AES Show Report

[Scott Dorsey]

It's up!
http://positive-feedback.com/Issue77/aes14.htm
http://positive-feedback.com/Issue77/aes14_awards.htm

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Nate Najar]

On Saturday, January 3, 2015 5:21:06 PM UTC-5, Scott Dorsey wrote:
> It's up!
> http://positive-feedback.com/Issue77/aes14.htm
> http://positive-feedback.com/Issue77/aes14_awards.htm
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

scott that was terrific thanks.

What is it about class d amps you don't like? I have some experience on the 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 design 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 they were impressive all around.

[Scott Dorsey]

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

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Don Pearce[_3_]]

On 4 Jan 2015 14:21:31 -0500, (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

Class D amps are really good in the use they seem to have fallen into
most readily - sub woofer amps. It is the high frequencies they seem
to have trouble with, mainly.

d

[Les Cargill[_4_]]

(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.
>

I don't know how much is fashion or simply guys getting older and
weight being more of a concern, but on the bass group, the
Markbass and other lightweight stuff gets plenty of respect.

I've heard one or two, and they sounded okay. But I don't think
they quite held up as well as my bottom-dollar Class AB rig
does. This was with other people playing through them, and I
can't really evaluate a bass amp unless I'm playing.

But that's also for bass amps.

IMO, the probable reason for Class D in all the MI stores probably
comes down to shipping weight.

> 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
>

Wheels and ramps good.

--
Les Cargill

[geoff]

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

[Gary Eickmeier]

Scott Dorsey wrote:
> It's up!
> http://positive-feedback.com/Issue77/aes14.htm
> http://positive-feedback.com/Issue77/aes14_awards.htm

So Scott - can you tell us who was the panel hog at the worst panel? And
linik us to a picture of Charlene? Just sayin...

Gary Eickmeier