Class D "digital" amps. Opinions on performance

[BurningSkies]

Honestly, it doesn't support my case, either.

It means they trust you enough to handle the cash box full of ones and fives and organize the bake sale.

That's good in my book.

 

[seamonkey]

That's an understatement of what they do. The two sides of each output are not only each a separate class D circuit, but they are clocked in quadrature so they are interleaved. This doubles the effective switching frequency and makes the reconstruction filter more effective without the attendant problems of making the output devices themselves switch at double the frequency. It's quite clever. I think it was Gerald Stanley who came up with that.

It's also a clever way to implement a grounded-bridge topology. Crown had used grounded-bridge in many of their high-power linear power amps as a way to double the output voltage capability of the output transistors. (BTW, they were still class AB--and the "VZ" models were essentially class H, though implemented in an unusual way.)

This is great info.
Thanks
I should just stick with "PWM amp"

 

[Bob Lee (QSC)]

It means they trust you enough to handle the cash box full of ones and fives and organize the bake sale.

That's good in my book.

Uh, that's the treasurer's job.

 

[BurningSkies]

Uh, that's the treasurer's job.

Oh, that's right. You're the one who takes dictation and orders the coffee and sammiches for meetings.

 

[projectMalamute]

It's not a straw man argument.

A class I amp is a different topology than a class D amp. You have described some of the differences yourself. Whether you feel these differences rise to the level of giving it a different name is immaterial. You are not supreme dude in charge of making those decisions.

An I-Tech works in a different way than any of the numerous class D amps everybody is always going on about around here. The amps big touring companies are using are fundamentally different things than a 1kW class D amp from Guitar Center.

Saying that class D amps, as a general category, sound good because 'big touring companies' are using them is a huge stretch for a whole number of reasons. Not the least of which being that these 'big touring companies' are using totally different amps that work in a different way.

I'm done.

 

[jnewmark]

Oh, that's right. You're the one who takes dictation and orders the coffee and sammiches for meetings.

Cool. Can I get a Class AB on rye, with a side of Class D ?

 

[Bob Lee (QSC)]

A class I amp is still class D. Like I said, there are a lot of different ways you can implement class D.

 

[BurningSkies]

If Class I is an implementation that uses two class D power amps together, does that mean it sounds twice as bad as a 'regular' class D?

 

[wcriley]

A class I amp is still class D. Like I said, there are a lot of different ways you can implement class D.

Aren't there also different "implementations" of class A/B?

 

[projectMalamute]

I-Techs sound great. The aural equivalent of a sledgehammer in my experience.

 

[projectMalamute]

Aren't there also different "implementations" of class A/B?

At least one of them being class H. Bob is in charge of deciding whether stuff gets a new letter or not.

 

[Bob Lee (QSC)]

Aren't there also different "implementations" of class A/B?

Sure, you can do class AB in many ways, too.

Here's an analogy: a lawn mower and a Formula 1 car, and in fact most vehicles with internal combustion engines, use Otto-cycle engines. Yet the many variations and implemantations number in the thousands. Probably tens of thousands, at least.

 

[Bob Lee (QSC)]

At least one of them being class H. Bob is in charge of deciding whether stuff gets a new letter or not.

No, the IEEE is. Take it up with them.

 

[bryanspkr]

Hey what about the possible tradeoffs possibly necessary in these very small heads. So what is the current state of things for what is out there at the moment. I think we can agree that some Class d power amps perform better than some so called conventional designs and vice versa. I can vouch for my Hypex, but that is not an all in one micro head.

 

[wcriley]

I've been trying to research "class I" amplifiers and the only references I can find are from Crown. Does the IEEE recognize class I or is it a proprietary designation?

 

[Bob Lee (QSC)]

Does the IEEE recognize class I or is it a proprietary designation?

It's proprietary.

 

[Chef]

Mod Insert:
ProjectMalamute:

find a way to make your points less accusatory and personal sounding, or we're gonna have a problem.

thanks

 

[wcriley]

It's proprietary.

So then, if I understand correctly, class I isn't "basically" class D, it's technically class D.

/argument

 

[seamonkey]

Maybe the title should be:
"Pulse Width Amplifiers (PWM) opinions on performance"

There isn't any trades offs, science has known for 50 years what humans can hear. It's a science. Power Amplifier today far exceed what humans can hear.

PWM (Pulse Width Modulation) is identical to other PWD designs
non-PWV is identical to other non-PWD designs
PWM is identical to non-PWM designs

Sonically:
PWM (Pulse Width Modulation) is identical to other PWD designs
non-PWV is identical to other non-PWD designs
PWM is identical to non-PWM designs

Bass head manufacturers usually have value added circuitry and features that sonically manipulate the output heard at the drivers.

More energy efficient designs need less space and can fit into smaller places.

 

[Bob Lee (QSC)]

So then, if I understand correctly, class I isn't "basically" class D, it's technically class D.

True.