Audio Database

The

Accuphase C-220
220,000 yen(June, 1977 release)

Description

Control amplifier only for a disc developed as a preamplifier only for a record.

record playback -- since a special-purpose machine, neither the aux terminal nor the tape input terminal is carried. Instead, if the power switch of C-220 is turned OFF, the terminal direct connected to power amplifier is prepared. It is connecting with the control amplifier which has already possessed the tuner and the tape recorder using this, and connecting the amplifier output to EXT.Preamp Input of C-220,The output of the already possessed control amplifier can connect with power amplifier automatically.
Moreover, when rectifying a frequency response by tone control, it is possible to use it as equalizer amplifier by connecting with the aux input of the control amplifier which takes out a signal from Fixed Output of C-220, and has already been possessed.

The head amplifier for MC cartridges is built in and, in 26dB and from an equalizer to an output, head amplifier is giving a gain of 60dB.
Moreover, head amplifier was changed by relay control, by electronic, a muting relay and time lag of the output were given and the shocking noise is canceled so that proper use of MC and MM can be performed with one arm.
Contact resistance selects carefully and uses for the relay little relay which was excellent in durability over a long period of time.

Circuit composition is using what improved further based on P-300 and the whole page symmetry push pull circuit developed by C-200.
the base before this circuit applies NFB -- since the characteristic is excellent, the low distortion is expectable that much as a result. Furthermore, this circuit is strong also to power-supply-voltage change, and stable operation is possible for it.

Each unit amplifier including head amplifier is considered as direct-current amplifier composition which removed the capacitor of NF loop by the Class-A drive.

The input unit of head amplifier constitutes the symmetry push pull differential amplification using four RET (ring emitter transistor) developed as an object for high frequency electric power magnification. Furthermore, it has Class-A direct-current amplifier composition which took out the output by pure complimentary.
RET has structure which carried out 100-piece parallel composition of the transistor unit for small signals through ballast resistance of the emitter by a diffusion layer. Electric power magnification is possible, maintaining the high frequency characteristic with which the transistor for small signals is equipped by this. This RET was adopted as the entrance of head amplifier with the smallest signal level, and reduction of a large noise level is realized. Furthermore, by sending large current through a magnification element, a circuit is formed into low impedance, the impedance of the NFB input side of differential amplifier is lowered, and the noise which a circuit generates is reduced sharply.
The characteristic whose input conversion noise of a head amplifier part is actual measurement-154dBV (0.1mV of rated inputs, S/N74dB) and which was excellent is realized.

The input unit of the equalizer amplifier part is taken as the input direct connection circuit in the differential amplification circuit combining the FET buffer.
Moreover, pure complimentary connection of the RET which excelled [ output ] in the high frequency characteristic is made, an Output load impedance is lowered by large current drive, and low impedance-ization of NF loop is enabled.
Thereby, the input conversion noise of equalizer amplifier has realized -140dBV (2mV of rated inputs, S/N86dB) with the actual measurement.

The power-source part is attaining stabilization with direct-current servo amplifier, and makes impedance of each frequency as low as possible from direct current to the super-high region.

The canon connector output is also carried in the output simultaneously with the usual RCA pin jack.

A design has two kinds, 19-inch rack-mounted type A type and B type of a side plate, as well as the multichannel divider F-5.


The Rear
Chassis
Chassis
The
The

Rating of a mode
Form The preamplifier only for a disc
Frequency response 20Hz-20kHz±0.2dB
THD (20Hz - 20kHz, Output power) 0.01%
A rated input / impedance DISC1, 2 (Head amp off):2.0mV/100 ohm, 30kohm, 47kohm, 100kohm
DISC1, 2 (Head amp on):0.1mV/100 ohms
An Output power/impedance Main output: 2.0V/50 ohm (Volume maximum, the rated input)
Fixed output: 150mV/200 ohms
Minimum load impedance Main output: 5.0kohm
Fixed output: 10.0kohm
S/N
(at the time of input short-circuit, an IHF-A curve, and a rated input)
Head amp off:85dB
Head amp on:72dB
Input conversion noise
(Input short-circuit, IHF-A curve)
Head amp off:-139dBV
Head amp on:-152dBV
the maximum input (1kHz, 0.01% of distortion) Head amp off:400mVrms
Head amp on:20mVrms
The minimum input level 10Vrms (20Hz - 20kHz, 0.01% of distortion)
Gain (DISC input->Main output) Head amp off:60dB
Head amp on:86dB
Volume control linkage error Less than 1dB
balance adjustment (right and left) 0, -0.5, -1.0, -1.5, -2.0, -3.0, -4.0, -5.0, -6.0, -7.0dB, -infinity
The semiconductor used Transistor: 109 pieces
FET: 16 pieces
Diode: 34 pieces
Power supply voltage AC100V/117V/220V/240V, 50Hz/60Hz
Power consumption 65W
Dimensions A type: Width 482x height 82x depth of 345mm
B type: Width 445x height 82x depth of 349mm
Weight 10.7kg