• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

My New SE-OTL Amplifier

Hi again Tony. I don't think you'll need to dissipate anything like 80Watts.

In the 13E1 build, I tested the current sinks with them bolted to substantial heatsinks and they only got warm so to save space with the final build I dispensed with the heatsinks and bolted the MosFETs to the chassis top plate (they're right at the front, extreme left and right with a few slots either side to increase the surface area and air flow). The chassis top plate gets warm but I can easily keep my fingers on it where the MosFETs are mounted.

Anyway, this coming weekend I plan to finish the 6C33C SE-OTL build so I'll measure between the cathode and ground and let you know. B+ on my 6C33C is 130V and I'll set the current sinks to around 470mA. Incidentally, the 6C33C project will be using Maida regulators throughout, one per 6C33C and another for the input/driver stages.