Engineers at UK-based loudspeaker maker NXT have developed a stereo amplifier module that delivers audio power of 15W per channel from a standard USB port.
Incorporating NXT’s recently acquired Audium amplifier chip, the DyadUSB amplifier module has been matched to NXT’s Balanced Mode Radiator (BMR) speakers that use the company’s patented Bending Wave Technology.
The company says that the DyadUSB modules can be designed into compact desktop and travel speakers to deliver Hi-Fi where an external power source is undesirable and where minimal power consumption is needed to extend battery life, without compromising audio fidelity.
The optimisation for use with BMR drivers includes the option of on-chip digital filtering for acoustic voicing, bass enhancement, stereo widening and driver protection, as well as implementation of a Zobel network to match the driver’s inductance to the amplifier’s output drive.
The DyadUSB platform has been announced less than five months after NXT acquired IP from Audium Semiconductor, developers of the amplifier chip upon which the design is based.
The Audium amplifier chip is claimed to be 20 times more efficient than competing devices, thanks to patented techniques that minimise both fixed power losses and output-dependant variable power losses. The chip uses power rail switching so that the amplifier operates efficiently from a low-voltage supply most of the time but an on-chip DC-DC boost converter drives its output transistors on audio peaks.
The DyadUSB platform is currently being demonstrated to key customers and mass production is planned for early 2011. The amplifier, complete with a pair of 40 x 40mm BMR drive units, will cost approximately $50 (£32) in 100+ quantities.