The charm of highest vacuum tube VT-52 with which Western Electric hid was pulled out to the maximum extent.
VT-52 Single Stereo Amplifier A-010

- Single stereo amplifier which uses VT-52 in which Western Electric hid distinguished

VT-52 is the trilateral output tube which the Western Electric developed as military. Since it was seldom manufactured by any makers other than a Western Electric unlike general noncommercial 2A3 etc. and most Specifications tables whose notability is formal low again do not remain, it has been called the triode of a phantom. However, the VT-52 has been handed down from generation to generation as an exlent vacuum tube which hid among maniacs as a triode with wonderful sound quality. The structure and the quality of the material of the vacuum tube of VT-52 resemble the stamp type of WE300B with the highest evaluation very much also in the vacuum tube of a Western Electric, and many WE300B stamp types and common features are seen also for the sound quality. The base portion is displayed as VT-52 by the stamp and WE VT-52 makes it hear also from this about it.

Moreover, the heater electric power of VT-52 has a bigger value than 7V, 1.1A, and that 300B. This appears as room of sound to the output. Since the characteristic resembles 45 vacuum tubes, VT-52 is also called a supermarket 45. However, although the ability shows the performance certainly exceeding 45 and has the sound quality of a record level also in the triode to many, it is not an overstatement. This machine was designed for the purpose of demonstrating the performance of such VT-52 to the maximum extent.

- The improvement in sound quality was greatly achieved by using four 80 for a rectifier tube, being attached to one amplification pipe and using one rectifier tube. The rectifier tube of A-010 employed 80 full time four times. There are two reasons in this. It is for one separating a driver tube and an output tube with other amplification parts, respectively, and using them in the highest state. When a big music signal is inputted, a big current change arises in an output tube. When the number of power supplies is one, the current change affects a driver tube. This machine may not be a value in which the influence is so big because of Class A single amplifier. However, current change of a driver tube is sure to have influenced for a small level called 1/10 or less of an output tube . If the power supply part after a rectifier tube is separated, respectively, most of the influence will be lost. By this, the vacuum tube of each stage can hardly be influenced by other vacuum tubes, but can carry out ideal amplification operation. Another reason is for making speed of response of a power supply quick. Usually, the power supply part of the plate circuit of a driver tube consists of RC filters which use a resistor and a chemical capacitor. In that case, a small current change is provided with the current from the electric charge stored in the chemical capacitor. A current change big on the other hand is consumed with the current from a rectifier tube. Since the working speed of charge and discharge is slow, the chemical capacitor may generally be unable to follow a quick change of a music signal. Therefore, at our company, the film capacitor of small capacity has been adopted also as a driver tube from the former. This view is promoted and only the film capacitor of a value as small as only 2 micro F constitutes the input capacitor of these 80 rectifier tubes from the driver tube A-010. And the highly efficient current regulator of the U.S. IXYS Company is adopted, and it is clear and is considered as the power supply part which was excellent in speed of response. Moreover, since it was the same, the choke coil of the output circuit was abandoned and the filter circuit only by RC was constituted. It succeeded in obtaining the clear sound which amplifier's own working speed improves and is speedier with the composition of these power supply parts.

- The German highly efficient pentode C3m was adopted as a driver tube, and stability was aimed at the improvement in sound quality, and over a long period of time. A-010 adopted the highly efficient German pentode C3m as a driver tube. C3m is the high reliance and highly efficient vacuum tube used for the telecommunications companies in Germany. Our company is most excellent in in having tested, the life of 10,000 hours is guaranteed, and sound quality can also expect the long-term stable use. - Adoption and a clean and energetic sound have been obtained for DC ignition and the constant current circuit of heating circuit of all the vacuum tubes. The heating circuit of C3m and VT-52 vacuum tube was considered as DC ignition by both waves rectification in order to hold down a noise to the minimum, adopted the constant current circuit using MOSFET, and used it as the heater power supply whose speed of response it is clean and is quick. The element of the U.S. IXYS Company was altogether adopted as the rectifier and the constant current element. IXYS Company is the maker who is manufacturing the business-use highly efficient semiconductor, a common article is large and difference performance and sound quality are very excellent in the rectifier, MOSFET, etc.

- Sound which adopted two R core power transformers and the cut core output transformer of a High-B type excellent in the regulation, and was excellent was realized. Two R core transformers were adopted as the power transformer of this machine. It considered so that the transformer of a high-pressure part and a heating circuit might be separated in a power transformer part and each might not influence each other. It considered so that current change of a plate power supply circuit might not influence a heating circuit. Moreover, the cut core transformer of the High-B type excellent in the regulation is adopted as an output transformer and a choke coil. The core material of made-to-order 100-micron thickness was adopted especially as the output transformer like A-08S etc., the coil was rolled using the insulating paper of Teflon, and sound quality was raised.

- The high-quality sound part and custom-made part which were collected from all over the world were adopted as the key point, and the highest sound quality was aimed at. The capacitor and the resistor currently used for that of this machine have selected carefully and adopted the part of the highest sound quality selected out of every country in the world by the audition. The capacitor of the principal part is using it for it by the epoxy resin further, carrying out sinks in of the polypropylene type which was excellent in sound quality to an ebony case. Since an electrode vibrated easily, the film capacitor achieved the big improvement in sound quality according to this sinks in effect. The capacitor of most including the power supply currently used for A-010 is reducing use of the chemical capacitor which is inferior in sound quality as these film capacitors made from special as much as possible. Moreover, the resistor is also carrying out careful selection use of the high-quality sound parts, such as winding resistance of U.S. DALE, metal clad resistance, mass surface mount resistance which are acknowledged by the good thing of sound quality.

- A-010 Specifications
Form: WE VT-52 single stereo power amplifier *Use vacuum tube: WE VT-52 2pcs. C3m 2pcs. 80tubes 4pcs. *Maximum output: 3W+3W *Frequency characteristic: 20-22kHz (at the time of 1W output) *Input sensitivity: the time of 0.4V input 3W output *Gain:24.5dB *Remains noise: about 1mV * input impedance:200k ohm *Outside dimension: 400 (W) 314 (D) 211 (H) *Weight: 16.3kg

The site where the detailed information about VT-52 is published.

The vacuum tube production technology of WesternElectric at the time of the height of prosperity has crystallized both WEVT-52 this stamp base portion and the hook up portion of a heater, from the photograph left.