"Eeyore" wrote in
message
Scott Dorsey wrote:

tony sayer wrote:

Anyone ever made a good commercially viable class D
amp?...

Everyone and his brother has. A huge number of portable
devices, from iPods to laptops, are using class D stages
because of the low power consumption. You're also
starting to see them inside a lot of powered speakers.
Tripath and TI are some of the popular manufacturers.

I keep hearing good things about Hypex btw.

The big problem sonic with switchmode amps is excessive output impedance
within the audio range.

Hypex gets points for putting output impedance at 20 KHz on their spec
sheets, but I notice big "TBD" entries on the spec sheet for their
latest-greatest:

http://www.hypex.nl/newweb/docs/UcD700_datasheet.pdf

Doesn't seem to stop them from trying to sell them, though!

http://www.hypex.nl/classd/classd.pdf

gives about 0.1 ohm at 20 KHz, which corresponds to a damping factor of
about 80. This compares to 0.4 or so ohms for a typical traditional power
amp with output choke, so the Hypex is very good.