Digital Do Main is a high-end company that's still unknown outside of Japan, but we'd be surprised if that remained the case after word gets out about the B-1a power amplifier.

Apart from being an oddly proportioned, but superbly built and finished integrated power amp with one input and a volume control, this is the first amplifier that we've seen that uses V-FET output transistors.

The V-FET is not a new type of transistor, but it has not been used in audio components since, at least, the early eighties. As a result the few amplifiers that have employed it have become cult classics with a few select online forums filled with discussion about their various merits.

The way in which Digital Do Main has resurrected the V-FET is not unlike the way in which another Japanese company, Audio Note (now KSL Kondo) brought the world's attention back to the single-ended triode amplifier in the eighties.

Whether the V-FET will enjoy such a successful revival remains to be seen, but if this transistor is the key to the sound of the B-1a, then it certainly deserves to.

As V-FET devices are no longer manufactured, DDM builds them itself which must make it unique in the world of hi-fi companies and beyond.

The company came to the attention of UK distributor ABC Audio because it makes a D-1 digital to analogue converter that incorporates MSB Platinum DAC modules and MSB is a key brand in ABC's portfolio (DDM also converts a Denon 2930 to act as an SACD player and is working on rebuilding a classic loudspeaker from the fifties called the RCA LC-1a).

Digital do main b-1a inner

The company's owner, Kazuhiko Nishi, founded the ASCII corporation, which had early ties with Microsoft and is now a listed multimedia company, so we can safely say that he's not in it for the money.

The B-1a is a 150-watt power amplifier with alternative RCA phono and XLR inputs, you could feasibly connect one source to XLR and another to the phonos if you wanted to use the amp as an integrated, but changing between them means reaching a small switch on the back panel, so this is not entirely practical.

However, by using the amp directly connected to a source gives better results than you can achieve with most preamps, so it's worth considering.

There are also volume controls on the rear panel, one for each channel and these can be used to adjust balance if required.

The B-1a can be used alone as a stereo or as a mono amplifier, or you can bridge it by adding a second B-1a and bolting the two together by replacing the panel opposite the power button with one that links the two units.

Operationally, there is a full on/off switch on the back panel and a standby button on the front. In standby mode the white light around the volume knob flashes on and off, like a very relaxed strobe light, which may not be to all tastes.

In true hardcore style there is no remote volume function – this product is about sound not convenience.

Sound quality

When the B-1a arrived we were in the process of reviewing the fabulous Vivid Giya loudspeaker and had been struggling to get as good a sound as had been produced by the next model down in the Vivid range, the K1.