Variant of the Aleph 4, a true 100W Class-A amplifier

Built on a budget of less than £200 (mostly E-Bay). It generates some 400W of heat so the heatsinking is massive as are the power supplies. It uses 24 x IRFP244 MOS-FETs which are closely matched into groups of 6. This is the most exhaustive part of the build. Other than that the design is incredibly simple. PCBs are available from www.kk-pcb.com, although my article at diyAudio.com details the process and patterns that I used for my own build.

In the guise that you see in the photo, this amplifier runs at an internal temperature of 45 degrees C on a warm British Summer day, which is well below the 70-80 degrees that Nelson himself allows for his commercial products. The sound quality is simply STUNNING. I’m running an Arcam CD36 / Pumpkin-Shuntky Pre-amp / Passive Attenuator / B&W DM633 with Chord Chorus Silver Interconnects. The bass slam is accurate and endless, the sound stage perfect and the midrange just sweet as a nut. This replaced my A700, itself a clone of a Mark Levinson design, and absolutely knocks the ML into the ground.

The full project build can be seen at http://www.diyaudio.com/forums/pass-labs/172276-aleph-4-strickly-diy-project-build.html

Andy Freestone