|480,000 yen(October, 1995 release)
Control amplifier which enriched many characteristics further with following the
balance transmission technology of C-290, and constituting this from a current
feedback magnification circuit.
Although it is pure line amplifier composition, playback of an analog disc
is also attained by optional exclusive phone equalizer unit AD-275.
The balance transmission system is used for a
line amplifier part.
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 this circuit, it has a relation of tucking up its sleeves with a cord
that 2 sets of amplifiers feed back each output to the other party, and
the +-symmetrical signal is sent out by low impedance. + Since the symmetrical
signal of - is the circuit by which floating was carried out from the ground,
even if it grounds one side of an output, both of amplifier operates and
an Output voltage does not change.
The balance output unit adopts a
current feedback magnification circuit, and constitutes it from a discrete part
which thought sound quality as important.
This circuit lowers the impedance
of the input terminal by the side of a return, detects current, carries out I-V
conversion of that current with a transformer impedance amplifier, and is making
the output signal.
In this circuit, since it is hard to generate phase
rotation since the impedance of a return input portion is very low, and there is
almost no necessity for phase compensation, it excels in the response
characteristic over an incoming signal, and power is demonstrated to the music
playback containing many pulse ingredients.
The amplifier circuit
consists of right-and-left a total of four unit amplifier, such as line-in and a
balance output, and was stored in aluminum housing which carries a broadband
constant-voltage power source, it was fixed to the mother board of glass epoxy, and the resonance and the mutual intervention by vibration are prevented.
Moreover, a power transformer and a filter capacitor are also considered as
right-and-left independence, and electric interference and mechanical vibration
are suppressed by having perfect monophonic composition according to the
framework structure by the hard aluminum of 8mm thickness.
purity copper wire is adopted as a power cord.
Moreover, connection of a
commercial cord is also possible by a connector system.
Since a straight
signal course is constituted at the shortest, without taking about a signal
course, the logic relay control system which controls a relay electronically has
The encapsulated type relay for communication industry was
adopted as the relay used here, and the contact has acquired low contact
resistance and quantity durability by the plated with gold and the crossbar twin
system to it.
The phase switch which reverses the phase of the whole
equipment is carried.
The change method does not have degradation of sound
quality only for replacing + and - of the balance amplifier input unit.
Tone control of the added type active filter system currently used for
the full-scale graphic equalizer etc. is adopted as tone control.
A flat [
original ] tone control [ this ] signal is a system which passes straight, is
another, makes the characteristic if needed, and is adjusted from a flat signal, and serves as predominance in respect of sound quality.
formed only in headphone.
The output to a speaker can be cut and it can
carry out variable [ of the headphone output ] in main volume.
The small resistance object of a distortion is adopted especially as volume.
Volume operation with attached remote control is performed in the
combination of this volume controller and a small motor with a clutch.
||3Hz-350,000Hz+0 -3.0 dB
||0.005% (with all the input terminals)
|Input sensitivity/input impedance
Output power / output 0.5V)
|An Output power/Output load impedance
||Balanced/Unbalanced Output: 2.0V/50 ohm
Tape Rec (at the time of AD input): 252mV/200 ohms
|S/N / input conversion noise
||Input short-circuit, IEC-A compensation
Rec(at the time of AD input): 6.0V
|Minimum load impedance
||Balanced/Unbalanced Output: 600ohm
Input->Balanced/Unbalanced Output: 18dB
(100Hz), +6dB (20kHz)
||Turnover frequency and variable range
Bass: 300Hz, ±10dB (50Hz)
Treble: 3kHz, ±10dB (20kHz)
||10Hz, -18 dB/oct
||Conformity impedance, 4ohm-100ohm
|Power supply voltage
||At usually, the time: Width 475x height 150x
depth of 404mm
At the time of AD-275 extension: Depth of 413mm
||At usually, the time: 19.7kg
At the time
of AD-275 extension: 20.4kg
||Exclusive phone equalizer unit AD-275 (\100,000)
|Attachment: Remote commander RC-10
|Remote control system
||Infrared pulse system
||direct-current3V Battery: UM-4(IEC name R03)
|The maximum Dimensions
||Width 66x height 175x depth of 20mm
||190g (Battery included)