A Modular Hybrid Amp System

Tubes or transistors? Whatever your prejudices, this article may make you change your mind about how you view hybrid designs. audioXpress featured this modular hybrid amplifier project in February 2001, which was referenced multiple times by other authors in many subsequent projects. The project features a shunted regulated push-pull (SRPP) stage design, using the ECC82/12AU7 tube combination, followed by a power stage, using two to eight complementary power MOSFETs in parallel.

Simon Brown rethinks what he needs as the amp that will be the centerpiece in his own audio system and perfects a previous design with a true hybrid design. As he writes, "This amp is a “hybrid” in many ways. There is the obvious way in which it uses both valves and MOSFETs. But it’s also a hybrid in its use of enriched Class A/B, which means it is running Class A up to a few watts. This is deliberate." Read the complete project now. This article was originally published in audioXpress, March 2007.