In the past using a class A amplification at high power levels for its low thd was a bit of a joke because every other component in the amplification stage was so noisy or distortion prone, particularly the highly reactive loudspeakers. I have not kept up with the technology of output devices. I know significant progress has been made. I would like to know what hardware the author would reccommend their Amplifier be used to drive? What the thd of the complete amplifier chain would have. Also given the logarithmic roll off of human hearing, whether we could distiguish between his class A of a good quality A B output design?

Obviously you'd need a quality loudspeaker to fully appreciate the quality of this amplifier. Moreover, driving it from a single-ended, rather than the intended balanced source would negate many of the benefits. I can't really say how it compares to a run-of-the-mill class-AB, as theirs millions of them out there, with specs ranging from atrocious to mediocre for the majority of commercial designs by popular brands.

Best regards,

I would like to try this amp. Where can I buy the kit if I decide. Is it possible to add more transistor in parallel to get more power? Let me know.

Thanks,

Freddie V

Freddie,

Bare PCBs are available, as mentioned in the last page, contact me for details. Using more output devices would allow you to raise the idle current and hence achieve higher output power, the penalty however is you'll need an even larger heatsink.

Best regards,