Audio Database

The

Accuphase AD-250
30,000 yen(June, 1994 release)

Description
 
The exclusive phone equalizer unit which enables playback of an analog record by C-250.
Record playback is attained by extending from the rear panel side.

AD-250 equips the printed wired board of the glass substrate formed into the golden plate with the exclusive input circuit which matched the cartridge of each MM/MC.
It is made to consistent with the high-output impedance of a cartridge at the time of MM input, and it has FET composition of high S/N.
Moreover, since a minute signal is received by low impedance, the difference input circuit by a low noise element is constituted, it is attaining low impedance-ization of a NFB loop at the time of MC input, and it is enabling little reproduction of noise.

Selection of the MC input impedance 10, 30, and 100ohm and the Subsonic Filter which cuts a super-low-pass noise are carried in the core.
Before these functions equip with AD-250, they can be set up with the switch in a printed circuit board.



Rating of a mode
(at the time of C-250 connection)
Form The phone equalizer unit only for C-250
Frequency response AD Input: 20Hz-20kHz±0.2dB
THD 0.005%
Input sensitivity
(an Output power / 0.5V output)/impedance
AD MM: 8.0mV/2.0mV/47kohm
AD MC: 0.25mV/0.063 mV/10ohm, 30ohm, 100ohm
S/N
Input short-circuit, IEC-A compensation (at the time of a rated input) AD MM:95dB
AD MC:79dB
EIA S/N AD MM:88dB
AD MC:85dB
Input conversion noise
(input short-circuit, IEC-A compensation)
AD MM:-137dBV
AD MC:-151dBV
The AD maximum inlet pressure
(1kHz, distortion 0.005%)
MM:250mV
MC:8mV
Gain AD MM Input->Balanced/Unbalanced Output: 48dB
AD MM Input->Rec Output: 30dB
AD MC Input->Balanced/Unbalanced Output: 78dB
AD MC Input->Rec Output: 60dB
Subsonic Filter 25Hz, -12 dB/oct
(It sets up with the core DIP switch of AD-250)