Yamamoto Sound Craft HA-02 Vacuum tube headphones/speaker amplifiers

For the amplification tube, only one miniature vacuum tube called Western Electric 408A is used. 300mW output is sufficient for headphone amplifiers. In addition, in the case of the speaker system, it is possible to listen to music with a small volume with this output. The noise characteristics of the 408A are excellent, and the resolution of small volume is excellent. Therefore, the advantage of BGM is that the sound is clearly reproduced even when the volume is narrowed. By utilizing the large amplification rate of the five-pole tube, we have succeeded in maximizing the freshness of sound by comprising only one stage of amplification circuit.

The high performance output transformer and Teflon insulated paper equivalent to the high-performance transformer of the advanced model are used for the output transformer of this machine, aiming for the highest sound quality. There are two types of terminals on the secondary side of the transformer, drawing output for 50Ω headphone amplifiers and 8Ω speakers.

The input of the HA-02 has a two-line terminal, which allows you to connect CD players and music players, and can be used by switching switches on the upper surface of the chassis. Most mobile devices such as i-pods can be connected using the included cable. It is also recommended to connect these portable devices and work and study while ringing the speaker as HA-02 BGM. When using HA-02 for headphones, the optimum load impedance is 50Ω, but it can support a wide range of impedance headphones from 8Ω to about 600Ω.

Our original chrome copper teflon insulation pin jack is used for HA-02 input terminals. In addition, the speaker terminal uses a gold-plated high-grade terminal that can connect speaker codes up to 5 mm in diameter, and the headphone jack uses a high reliability type from Neutrick.

The chassis of this machine is made of Comprit, which is popular even in A-08S, and it is an excellent material both electrically and intensively, impregnated with phenolic resin at high pressure in wood. In addition, African ebony material with high earthquake control effect which is popular as a setting base is used in the leg part rounded. The power transformer also features a high-performance R-core transformer. For rectification, the First Soft Recovery Diode separates the plate side and the screen grid side. A film capacitor is used to provide a high-quality power supply.

Use vacuum tube	Two WE408A included
Maximum output	Headphone terminal 300mW (at 50Ω load) Speaker terminal 240mW (at 8Ω load)
Frequency Characteristics	30 ~ 21,000 Hz (headphone terminal) 45 ~ 17,000 Hz (speaker terminal)
Residual noise	Headphone output speaker output
Input Impedance	50k Ω
Gain	Headphone output 9.5dB (at 50Ω load) Speaker output :1.5dB at 8Ω load
Size	150(W)325(D)125(H)mm
Weight	4.2kg

It is as if the HA-02 is super transparent as water and does not exist essentially as a regenerator. Listening sensitivity decreases during normal sessions. To compensate for this loss is the reason why the sound volume increases as the soundtrack of the film goes towards the end, but the HA-02 is forced to react opposite. As the track progresses, the music gets bigger. Why would that happen? When I derive it from the experience gained from the previous ears, it comes to the weight of the low range of the amplifier and speaker normally said. How much does this have to do with middle and low tones? The amount of weight and density of the low range projected on the vocal range has changed. However, it is different from the unnatural energy to increase the presence, so even such vocals do not bring tiredness and heat amount. It is not judged whether the bass is light and the middle sound range is colored. It involves the color temperature of the musical color. The palette HA-02 draw is incredibly rich, densely colored and perfectly consistent with the water-like transparency mentioned above.
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