
| Output (harmonic distortion rate 0.1% or less) | 10V(100Hz) 10V(1kHz) 5V(10kHz) |
| Harmonic distortion factor (at output 1 V) | 0.03%(100Hz) 0.024%(1kHz) 0.028%(10kHz) |
| Cross modulation distortion factor | Not more than 0.1% |
| Frequency characteristic | Aux : 15 Hz ~ 70 kHz (Power amp 8 Ω Load) |
| Input sensitivity | Phono1 : 2mV/60k Ω Phono2 : 8mV/60k Ω Aux1/2 : 100mV/100k Ω |
| Maximum Undistorted Allowable Input (1 kHz) | Phono1:200mV Phono2:600mV |
| Equalizer characteristic | RIAA deviation within ± 1 dB |
| Signal-to-noise ratio | Phono1 : 70 dB or more |
| Tone control | Bass : + 9.5 dB ~ -11dB (100 Hz) Treble : + 10 dB ~ -9dB at 10 kHz |
| Filter | Low Filter:-7dB(50Hz) High Filter:-6dB(7kHz) |
| <General> | |
| Input terminal | Phono1/2, Aux1/2, Tape Play (RCA) |
| Output terminal | Rec out, Speaker out (2 systems), Pre amp out |
| Recording and reconnector | Rec/PB (DIN terminal) Input sensitivity : 100 mV Output level : 30 mv |
| Semiconductor used | Transistor : 25 Diode : 14 pcs IC : 1 |
| AC outlet | Switched : one system Unswitched-One system total:350W |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Power supply fuse | 2.3A |
| Power consumption | 10W (No Signal) 55W (at 1/3 rated output) |
| External dimensions | Width 370x Height 141x Depth 310 mm |
| Weight | 7kg |