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

Only one miniature vacuum tube from Western Electric called 408A is used for the amplifier tube. A 300mW output is sufficient for a headphone amplifier. In addition, with speaker systems, this output allows you to listen to music at a lower volume. The 408A has excellent noise characteristics and excellent resolution at very small volumes. Therefore, the advantage for BGM is that the sound is clearly reproduced even when the volume is reduced. Taking advantage of the large amplification factor of the pentapole tube, it has been constructed with only one stage of amplifier circuit, and has succeeded in bringing out the most freshness of the sound.

The output transformer for this unit is made of Teflon insulating paper, a high-performance output transformer equivalent to that of an advanced model, and aims for the highest sound quality. Two types of terminals are provided on the secondary side of the transformer, and outputs for 50Ω headphone amplifiers and 8Ω speakers.

The input section of the HA-02 is equipped with two terminals, allowing connections to CD players, music players, etc., and can be switched using the switch on the top of the chassis to be used. You can connect most portable devices such as i-pods using the included cable. The HA-02 is also recommended for connecting these portable devices and playing the speakers as background music to work and study. When using the HA-02 for headphones, the optimum load impedance is 50Ω, but it can be used with headphones with a wide range of impedances from 8Ω to 600Ω.

Our original chrome copper Teflon insulated pin jack is used for the input terminal of the HA-02. The speaker terminals are made of high-grade gold-plated terminals that can be used to connect speaker cords up to 5mm in diameter, and the headphone jack is made of a highly reliable Neutrick product.

The chassis of this machine is made by Comprite, which is also popular for its A-08S, and is an excellent material that is impregnated with phenolic resin at high pressure, making it an excellent electrical and strength material. The legs are also made from African ebony, which has a highly anti-magnetic effect, which is also popular as a setting base, and is made into a rounded process. In addition, the power transformer uses a high-performance R-core transformer. For rectification, a first soft recovery diode is used to separate the plate side and the screen grid side, bringing out the good sound of the pentapole tube. Film capacitors are used at key points for power sources to create a high-quality power supply circuit.

The HA-02 is as transparent as water, and it appears to be essentially absent as a regenerator. Listening sensitivity decreases during normal sessions. This is why the soundtrack of the film gets louder as it moves towards the end to make up for this loss, but HA-02 is forced to respond in the opposite way. As the track progresses, the music feels like it gets bigger. Why does this happen? If we derive from experience we've learned so far, we can see the weight of the low-frequency range of amplifiers and speakers, which are usually said to be the case. How much does this have to do with the mid-range and low-high ranges? The amount of weight and density of the low range projected onto the vocal range is a bit odd. However, since it is different from the unnatural energy that increases its presence, even such vocals do not bring fatigue or heat to listen. Whether the bass is light or not is not a judgement of whether the midrange is in the color. This has something to do with the color temperature of the musical colour. The palette depicted by HA-02 is incredibly rich, densely colored, and perfectly matches the aforementioned water-like clarity.
*sixmoon.com