| Vacuum Tube Audio |
It was about 50 years ago that I first made a vacuum tube amplifier using GT-tubes of 6V6 and 6SN7.
But the world changed to the digital times and my audio system went to the semiconductor type.
About ten years ago I found several web sites which introduce how to make vacuum tube amplifiers. Finally I
began to make vacuum tube amplifier again because of much nostalgia in the old technology.
In this site some handmade vacuum tube amplifiers are presented including preamplifier, measuring equipment,
and speaker system.
Until now I have tried to introduce various circuits in order to improve the electrical performance of vacuum tube amplifier. However, even if I invested big money and being brought close to the sound of semiconductor amplifier, I perceived that it is meaningless. Recently I am trying to make amplifiers with simple classic circuit in quest of the "vacuum tube-like sound".
Until now I have tried to introduce various circuits in order to improve the electrical performance of vacuum tube amplifier. However, even if I invested big money and being brought close to the sound of semiconductor amplifier, I perceived that it is meaningless. Recently I am trying to make amplifiers with simple classic circuit in quest of the "vacuum tube-like sound".
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Since I obtained two composite triode tubes of 6CS7,
I modified 300B single CR coupled amplifier to make trans-driven amplifier. I had experience the driver
of 6BM8 with triode connection, but I expected that pure triode tube will give me better sound.
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I made an 811A amplifier to hear the sound of the tube with
thorium-tungsten heater. Although the figure of damping factor is only 1.5, 811A amplifier plays a splendid
sound in combination with the Tannoy Stirling speaker. (Not existing because of reconstruction)
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At the age of 70, I made 211 single amplifier as "this is
the last tube amplifier in my life". I made it at a low cost less than the price of one output transformer
of TANGO or TAMURA, while paying attention to electric shock since it has a plate voltage close to 1,000V. |
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(1) I was interested in making a vacuum tube OTL amplifier,
but I hesitated to make it from the aspect that more than 10 vacuum tubes line up. However, a hybrid OTL amplifier
which obtains 20 W output by the combination of 4 vacuum tubes and semiconductor driver was introduced in the
MJ magazine, so I challenged to make it. (Not existing because of reconstruction)
(2) Although the sound of all-stage differential push-pull amplifier was clear and nice, when the 1626 all-stage differential push-pull amplifier with very small power consumption was completed, it became fiewer turns. So I reconfigured to the trans-driven push-pull amplifier, but I felt a little shortage of bass sound, finally I converted it to the normal CR-coupled push-pull amplifier again. |
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I bought 4 cute ST tubes called 1626 so I modified 6CL6 all-stage differential push-pull amplifier. It could be remodeled with minimal circuit modification just by enlarging the hole of the socket. The output power has dropped to one-third of the 6CL6 amplifier, but it turned into the healing amplifier. (It has been remodeled to the normal push-pull amplifier later.) |
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I am listening to Japanese popular song and NHK midnight radio while sleeping on the bedside stereo device. I wanted to listen quietly with better sound so I made my own headphone amplifier with op-amp and vacuum tube types. When listening to the comfortable sound, I often go to sleep. |
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(2) FET Differential Preampifier |
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(1) I made this preamplifier with interest of differential amplification.
I installed the bass boosting circuit, which is favorite to me. Afterwards I replaced 12AU7A and variable
resistor with 6DJ8 and hand-made resistance attenuator, respectively. (Not existing because of reconstruction)
(2) Although the sound of 6DJ8 differential preamplifier was wonderful as expected, when using of semiconductor main amplifier, there is a problem that some noise is conspicuous at the time of maximum volume. Then, I decided to modify it to an FET differential preamplifier aiming at "mild preamplifier." |
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I found many web sites where various cheap digital amplifier kits are introduced. Therefore I bought "TA2020-020 Digital Amplifier Complete Kit" of Wakamatsu Inc. for the first trial. |
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I tried to play analog record after 35 years' absence. As a result I found that I can enjoy it even in the records I bought for 100 yen per piece. Enka of Mr. Masuiyama is very good! In addition, both MM and MC cartridges can be used, and auto stop function was newly installed. |
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I replaced the master clock of SONY's CD player CDP-X55ES with a high-precision clock. As a result, the sound quality and skip of sound when performing the CD have been improved. |
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(2) JBL Speaker System |
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(1) There are two audio systems in my home. Usually I listen to
jazz music using the main system and FM radio by subsystem. (2) I, who have audio hobby and like jazz music, have wanted to challenge JBL speaker system for a long time and finally decided to make it. |
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I have only minimum quantity of measuring equipment necessary to make the vacuum tube amplifiers. Old and hand-made measuring instruments are presented here. |
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I summarized the outline and features of single amplifier, push-pull amplifier, and differential push-pull amplifier. |