The company has published a technical reference document about its new patented Class AD Polyphase proprietary amplifier development on its website.
The new topology – which is said to yield ‘major improvements’ in sound quality, efficiency and power density over current Class D designs – combines a number of innovations with a Studiomaster patented ‘polyphase’ output stage.
The outcome, says Studiomaster, is sonic performance equivalent to a pure analogue design as well as greater efficiency than a Class D amplifier.
Specific features of the new topology include a modern take on the ‘current dumping’ design of the 1970s. In this Class AD design, the bi-polar output stage is replaced with an ultra-fast switching Class D stage using MOSFET devices. Additionally, the usual parallel operation of the MOSFET devices is replaced by Studiomaster’s patented Polyphase mode, whereby pairs of MOSFETs operate at different times sequentially. This provides the opportunity to overlap the devices when the load is greater or the signal is bigger. The net result is a ‘far higher’ apparent switching speed and a reduction in the required output filtering and switching artefacts.
The topology design also sees Class D circuitry become inactive at very low signal levels, with only the Class A component operating. This means that at small signal levels the inherent sonic limitations of Class D amplification are eliminated, allowing the system to run as it were a high quality, purely analogue device.
Paul Belcher (pictured), head of R&D at Studiomaster, commented: “Innovation has always been at the heart of Studiomaster’s R&D, from the very beginnings of the company and developments like this demonstrate that that is still very much the case. We are already developing new designs that exploit this new amplifier technology across a range of product categories.”
The technical reference document describing the new Studiomaster Class AD Polyphase development can be downloaded at http://www.studiomaster.com/files/ClassADamp_techref.pdf