Audio Database

The

Accuphase C-265
330,000 yen(March, 1997 release)

Description

The control center which constituted the line amplifier part from a current feedback magnification circuit, and was developed aiming at serious consideration of a quality, and high-quality sound reproduction following balance transmission technology.

adoption s The current feedback (current feedback type) magnification circuit which returns an output signal in the form of current is in the line amplifier part.
In this circuit, the impedance of the input terminal which is a return side was lowered, current was detected, I-V conversion of that current was carried out with the transformer impedance amplifier, and the output signal is made. In this circuit, since the impedance of a return input portion is very low, it is hard to generate phase rotation and, as a result, there is almost no necessity for a phase guarantee.
For this reason, many characteristics have been sharply improved by a little NFB, it excelled in dynamic characteristics, such as a standup, and the natural energy response is realized.

The balance output circuit of a bridge feedback system is adopted.
Balance transmission is a system which sends simultaneously the positive/negative symmetrical signal which the phase reversed mutually, and is excellent in the capability to remove the noise ingredient in the common mode.
2 sets of amplifier, amp1 and amp2, is prepared for balance transmission, and the symmetrical signal of +- is sent out by low impedance C-265 as a relation of tucking up its sleeves with a cord which feeds back each output to the other party. Since the feature of this circuit is carried out [ floating of the symmetrical signal of +- ] from the ground, even if it grounds one side of an output, both of amplifier operates and an Output voltage does not change.

A line amplifier part is a pure complimentary push pull circuit, and constitutes this from a discrete part by a current feedback magnification circuit. The phase guarantee of each stage could be offered light by this, and more natural sound quality has been obtained.
Moreover, the balance input amplifier which had a gain before volume was placed, and S/N in the practical use region which extracted volume is improved by arranging this line amplifier after volume.

C-265 consists of right-and-left a total of six unit amplifier of balance input amplifier, line amplifier, and balance output amplifier. It fixed by thick aluminum extrusion material so that a mutual intervention might not be carried out, and these unit amplifier has prevented resonance by external vibration.

Right-and-left independence is used also with a power transformer and a filter capacitor, and it has monophonic composition completely electrically.
The cross talk between channels which passes a power-source part by this is stopped.
Furthermore, the mutual intervention between amplifier is prevented by carrying a broadband power supply circuit for exclusive use in each unit amplifier.

Since a straight signal course is constituted at the shortest, the logic relay control system has been adopted.
The sealed type relay for communication industry is adopted as the relay used for this, and contacts are a plated with gold and a crossbar twin system, and have realized low contact resistance and quantity durability.

The amplifier only for headphone is formed and high-quality sound-ization is attained.
Moreover, it is possible to cut the output to power amplifier with an output on/off switch, and to carry out variable [ of the headphone output ] in main volume.

The added type active filter system is adopted as tone control.
From this system, it passes straight, and if needed, an original flat signal is another, and makes the characteristic, and the characteristic is adjusted with making it adjust from a flat signal by it.

Two balance inputs are carried.

The high-quality sound type using the small resistance object of the distortion is adopted especially as volume. Volume control by a remote commander is enabled by combining this volume controller and a small motor with a clutch.

The rear panel is equipped with the slot which can extend the option board corresponding to an AAB standard.


Rear Option
An
Attached Unit Use Balance

Rating of a mode
(The analog disc characteristic is the characteristic at the time of input board AD-10 extension)
Form Stereo control amplifier
Frequency response
Balanced, Unbalanced : 3Hz-350kHz+0 -3.0 dB
20Hz-20kHz+0 -0.2 dB
AD input: 20Hz-20kHz±0.2dB
THD 0.005%
Input sensitivity/impedance
(An Output power / 0.5V output)
AD MM: 8.9mV/2.2mV/47kohm
AD MC: 0.25mV/0.063 mV/10ohm, 30ohm, a 100-ohm change
Balanced: 252mV/63mV/40kohm
Unbalanced: 252mV/63mV/20kohm
An Output power/impedance Balanced, Unbalanced output:2V/50 ohm
Tape rec (at the time of AD input): 252mV/320 ohms
S/N, input conversion noise
Input short-circuit and A-compensation EIA S/N
At the time of an Output power S/N Input conversion noise
AD MM: 92dB -133dBV 85dB
AD MC: 75dB -147dBV 80dB
Balanced: 106dB -118dBV 99dB
Unbalanced: 105dB -117dBV 99dB
Maximum-except-take-off level
(Distortion 0.005%, 20Hz - 20kHz)
Balanced, Unbalanced output:6.0V
Tape rec:6.0V
Minimum load impedance Balanced, Unbalanced output: 600ohms
Tape rec: 10kohm
Gain Balanced, Unbalanced input -> Balanced, Unbalanced output: 18dB
AD MM input -> Balanced, Unbalanced output: 47dB
AD MC input -> Balanced, Unbalanced output: 78dB
Tone control Low-pitched sound (300Hz): ±10dB (50Hz)
Loud sound (3kHz): ±10dB (20kHz)
Loudness Compensation + 6dB (100Hz, Volume-30dB)
Attenuator -20dB
Headphone jack Conformity impedance: 4ohms - 100ohms
Power source AC100V, 50Hz/60Hz
Power consumption 17W
The maximum Dimensions Width 475x height 150x depth of 404mm
Weight 15.8kg
Attachment: Remote commander RC-20
Remote control system Infrared pulse system
Power source DC 3V
Battery AA -- type (SUM-3/R6) and two pieces
The maximum Dimensions Width 55x height 194x depth of 18mm
Weight 100g (Battery included)
Option: Option board
The Line-in board Line-10 (8,000yen)
The common high-level input terminal of an imbalanced system.
Analog signals, such as CD player and a tuner, are played.
The Analog disc input board AD-10 (50,000yen)
All cartridges are supported by loading of a highly efficient high gain equalizer.
With an internal DIP switch, a MM/MC change, MC input impedance, and Subsonic-Filter on/off can be set up.

MM Gain: 29dB
Input impedance: 47kohm
MC Gain: 60dB
Input impedance: 10, a 30 or 100-ohm change