Andy Evans wrote:

Any views on the range of Tripath eval boards? Sound quality? Mods? For
reference see Profusion website. http://www.profusionplc.com/product-frame.htm

I did try one, several years back. One of the high voltage high power hybrids that
was one of their earlier efforts.

Didn't like the way that the output 'goes fuzzy' on a scope at any level above
about 1/4 power. The eval board also didn't like being run like a PA amp with
various components getting rather warm.

Final killer was the hybrid's inability to provide enough gate drive to cope with
fets suitable for efficient driving of 2 ohm loads and the derating of the supply
voltage needed to cope with LF charge pump issues.

I plan taking another look sometime soon simply using their PWM processor and I'll
tack some IR gate drivers after it, that'll solve all the supply voltage and gate
drive issues.

As also noted, it's tricky with any PWM design to get totally flat inband response
from the output filter with various load impedances.


Graham