On Tue, 9 Jan 2007 09:20:30 -0500, "Jimmie D"
wrote in
:


"JSF" wrote in message
...
OOO crap did any one notice the class d amp WAS running off the 120V line
input NO Isolation to the Finel D amp section to the speakers, WOW
SHOCKING.

"james" wrote in message
...
On Thu, 04 Jan 2007 18:17:51 -0800, Frank Gilliland
wrote:

+++No kidding. My favorite hobby has nothing to do with electronics; I
+++rebuild & restore old Coleman lanterns. I would gladly trade any of
+++the crusty old CB's from my pile for a crusty old Coleman lantern.
**************

My favorite hobby is astronomy. There bigger is definitely better.


james



Not to uncommon for a design that WILL work of of line voltage to not show a
transformer even though it should have one. This may be in the verbal
description of the AMP. Also any High Power amp may have a couple of hundred
volts DC on the speaker terminals if there is componet failure. There should
be circuitry to prevent this.whether it is line isolated or not. Typically
the protection circuit CROWBARS the power supply blowing the fuse(s). Again
it is not uncommon for something like this to not be included in the draft
copy of an amp design.


You're right, and I think I remember saying that it was a prototype.
The production version was a 2-channel unit that included a better
front-end with clipping indicator, a triac power switch (easier on the
power lines), a DC offset protection circuit (no crowbar), and thermal
breakers on the sinks. It was conservatively rated at 1000 watts RMS
continuous into 2 ohms in bridge mode. It could do 2000 watts but the
filters would get too hot because of the low carrier frequency, which
was the primary limitation of MOSFET technology at the time. Nowdays
they make MOSFETs with rise times in the sub nS range which made this
amp obsolete very quickly.