Audio Database

C-2301 VINTAGE
Commentary

This control amplifier was developed by fully applying our accumulated advanced technology and know-how to solve the problem of how far the control amplifier can be refined.
The three elements of construction, quality parts, and circuit configuration are thoroughly pursued without compromise, and polished through repeated trial listening and improvement.

In addition to preventing interference between circuits and eliminating the influence of magnetic and electrostatic fluxes on sound, we are pursuing thorough vibration isolation.
First of all, we focus on the chassis structure. The main chassis is made of 1.2 mm thick pure copper plates. The L and R circuits are arranged above and below the pure copper chassis to eliminate interference between the left and right channels.
In addition, pure copper plates are placed on the bottom plate and input / output terminal panel to make the chassis non-magnetic and to reduce DC and AC impedance of the chassis body. Each amplifier block is made into a unit structure with electrostatic shielding by aluminum extruded material to eliminate the effect of jumping flux and vibration.
In addition, the suspension of the amplifier circuit board suppresses the vibration of the circuit board itself, and at the same time, to prevent the influence of external vibration such as sound pressure from the speakers, we have adopted a new surface contact bonding method.

In addition to resistors, capacitors and semiconductors, we use only carefully selected parts including transformer core materials, pin jacks and power cords.
Newly developed RMA resistance is adopted for the resistance, and it is a mold structure with increased vibration resistance, and the joint is gold-plated brass.
Capacitors include Great Pure Focus electrolytic capacitors, N-lambda capacitors, copper foil Mylar capacitors, and Styrofoam capacitors, all of which are newly developed and are of the highest grade with low distortion, high speed, and no resonance.
Two power transformers are mounted for L/R only, using a newly structured core with minimal leakage flux.
The master volume uses an ultra-high-quality detent type with improved sound quality, durability and accuracy. The resistor is gold-plated on a metal film evaporated on a glass epoxy plate, and the slider is a multi-alloy brush with 200 sliding elements.
The pin jack is machined from pure brass and plated with gold on top of copper. It is firmly screwed to the input / output terminal panel to prevent signal loss at the contact.
In addition, the balanced output terminal uses high-quality products for professional use made by Swiss-Noistrick.

In order to realize high S/N and wide dynamic range, all the equalizer amplifier, line amplifier and balance amplifier are push-pull configuration with pure A class cascode.
Especially in the circuit design, we take into account the current situation in which many input sources are directly input to the line amplifier, and the design is very much focused on the line amplifier.
In order to protect the purity of the sound, the number of contacts is increased unnecessarily, and the relay, which itself is harmful as a source of magnetic distortion, is eliminated. The signal circuit changeover switch uses a gold-plated magnetic material.
In addition, all power supply circuits, from the transformer to the rectifier circuit and regulator, are made independent of each other.
The MC transformer is composed of two independent L/R transformers for Low only and High only, and a total of four transformers is adopted.
The core material is made of original Super Permalloy with low strain rate, broadband characteristics and linear magnetic characteristics. In addition, special fillers are used to prevent unnecessary vibration, and the transformer body is housed in a case with a floating structure to prevent resonance.

A balanced amplifier circuit is adopted in which a pair of amplifier circuits are provided not only on the + side but also on the - side.
As a result, the signal system and the ground line can be completely separated, and problems caused by the ground line are eliminated.
Moreover, since the signal system is a completely closed loop, the influence of disturbances such as flux penetration on sound quality is reduced.
In combination with the power amplifier B-2301, it is possible to drive a complete balance from the line to the speaker output.

It is equipped with tape Route 3, Phono2 systems, Line 2 systems, CDs, Tuner 1 system each.
There is also an adapter connector that allows you to connect sound effects such as graphic equalizers and expanders.

Equipped with a source direct amplifier that can jump and output a line level amplifier. Equipped with an attenuator for level control.

Equipped with full mode of Normal/Reverse/L + R/L/R, it is convenient for balance adjustment in multi-channel systems.

Equipped with a center through balance volume, it does not pass through the balance attenuator at the center position and has an advantageous structure for sound quality.

Uses natural wood grain bonnet and side wood, glass front panel, and aluminum metal front panel.

Uses a solid metal cutting control knob.

A very thick power cord with polarity indication is used.

Model Rating
Type High-grade stereo control amplifier
Input Sensitivity / Input Impedance
Phono1, 2 MM : 2mV/47k Ω
High MC : 2mV/100 Ω
MC : 70 μ V/3 Ω, 200 μ V/30 Ω
Tuner, CD, Line1, 2, Tape Play1, 2, 3 : 150mV/47k Ω
Maximum Allowable Input (1 kHz, 0.01% THD) Phono1, 2 mm : 350 mV
Phono1, 2 High MC : 40 mV
Output Voltage / Output Impedance
Tape Rec(PIN) : 150mV/50 Ω
Control amplifier output Normal : 1.2V/50 Ω
Balance : + 4 dbm
Frequency characteristic Phono1, 2 mm : 10 Hz to 300 kHz ± 0.2 dB
Tuner, CD, Line1, 2, Tape Play1, 2, 3 : DC ~ 500 khz + 0 -3dB
Signal-to-noise ratio
(A network, short circuit)
Phono1, 2 MM : 90 dB
Phono1, 2 mc : 80 dB
Tuner, CD, Line1, 2, Tape Play1, 2, 3 : 110 dB
External dimensions Width 474x Height 160x Depth 422 mm
Weight 20.9kg