Audio Database

The

Accuphase C-275V
530,000 yen(May, 2000 release)

Description

Control amplifier which refined all the circuits of C-275, and also raised completeness based on the technology of C-290V.

The current feedback type magnification circuit which returns an output signal in the form of current is adopted.
In this circuit, the impedance of the input terminal by the side of a return was lowered, current was detected, and the output signal is made by carrying out I-V conversion of that current with a transformer impedance amplifier. Thereby, since the impedance of a return input portion is low, many characteristics are [ that it is hard to generate phase rotation ] sharply improvable by a little NFB.

The 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.
In C-275V, it has a relation of tucking up its sleeves with a cord which feeds back each output of 2 sets of amplifier to the other party, and the symmetrical signal of +- is sent out by low impedance. Since 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.

The line amplifier part has adopted the pure complimentary push pull circuit, constitutes this from a discrete part by a current feedback magnification circuit, and makes phase compensation of each stage light.

The printed circuit board by a Teflon (woven glass fabric fluoro-resin) base is adopted as a signal transmission circuit.
Teflon has the features, like heat resistance and the high frequency characteristic with very little (low loss) leak current with a low (high propagation velocity) dielectric constant are excellent. SN on Hearing impression is improved by using this Teflon base for an audio circuit.

Right-and-left independence is achieved also with a power transformer and a filter capacitor, and it has perfect monophonic composition electrically.
Furthermore, the broadband low impedance power source was carried in all the unit amplifier, and the mutual intervention between amplifier is prevented.

The amplifier circuit of C-275V consists of right-and-left a total of four unit amplifier, such as line-in and a balance output, and has the composition of having given each the exclusive power-source part.
It stored in thick aluminum housing and fixed firmly so that these unit amplifier might not carry out a mutual intervention, and resonance by vibration is prevented.

Since a straight signal course is constituted at the shortest, the logic relay control system has been adopted.
The encapsulated 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 added type active filter system is adopted as tone control.
When passing an original flat signal as it is and changing the characteristic, from this system, the characteristic is made if needed, and it is made to change according to making it adjust from a flat signal by it.

The exclusive headphone amplifier circuit which thought sound quality as important is built in.

The Compensation and Subsonic Filter which can choose an output phase change button and three kinds of characteristics are carried.

Volume and the remote commander in whom an input change is possible are attached.

Although C-275V has composition only for a line, record playback is possible by extending optional exclusive phone equalizer unit AD-275V from the rear panel side.
A Teflon (woven glass fabric fluoro-resin) base is adopted as a printed circuit board, and the influence from the outside is suppressed by storing this in a strong aluminum case. The connector of the DIN standard was adopted as connection with a main part, and the fall of the signal to noise ratio is prevented by connecting a magnification circuit with an input terminal by a curtate distance.
It has the input circuit for exclusive use united with the cartridge of each MM/MC in this phone equalizer unit, and a two-kind choice is possible also for three kinds and a profit in MC input impedance.

AD-275V cannot be used for any models other than C-275V and C-275.
Moreover, AD-275 can be used for C-275V.


Rear The
An
Relay AD-275V

Rating of a mode
(The analog disc characteristic shows the time of AD-275V extension)
Form Stereo control amplifier
Frequency response
Balanced, Unbalanced : 3Hz-300kHz+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: 4.0mV/1.0mV/47kohm
AD MC/60dB: 0.25mV/0.063 mV/10ohm, 30ohm, a 100-ohm change
AD MC/66dB: 0.125mV/0.0315 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/200 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: 90dB -138dBV 91dB
AD MC/60dB: 79dB -151dBV 84dB
AD MC/66dB: 75dB -153dBV 84dB
Balanced: 114dB -126dBV 96dB
Unbalanced 116dB -128dBV 96dB
Maximum-except-take-off level
(Distortion 0.005%, 20Hz - 20kHz)
Balanced, Unbalanced output:6.0V
Tape rec(at the time of AD input): 6.0V
The AD maximum inlet pressure
(Distortion 0.005%)
MM input:125mV
MC(60dB/66dB) input:8mV/4mV
Minimum load impedance Balanced, Unbalanced output: 600ohms
Tape rec: 10kohm
Gain Balanced, Unbalanced input -> Balanced, Unbalanced output: 18dB
Unbalanced input -> Rec output: 0dB
AD MM input -> Balanced, Unbalanced output: 54dB
AD MM input -> Rec output: 36dB
AD MC(60/66dB) input -> Balanced, Unbalanced output: 78/84dB
AD MC(60/66dB) input -> Rec output: 60/66dB
Compensation
(Volume -30dB)
1:+3dB(100Hz)
2:+6dB(100Hz)
3: +6dB (100Hz), +6dB (20kHz)
Subsonic Filter 25Hz, -12 dB/oct
Attenuator - 6dB-20dB-30dB
Power source AC100V, 50Hz/60Hz
Power consumption 25W
The maximum Dimensions Width 475x height 150x depth of 404mm
At the time of AD-275V extension: Depth of 413mm
Weight 21.7kg
At the time of AD-275V extension: 22.5kg
Attachment Remote commander RC-26
Option Phone equalizer unit AD-275V (100,000yen)