CaysE

I have two subs, each with their own enclosure in a single box, and have been looking at class-D amps to power them. I haven't looked a lot into what "Class-D" really is, but from what I can tell, they give better bass response/powering, etc. If anyone wants to fill me in on this, feel free.

My question is, are there any 2-channel Class-D amps? I would like to power each sub on their own channel, and all I've seen so far is mono.

HanSoloWS6

I'm pretty positive all Class D are mono amps. And you got the basic's of Class D amps. They are usually stable for ohm loads of 2 or lower, some even for .25. If there is such an animal as a 2ch. Class D, you might find them produced by full on competition audio makers. Maybe an MMATS or something, but I doubt it. Just have to do a lot of searching, lol.

Jim85IROC

iTrader: (2)

no, there aren't any 2 channel class d amps. There is no need. The frequency response of a class D amp is too narrow to run anything but subs, and since almost all music has mono low frequency content, you're always better off to parallel wire the subs to feed them a mono signal and to get more power out of the amp.

separate box or not, there's no need to power the subs separately.

CAMp3RO

i thought we had the "stereo vs mono sub" debate already

Jim85IROC

iTrader: (2)

We may have. The dumber the conversation, the faster I tend to forget it.

CaysE

Yeah, I started the war. But dumb or not, that's what I'm doing, and is not the topic of this thread. Thanks for the info... guess I'll run 2 mono amps then.

CAMp3RO

well then, best of luck getting everything matched up. hope you got some gear to set up the two amp gains and matching whatever else the subs need. i prefer the KISS method....

Jim85IROC

iTrader: (2)

when you have subs in separate enclosures, getting the two gains 100% perfect isn't critical. It is if they share an enclosure, but as long as they are separate, other than sacrificing a dB or 2, you don't run into any problems with slightly mis-matched levels.

Flash84Z28

There may be an amp with two class D amps in a single chassis. BTW, a .25 ohm is a dead short. I think Orion made a 1/2 ohm stable amp a long time ago. Everyone else is 2, sometimes 1.

CAMp3RO

aww jim, why cant you let me pick on him. jk

FyreLance

Why?

HanSoloWS6

I forget who made it, but someone had an amp listed as 1/4 ohm stable. I found it strange myself. But there was one at a shop around here and they had it working overtime to show it will stay at a constant temp no matter how long it was working. Heck, maybe I'm wrong, I could be, lol, it's just something I saw at a local shop.

Flash84Z28

Most likley the person who said this was playing a joke on someone. I love going into Best Buy or a similar store and asking if there amps are all a quarter ohm stable or if they have flux capacitors....(Back the the Future).

HanSoloWS6

haha Best Buy is a joke anyway. Seems like all the "high end" stuff they sell is the equipment that didn't make it through QC the frist time around. Too many people I know seem to have problems. Also, I bought a pair of 12's years ago from them, within a week, properly powered and in the right enclosure, the wires from the terminals going to the coil fried and the dust cap was junk. These were the old Blau black and white ones though. But I have had Pyramid stuff last longer lol.

FyreLance

Pyramid..blah

Jim85IROC

iTrader: (2)

I've seen liquid cooled Orion HCCA amps push a .25 ohm load. When those amps first came out it wasn't uncommon to see 1 amp pushing a whole wall of subs.

mcss383

If you want a 2-channel 'class D' look for class T. Its the same thing as a class D but has Tripath's chip to allow full-range freq response. There are a whole lot of class T's out there (Arc audio has some, Hifonics has some as well as others).

There is a Class D now available that will work from 20-20kHz, the new Xtant 1.1i, but its only 100rms and not meant for subs (and is mono as well).

Jim85IROC

iTrader: (2)

I wasn't aware that there were any full range class D amps available yet. Last I knew the fastest switching power supplies they could furnish switched at about 500hz.

Jim85IROC

iTrader: (2)

Interresting. I've been doing a little reading on the tripath chip. Apparently they're using a feedback circuit to reduce distortion at high frequencies. That makes absolutely no sense to me at all, so I guess I have to keep reading.

The more reading I do, the more suspicious I get. I found that a couple years ago Alpine had a Class T amp with the Tripath chip. If that was the case, why isn't there all kinds of hype and more information 3 years later?

I need to do some homework on this.

Jim85IROC

iTrader: (2)

Ahh... Jim's brain is getting bigger.

Apparently the switching of the power supplies is noisy. The fact that class D amps only operate at low frequencies seems to be more an issue of noise than switching speed, and it's easier to get the noise out if they filter the high frequencies.

So... the Tripath chip is using a feedback system (and presumably a ton of DSP) to reduce this high frequency noise.

Apparently you can also design a class D amplifier to work in a full range setup by using higher frequency switching, which moves the noise beyond the audible spectrum, but also lowers efficiency, which is the major calling of the class d amp in the first place.

In any case, this is pretty interresting. My major question right now is why aren't there more of these things out there?

CAMp3RO

my only thinking is that the technology is still very young.... early adopters stage. companies must also pay money to use the tripath chip and name in their amps. however, from everything i've read about the Blaupunkt class t amps, they're great. very little complaints about them. which is surprising seeing how many people dont like that company and its products. i wouldnt mind getting a couple of them because they're perfect for our cars; tiny and dont get hot

Justins86bird

PG Tantrum 1200.1 is also a class T amp.

9177

http://www.clarion.com/amps/ampsfm.htm heres one. I think all af blaupunkt amps are class t

Jim85IROC

iTrader: (2)

All that class "T" indicates is that it's got the tripath chip. There are also full range class D amps, and there are class "x" amps, which use technology similar to what Tripath has come up with.

It's too bad they need to mess with the "class T" and "class X" crap though. The world got along just fine going in consecutive order as new amp technologies emerged (class a, class b, class a/b, class c, and then class d). Unfortunately, the "class T" and "class X" stuff is a result of somebody's marketing department, not their engineering department. These amps are still technically class D amps.

EDIT: Just to clarify, I'm not criticizing the technology of these amps... just their naming classifications.

CAMp3RO

well, T i can understand, becuase a company wants to be known for something . but i was always told "X" was strictly a marketing term. they're just class d with a marketing department's brilliant name. but, i could be wrong. ya know, it happens sometimes. haha

mcss383

nope, your right. Class 'X' is yet another engineering feat thought up by marketing. hehe