A good control center must be able to preamplify program source signals faithfully without changing their characteristics. It must also be able to provide compensation, when required, for room acoustics or deficieciesin program source signals. To satisfy the first requirement of fidelity, a good control center must have excellent characteristics such as wide dynamic range, flat frequency response, low noise and low distortion as well as the ability to amplify and deliver a true replica of the input pulse signal. As for its second function of supplying compensation, it must have excellent equalization and other circuitry that can be finely adjusted, as well as efficient filters to cut off noise.
Moreover, a good control center must have plenty of input connectors, and its controls should be well laid out to avoid complexity.
Accuphase C-200, which was designed to serve as a top class control center, easily meets all these requirements, and more. Every stage is push-pull driven and powered by dual power supplies. Input voltages up to 400 mVrms can be handled, a maximum for equalizer amplifiers. Its 10 inputs and 7 outputs, and a total of 28 controls attest to its functional diversity. Yet it is simple to operate. Excellent design and full utilization of its front and front-sub panels have made this possible.
Originality Marks Equalizer Circuitry
A) Differential amplification push-pull circuitry throughout Direct-coupled, complementary symmetrical circuit in every stage assures very excellent fidelity and outstanding stability.
B) Easily handles dynamic range inputs.
Employment of complementary-symmetry Class A driver amplifier in the final stage and use of plus, minus dual power supplies enable the C-200 to handle wide dynamic range inputs as large as 400 mVrms at1kHz with distortion ratio less than 0,05%. This rating applies with the equalizer amplifier gain set at 40 dB. If it is set to 30 dB, input voltages up to 1,2 Vrms can be handled.
C) Low enhancement circuit has fine adjustment of "presence"
The C-200 is equipped with a Low Enhance switch which accentuates rich bass tones that add to music enjoyment. This switch offers selection of 0, +0,5 and +1 dB change against the RIAA characteristic curve at 100 Hz.
D) Disc input level control has 10 dB variation.
A 10 dB continuously variable attenuator is available to attenuate cartridge output, when excessive, to a siutable level. It also permits comparison of cartridges connected to Disc 1 and Disc 2, and equalization of their levels.
E) Disc input has impedence matching switch.
The C-200 is equiped with an impedance matching switch which provides selection of 30 K, 47 K and 100 Kohms input impedances at Disc 1. This makes impedance matching easy, especially to moving coil cartridges connected through step-up coupling transformers that require different optimum impedances depending on the make. It eliminates mismatching impedances at disc input connections which deteriorate sound quality.
F) Subsonic filter prevents intermodulation distortion.
Sunsonic vibrations of the turnntable motor, etc., when playing records,should be cut before they can enter the input since they may otherwise cause intermodulation distortion. The C-200 has a subsonic filter that provides this sharp cut-off at 25 Hz.
Wide Choice of Tone Variation
A) 10-step bass control, plus two turnover frequencies.
Every shade of bass tone variation is at your fingertips with the C-200 which offers 10-step rotary switch control for each channel, plus a choice of 200 Hz or 400 Hz turnover frequencies. These turnover frequencies provide a variation range of ±10 dB (at 100 Hz for 400 Hz turnover, at 50 Hz for 200 Hz turnover).
B) 10-step treble control, plus two turnover frequencies.
Likewise every shade of treble control is also available through 10-step selection for each channel, plus choice of 2,5 kHz and 5 kHz turnover frequencies that provide a variation range of ±10 dB (at 10 kHz for 2,5 kHz turnover, 20 kHz for 5 kHz turnover).
An independent switch is provided to turn the tone control circiut ON or OFF.
Low and High Filters
A) low Filter with 18 dB/oct cut-off at 30 Hz
The C-200 has a built-in low filter which can cut off at 18 dB/oct, all subsonic vibrations below 30 Hz which are likely to cause intermodulation distortion.
B) High Filter With 12 dB/oct cut-off at 5 kHz
It also has a 12 dB/oct cut-off High Filter for 5 kHz which very effectively cuts frequency noise without essentially affecting music quality.
Plenty of Input/Output Connectors
A total of 10 inputs and 7 outputs are available which should meet the needs of any assortment of program sources or sound equipment test connections. Of these, 3 inputs Mic, Aux and tape Play, and three outputs, Tape rec, Main Output, and headphone are conveniently available on the front sub-panel
Three tape Recorders Can be Connected
Inputs and outputs for connecting three tape recorders are available, of which two can be used for tape copying from one tape deck to the other. This function can be carried on while simultaneously listening to a different program source, since an independent tape copy switch is provided.
Complementary-Symmetry Circuit Headphone Amplifier.
A direct-coupled, complementary-symmetry circuit amplifier, made available exclusively for headphone use, upgrades the quality of headphone reproduction that is available through the C-200.
Well Regulated Power Supply
The well-regulated power supply is fully capable of supplying steady, non-fluctuating voltages to all amplifier stages and it is totally unaffected by any kind of input signal. This power supply is also capable of well-regulated performance even against reasonable AC line voltage fluctiations.
Speaker Switching Through Optional Relay Box.
In installations wher the power amplifier may not be close at hand, speaker selaction is possible through the C-200's front panel Speaker Selector switches when a Relay Box (optional ) is connected.
Specifications
Frequency Response:
High level Input : 20 - 20,000 Hz (+0; -0,2 dB)
Low Level Input : 20 -20,000 Hz (+0,2; -0,2 dB)
Distortion: Lower than 0,05% at rated output level 20 - 20,000 Hz
Input Sensitivity / Impedance:
Disc 1 ; 2-6 mV / 30, 47, 100 kΩ
Disc 2 : 2-6 mV / 47 kΩ
Mic. : 2 mV / 47 kΩ
Tuner : 200 mV / 130 kΩ
AUX 1 and 2 (front) : 200 mV / 130 kΩ
Tape Play 1 and 2 (front) : 200 mV / 130 kΩ
Maximum Input For Disc Input
400 mV RMS at disc level control miximum for 1 khz
1,2 V RMS at disc level control minimum for 1 khz
400 mV - 1,2 Vrms distortion ),05% at 1 kHz
Output Level and Impedance:
Main Output : 2,0 V / 200 Ω
Headphones : 0,4 V / 0,3 Ω
Tape Rec 1 and 2 (front) : 200 mV / 200 Ω
Mono Output : 0,42 V / 38 kΩ
Maximum Output Level: 10 Volts at 0,5% distortion
Voltage Amplification (in decibles)
Tuner, Aux, Tape Play Input :
20 dB to Main Output
0 dB to Tape Rec
6 dB to Headphones
Disc 1, Disc 2, Mic Input (at 1kHz):
60 dB to Main Output
40 dB to Tape Rec
46 dB to Headphones
Hum and Noise
Tuner, Aux, Tape Play : 90 dB below rated output
Disc , Mic. : 74 dB below 10 mV input
Bass Tone Controls:
Turnover Frequency 400 Hz : ±10 dB (2 dB step) at 100 Hz
Turnover Frequency 200 Hz : ±10 dB (2 dB step) at 50 hz
Treble Tone Controls:
Turnover Frequency 2,5 kHz : ±10 dB (2 dB step) at 10 kHz
Turnover Frequency 5,0 kHz : ±10 dB 92 dB step) at 20 kHz
Disc Low Enhancement (for Disc input):
0 dB, +0,5 dB, +1 dB at 100 Hz to RIAA standard characteristics.
Bass tone becomes richer when switched to =0,5 dB or 1 dB
Compensator:
ON position boosts low frequencies for low level listening.
+9 dB at 50 Hz (at volume control -30 dB)
Filters:
Disc Subsonic Filter : 25 Hz cutoff 6 dB/oct
Low Filter : 30 Hz cutoff 18 dB/oct
High Filter : 5 kHz cutoff 12 dB/oct
Volume Control: Less than 1 dB tracking erroe control down to -60 dB.
Power Requirement: Voltage selector for 100, 117, 220, 240 V 50/60 Hz operation
Power Consumption: 36 Watts
Semiconductor Complement: 80 Transistors, 35 Diodes
Dimensions (W x H x D): 445 x 152 x 355 mm (17½ x 6 x 14 inches)
Weight: 14 kg ( 30,8 lbs) net
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