Yamamoto Sound Craft YDA-01B vacuum tube output circuit DA converter

WE Bring Out the Charm of Five Pole Tube Sound

Designed to use two Western 408A five-pole tubes
The vacuum tube uses Western Electric's high-performance five-pole tube WE 408A. The DA converter's output is loaded with resistance and directly connected to the input part of the vacuum tube. The current to the screen grid, which greatly affects the sound quality, is supplied through a constant current circuit by MOS FET, improving the purity of the sound. The heater circuit is supplied independently by double wave rectification with a large Schottky diode. The design policy incorporates a method to reduce the number of elements used to the limit, simplifying the circuit and maximizing the purity of sound.

Mono PCM1794A to DA Converter IC s

The output of the PCM1794A DA converter IC has four output parts for operating output in mono configuration, but only one of them is used, and other terminals are not used with a dummy resistor. It is a seemingly unnecessary use method, but the purity of sound is higher than parallel connection.
Supplied from a separate regulator circuit eliminates power interference with the circuit

The power transformer employs a large-capacity toroidal transformer, which separates the analog and digital winding and reduces interference between the two. The transformer is a careful power supply circuit that separates the digital part, the analog part, and the output circuit from the separate regulator. Teflon insulation and silver-plated copper wire are used for wiring materials with extremely high reliability and excellent sound quality.

Digital Input Terminal	Coaxial 1 system (RCA)
Analog Output Terminal	Coaxial 1 system (RCA)
Output Level	4V/0dB
Use vacuum tube	WE408A x2
Corresponding frequency	32-192kHz (auto-follow)
Sampling Filter	8X Oversampling Digital Filter
Frequency Characteristics	20~20kHz(±1dB)
SNR	78dB (IHF-A waght)
Output Impedance	2.6kΩ
Size	420(W)290(D)94(H)mm/5.2kg

I would like to think that it is based on the intention to proactively reflect this five-pole tube, not only on simple tubular seasoning, that the character was made using the ball called "WE408A." For example, high-range information quantity, range, etc.YDA-01It is more abundant. However, on the other hand, the low-range thickness and calm energy balance of the waist seem to be sufficiently drawn out the taste of the vacuum tube. In particular, the thick tone with low range power may be large according to the WEI ball.
It is easy to understand the difference when listening to jazz. The wood-based touch and the depth of the pitch remain unchanged, but the sound is thick once and the sound of the torso is felt thick. The same can be said for piano tone and kick drum instantaneous power. It is a good impression of some kind of melody. Even in the orchestra, the sound of the bass strings lowers the center of gravity, and on the strings and woodwinds, along with the richness of moisture, is a glossy cut.YDA-01In contrast to the delicate softness, it is characterized by an instantaneous cut and clarity of strength. If you listen to music with a modern and well-prepared response,YDA-01But you should say orthodoxy. However, I do not get tired of that, and I think that the YDA-01B model will show its appeal when seeking a certain kind of hot air and powerful expressiveness in music. I also want to note that it is not "old sound." Basic performance supported by high precision devices and powerful power supplies ensures accuracy of reproduction.
*STEREO SOUND