"2A3" single stereo amplifier with input volume A-011SS

- It is the precious power amplifier which can be obtained now and which can substitute almost without adjustment of a 2A3 vacuum tube, and can carry out sound / highest a comparison audition.
Although we could accept the sound by A-08SS of the previous work and the glorious prize was obtained, taking advantage of the technology, the amplifier which furthermore, raised sound quality appeared in 2A3 vacuum tubes as A-011SS.
A-08SS had a case where the real value was not demonstrated, by the inefficient speaker for only 2W output.
The 2A3 vacuum tube adopted as this machine has a twice about as many output as 4W and A-08SS.
In a vacuum tube, if an output called these 4W is a remarkable size and is a speaker of the efficiency of a degree in the middle, it is a level which can be used enough.
Moreover, it is produced mostly, since it can obtain that it is comparatively cheap and, the new vacuum tube newly designed not only in a vintage tube but in every country in the world exchanges and hears an output tube various type, and is easy for a 2A3 vacuum tube.
In this machine A-011SS, it is designing so that almost all the vacuum tubes marketed may be substituted and heard by no adjusting and may be made.
The circuit composition which does not need troublesome ham adjustment etc. is adopted, and you can use almost all commercial 2A3s, without caring about a noise.
I indicate the actual measurement of the noise on the right.
- The product made by U.S. Vishay and the super-high performance thin film resistor were adopted, and it asked for the highest sound.
Shin Film Resistor (thin film resistor) of Vishay is adopted as almost all portions also with this machine as highly efficient parts in which the superiority was accepted by A-08SS of the previous work.
This resistor is a very excellent resistor designed and manufactured with the newest technology.
Usually, as for the temperature coefficient, 50-200 ppm is the error of the carbon resistance used with vacuum tube amplifier, or metal skin membrane resistance common about 1 to 5%.
Comparing with it, Shin Film Resistor of Vishay is 0.1% of an error. It excels very much with the temperature coefficient of 10-25 ppm.
About the temperature change when current flows into a resistor, this temperature coefficient means what% resistance changes, if it goes up by 1 degree.
When this temperature coefficient was bad and the electric signal by music is added, resistance will change and distortion will arise in sound.
Since this appears when the music signal changed momentarily is added, it is a portion which does not appear in the usual rate of distortion.
Moreover, this resistor is excellent also in noise and is the feature also with big a noise also being reduced by about about of the usual metal tunic resistor 1/ 10.
In this machine, this is adopted also as cathode division resistance of an output tube, and sound quality is raised.
- The SIC Schottky diode was adopted only as the driver tube as another circuit, and the improvement in sound quality was achieved.
Although 80 high rectifier tubes of evaluation are used for the output stage of A-011SS, the rectification circuit which uses the SIC Schottky diode made to become independent is adopted as the driver stage.
The leak current of the letter of a spike always generated at the time of rectification has the outstanding performance in which it hardly generates, and is very excellent in the SIC diode also in sound quality with the usual diode.
At us, the audition of many SIC diodes was repeated and, finally the product of Infinion of Germany is adopted.
The musical amount of information is improving greatly by separating the power supply of the output stage through which big current flows, and the driver stage of a small signal.
- All the vacuum tubes to be used were considered as DC ignition, and adoption and an energetic sound have been obtained for the Schottky diode of super-low impedance.
The heating circuit of 717A and a 2A3 vacuum tube was considered as DC ignition of both waves rectification in order to hold down a noise to the minimum, and the large scale Schottky diode was adopted as the rectifier by the super-low loss.
In A-011SS, the force on account of the low impedance is charm.
Moreover, since the ham balancer usually used spoils sound quality, it is not used.
- Sound which adopted the cut core power transformer and the PTFE (fluoro-resin) insulation High-B type cut core output transformer, and was excellent was realized.
The cut core transformer excellent in the regulation High-B type was adopted as both the power transformer of this machine, and the output transformer.
The core material of made-to-order 100-micron thickness was adopted especially as the output transformer, the coil was wound around it using the insulating paper of PTFE (fluoro-resin), and sound quality was raised.
- The high-quality sound part collected from all over the world was adopted as the key point, and the highest sound quality was aimed at.
The capacitor and the resistor currently used for this machine have selected carefully and adopted the part of the highest sound quality selected from every country in the world by audition.
Especially the capacitor is using the polypropylene type which was excellent in sound quality.
In A-011SS, adoption and use of the chemical capacitor which is inferior in sound quality are reduced mainly for the film capacitor as much as possible not only to a signal course but to the power supply circuit.
Moreover, the resistor is also carrying out careful selection use of the high-quality sound parts, such as metal clad resistance of DALE, and mass surface mount resistance by Vishay.
- Fluoro-resin insulation of the U.S. MIL specifications and standards and silver plating copper wire were adopted as internal wiring material, the fluoro-resin was adopted also as the socket, and the highest sound quality and reliability were pursued.
To the internal wiring material of this machine, fluoro-resin insulation and silver plating copper wire are raising adoption, sound quality, and performance extensively.
Since a fluoro-resin hardly lets air pass, the internal copper wire can maintain early performance, without rusting.
Since the copper wire of general vinyl covering tends to let air pass, it may have a bad influence also on sound quality by aged deterioration.
Moreover, in A-011SS, the gilding socket of fluoro-resin insulation is extensively adopted also as a socket, and a sound quality side and reliability are raised sharply.
- The tube protector made from the Africa ebony is made the root portion of the output tube with adoption and an intrepid style.
The tube protector made from the Africa ebony is made the attachment portion of the output tube 2A3 vacuum tube with the impressive design which is not in adoption and others.

- A-011SS standard

formal: -- 2A3 single stereo power amplifier /use vacuum tube: -- two 2A3s (it not being attached and there being also - or a RCA2A3 attached type) and 717A:2 80:1 / maximum output: -- 4W+4W frequency characteristic: -- 20-30kHz (at the time of 1W output) / input sensitivity: -- at the time of 0.4V input
4W output / gain: -- 23.5dB / remains noise: -- about 0.7 -- mV / input volume: -- 100komega volume / input impedance: -- 66komega / outside dimension: -- 400 (W) -- 294 (D) -- 204 (H) / weight: -- 14.3kg