The use launches the sockets for the
vacuum tubes of 3 difficult types because there is not a socket
They are the new type of the vacuum tube for an audio. Are all of you knowing the thing called the door knob vacuum tube? There are 2 kinds of 316A and 388A as a large type and there are 368A (S), 703A as a small type. These vacuum tubes are the vacuum tube that Western Electric did the form like the UFO, with the transmitting tube that designed for the radar. These were hardly used for for the audio heretofore. Although this vacuum tube is doing such a form we have such a characteristic that even the value of μ able to use fairly even for for proper and audio with the direct heated toriode. The plate dissipation has the big value called 30W with 25W, 316A with 703A that is not believed from this size. Even I like this unique attractive form. It becomes to recent and etc. made of Tung-Sol understand that there is the vacuum tube fairly abundantly, although there are few numbers and the Western Electric production reached to the conclusion that we are able to use as for the audio if there is the socket. Even that makes the sockets of these door knob tubes is not so difficult because it is manufacturing the socket made of the Teflon the various kinds in our company. Trying to make the socket with the experimental production a little to try there we would try to search the birth and sound of these tubes.
703A (Tung-sol) has Ef: 1.15V, If: 4.5A,
Eb: 450V, Ib: 57mA, μ: 10, Gm: 2500μ mhos, Rp: the rating called
4000Ω. The output of about 1W was obtained with Rp: 5k Ω at the
time of Eb: 377V, Ib: 38mA, grid voltage-21.6V in actual action
condition. Even a usual CR connection almost thinks with same
although this is the test in the direct association amplifier
of our company.
Also, 316A (Tung-sol) has Ef: 2.0V, If: 3.65A, Eb: 450V, Ib: 80mA, μ: 6.5, Gm: 2400μ mhos, Rp: the rating called 2700Ω. The output of about 1.5W was obtained with Rp: 5k Ω at the time of Eb: 410V, Ib: 33mA, grid voltage-32V in actual action condition. As for these characteristics, the sound is good although it comes off with the clear, although the output of much is not said, the height of the freshness is impressive and I liked very much. μ of raising it with the transmitting tube the big output called about 7W was obtained when compose the kathode follower circuit to the try with WE417A and try to drive with the direct association because the that vacuum tube hears such a good conversation well that give a favor of driving it in the low impedance circuit such as the kathode follower. The action condition of the case is Eb: 374V, Ib: 68mA, grid voltage-12V, Rp: 5k Ω. Although the sound becomes a little bit softer sound compared with the original circuit of the direct association the force was able to confirm that is able to compete sufficient with 300B etc. if it is this with the full marks. Although it is contrastive with the impression called firm clear sound more more compared with the vacuum tube for the audio such as 300B the superiority or inferiority thought that it is not attached. When only this sound comes out well from the plate that there is only 300B of about 1/20 we admire. Probably the person who saw it first will not be believed.
We felt it when that is appearing in the sound because these vacuum tubes are doing original simple structure. The distance of the heater and grid near the heater is as one of the DC ignition is good because the heater ham seems to come out because or a little.
We decided the development of the amplifier that used those vacuum tube socket and, 316A in our company based on this result. We launch and precede the socket in the meantime although the time is required to the development of the amplifier a little more. These vacuum tubes are able to prepare even a highly efficient heater transformer (\9,000) with the small size of 703A and 316A combined use because the heater constitution is original. Interest of you are and please contact the one.
The socket for EL152/EL153 of the simultaneous
launching is the one that manufactured it in answer to such a
voice that almost there is not a socket, although good EL152 made
of the Telefunken seems to be appearing fairly cheaply recently.
EL152 is the beam output tube of plate dissipation 40W according
to the data and the output of 18W seems to obtained with the A
class single. Over KT-88 etc. amplifiers might be possible produce
if we make it well because it is made of the Telefunken of the
purity with the highly efficient tube close to KT-88 and F2A etc.,
in terms of the performance. Please try it once by all means.
About the acquisition of the vacuum tube, 316A sells the part because it has the stock of the degree that is our company. Also we send the copy to the one who hopes the data (the English sentence) of the door knob tube. (We request the carriage with the actual expenses)
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