Yamamoto Sound Craft A-08S WE101D/104D Single Stereo Amplifier WE101D Vacuum Tube Included Used Item
Product code: 101d-5Yamamoto Sound Craft A-08S WE101D/104D Single Stereo Amplifier WE101D Vacuum Tube Included Used Item
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Power amplifier dedicated to WE101D/104D
A-08S Western Electric 101D/104D Version
Yamamoto Sound CraftThis is a listening unit that was installed in a listening room. Since it was used by the manufacturer for audition purposes, maintenance is thorough. It is a very pristine unit. The usage at the manufacturer’s headquarters was very limited, so the included WE101D ST vacuum tube has very little usage. It will be shipped after manufacturer maintenance. A 6-month manufacturer warranty is included, covering the output vacuum tubes as well.
This is a sister model of the A-08S dedicated to WE101D and WE104D. Although its output is less than 1W, the sound quality is excellent, comparable to the WE205D. During the prototype stage, it exceeded expectations in sound quality and output, ensuring it is fully practical, which led to its commercialization.
The approximately 0.25W low output of the WE101D is applied to a plate voltage with a 250V load, drawing 13.5mA, resulting in a power consumption of about 3.5W. At this time, the load impedance is 5k ohms, producing approximately 0.6W of output. On the other hand, the WE104D, according to its specs, achieves about 0.8W output at a plate voltage of 190V, so this is adopted as is. For both types, the plate current value is fine-tuned with the cathode resistor to achieve an optimal value, producing about 0.8W output according to specifications. Additionally, by simply switching the cathode resistor, both vacuum tubes can be used.
| Vacuum Tubes Used | WE-101D/104D*, C3m, 80 |
|---|---|
| Maximum Output | WE101D: approx. 0.6W/8Ω WE104D: approx. 0.8W/8Ω |
| Frequency Response | 22Hz-28kHz (-3dB) |
| Output Transformer Impedance | Primary: 5kΩ, Secondary: 8Ω |
| Residual Noise | 0.4-0.8mV |
| Drive Method | CR coupling, self-bias method |
| Size | 400(W)294(D)204(H)mm |
| Weight | 14.3 kg |
Incredibly sensational!!
The 101D is far better than the 300B. It's the best amplifier I've ever used.
My impression of amplifiers using the WE101D is that, except when playing at very high volumes, they provide the most dynamic and clear sound of all amplifiers from the same company, including the WE205D, 45, and 300B. This seems to be largely due to the non-choke power supply of this amplifier. In typical amplifiers, a choke coil is used to remove the ripple from the B power supply of the output stage, but since this amplifier uses a small current, it forms the filter and supplies the B voltage using only CR components instead of a choke coil.
The cathode bypass capacitors in the output stage are American Dearborn lug-type polypropylene capacitors, enclosed in a bakelite case with high-strength epoxy resin by our company, which also greatly contributes to the sound quality. Additionally, this amplifier uses a Siemens vacuum tube called C3m as the driver tube, with its shield case removed. The C3m, released around 1968, is a relatively new design pentode with excellent characteristics, producing clean sound with minimal noise, making it a superb tube.
We tested both the ST-type and tennis ball-type for the WE101D and WE104D. The ST-type provides a tight, well-defined sound, whereas the tennis ball-type delivers a more relaxed, spacious sound. Although the tennis ball-type is visually interesting and fun to look at, it is expensive; for sound quality, the ST-type is sufficiently satisfying. The speaker terminals are only for 8Ω output, but you can use 4Ω or 16Ω speakers without any problem. However, in any case, the maximum output will decrease. For an 8W maximum output, the actual output would be around 4-6W.
