Thread: AES Show Report
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geoff geoff is offline
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On 5/01/2015 8:21 a.m., Scott Dorsey wrote:
Nate Najar wrote:
What is it about class d amps you don't like? I have some experience on th=
e instrument amplifier side and I've been finding disillusionment in them, =
but I cannot say if that is a function of the class d amp itself, or the de=
sign of the entire package. But I had the new PMC two.two near fields here=
for a few weeks and they are powered by the newer hyped class d amps and t=
hey were impressive all around.


It's just an awful lot of stuff in that box that has to be designed just
right in order to get the kind of linearity that is easy to achieve with
a simple Class B design. The PWM controller turns out not be as simple
as people had thought... any transients at the switching stage cause some
weird artifacts.... even the integrator is possible to screw up, and just
throwing overall feedback across everything and hoping it linearizes
everything doesn't work any better than it did in the Dynaco ST120.

I'm not saying the Class D design doesn't have use, but unless you are
desperately concerned about weight and efficiency, I don't see a great
point in it. And, I'm writing for an audience of people who (presumably)
consider sound quality of paramount concern.

That said, I am getting ready to load a rack of four Urei studio monitor
amps into a truck for a film festival gig in Boston, and I am not looking
forward to the experience. A similarly-powered Class D amp would fit in
my pocket... but really the Ureis sound good...
--scott



How about a compromise - Lab Gruppen's 'essentially' Class AB power amps
powered from a Class D amp configured as a tracking power supply ?

Though never had a problem with straight D amps since a few years ago.
Earlier ones often had weird swooshing background noise if you stuck
your ear right up to speaker ....


geoff