Yamamoto Sound Craft A-08S-205D Single Stereo Amplifier
Product code: 205D-1Yamamoto Sound Craft A-08S-205D Single Stereo Amplifier
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This is a made-to-order product. The estimated delivery time is around 5 months.
Dedicated power amplifier for WE205D
A-08S Western Electric 205D version
The WE205D is an excellent amplifier, but its output is only about 1W. Therefore, the choice of speakers is limited. High-efficiency speakers such as Altec, JBL, and Rauscher are suitable. These speakers have high conversion efficiency and good sensitivity, allowing for a smaller amplifier output. However, on the flip side, the amplifier's noise will also be correspondingly higher.
Generally, the WE205D can maintain a relatively low noise level even with AC ignition, but due to variations in vacuum tubes and other reasons, there tends to be variation in output noise with AC ignition. Therefore, the company has changed the ignition method of the WE205D to a DC ignition method using Schottky diodes with full-wave rectification, which yielded good results in the A-09. To simplify the circuit, a constant voltage circuit was not adopted, and only diodes and capacitors were used. This allowed the residual noise to be reduced to 0.4-0.6mV. The voltage supplied to the WE205D was also slightly increased, resulting in a maximum output of about 1.3W. The rectifier tube was changed from 5U4G to the clearer-sounding 80. Additionally, the front stage circuit uses DC ignition, and the capacitors are enclosed in a specially made ebony case, along with improvements to the output transformer, using the highest quality components throughout.
Furthermore, a current meter has been placed on the chassis to allow for constant monitoring of the output tube's current. The operating condition of the precious WE205D vacuum tube can be checked, and its approximate lifespan can be judged using this current meter.
These improvements have resulted in a sound that is more dynamic and powerful. When listened to with our large 3-way speaker system or ALTEC605A, it produced a much stronger and clearer sound than the 300B.
Operating conditions for WE-205D
- Plate Voltage: 380V
- Plate Current: 25mA
- Plate Loss: Approximately 9.5W
- Rp: 5k ohms
- Rk: 1.25k ohms
- Drive method: CR coupling self-bias method
| Used vacuum tubes | WE-205D (round type sold separately), WE-717A, 80 |
|---|---|
| Maximum output | 1.3W/8Ω |
| Frequency characteristics | 22Hz-30kHz (-3dB) |
| Input sensitivity | 4W output at 0.4V input |
| Residual noise | 0.4-0.6mV |
| Size | 400(W) 294(D) 204(H) mm |
| Weight | 14.3kg |
