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Yamamoto Sound Craft : Vacuum tube Headphone amplifier HA-02


HA-02 is the headphone amplifier which uses a vacuum tube as an amplification element. Although output power is small, it has the output terminal for speakers and it can also sound a speaker with small volume as BGM.

Only one right and left are using each the miniature vacuum tube 408A of a Western Electric for an amplification tube. Although this WE408A is a vacuum tube of a vintage, it is one of the produced vacuum tubes, and since it was used abundantly for telefon equipment, there are no worries about a spare tube even now. It seems that it was used for various uses in order to often tend to use characteristics, although this vacuum tube is originally designed as an object for high frequency amplification. When it was used for the data of a Western Electric as a small output tube, there was description that about 300mW output power was obtained. When we manufactured the amplifier for headphone based on this description, we decided to produce commercially, since the good result was obtained.

Available on backorder

SKU: Yamamoto HA-02 Categories: , Tags: , ,





300mW output power can be called sufficient output power for headphone amplifier. Moreover, it is also possible to listen to music with smaller volume by this output power also in a speaker system. Although it is impossible to take out big volume which is usually heard from a speaker, of course, when telephoning as BGM, it can be said to be sufficient value to use it on a convenient level. Moreover, originally, since this vacuum tube was developed as an object for small signals, noise characteristics are also excellent, and the resolution at the time of very small volume is excellent. Therefore, the place where sound is clearly reproduced also where volume is lowered as an object for BGM can call it an advantage. Moreover, although the amplification circuit of a two or three stages is used in many cases, in the case of this machine, the big amplification factor of a pentode is used, and it usually constitutes it from vacuum tube amplifier in only one stage of amplification circuit. It has succeeded in pulling out the freshness of the simplicity, therefore sound to the maximum extent.

The output transformer highly efficient despite small size is adopted as the output transformer of this machine using the same technology as the transformer adopted as the high-end model kind of our company. It was adopted as A-08S etc., the high Teflon insulating paper of evaluation was adopted as this output transformer, and the highest sound quality was aimed at.

Additional information

Weight 3.5 kg
Dimensions .0325 × 0.150 × 0.125 cm