Yamamoto Sound Craft
A-08S WE101D/104D Single power amp
Yamamoto Sound Craft A-08S WE101D/104D Single power amp
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WE101D / 104D dedicated amplifier
A-08S Western Electric 101D/104D version
It is a sister amplifier of A-08S for exclusive use of WE101D and WE104D whose output is smaller than WE205D which has been highly evaluated.The output is less than 1W, but the sound is as good as WE205D. At the prototype stage, it was commercialized because it had sound quality that exceeded expectations and sufficient output to withstand practical use.
WE101D's low output of about 0.25W is loaded with about 250V as plate voltage, and 13.5mA is passed to make the power consumption about 3.5W.At this time, the load impedance is 5k ohm, and the output of about 0.6W is obtained.On the other hand, since the maximum output of WE104D is about 0.8W at a plate voltage of 190V, the same state is used.For both types, the plate current value is obtained by finely adjusting the cathode resistance to obtain the optimum value, and the output is about 0.8 W as specified.Also, both vacuum tubes can be used simply by switching the cathode resistance.
WE101D and WE104D are very similar in appearance, but their characteristics and sound are very different, and you can see that they are vacuum tubes with completely different personalities.Compared to WE101D, which features a powerful and energetic sound like masculine, WE104D has the impression of a feminine, gentle and soft sound.When comparing the two, the position of the preamplifier's volume must be changed significantly due to the large gain difference.If you listen at the same position, the volume will be too different and the WE104D will sound like it's not powerful.As an impression, WE104D has too little gain, so it seems better to use 2.5k ohms for the output transformer.
|Heater voltage||4.5VDC||4.5V DC||4.5V DC||4.5V DC|
|Plate load impedance||5k ohm||5k ohm||5k ohm||5k ohm|
|Cathode voltage (bias voltage)||-27V||-27V||-58V||-58V|
For the output stage cathode bypass capacitor, the use of a type of Derborn lug terminal type polypropylene capacitor sealed in a bakelite case with high-strength epoxy resin also greatly contributes to sound quality.In addition, this machine uses a Siemens C3m vacuum tube as the driver tube with the shield case removed.C3m is a relatively new pentode that was released around 1968. It is an excellent vacuum tube with very good characteristics, clean sound and little noise.
Both WE101D and WE104D tested the ST type and the ball type, but I felt the ST type was a good tight sound, and the ball type was a rough and spacious sound. The ball type is interesting to see and fun, but since it is expensive, I felt that the ST type would be sufficient if it was selected from the sound quality.
|Vacuum tubes||WE-101D/104D*, C3m,80|
|Maximum output||WE101D:0.6W/8 ohms WE104D:0.8W/8 ohms|
|Output transformer impedance||Primary side 5k ohms, Secondary side: 8 ohms|
|Drive system||CR coupling, self-bias method|
**Since it will be made to order, the delivery time may take more than 3-4 months.