importtoys

Have you guys ( Gene ,Percy or anyone ) used or installed any of the digital class amps? I had one that a company gave us to demo but it never made it to the lexus We installed it in a Tahoe since the SC wassnt ready...everything can be load in an SUV!! so then it had to go back and it never got benched or tested in a passenger car
D class and T class i hear are only used for subs because they have have full range 'issues' .....I just wanted an opinion on them other than mine. I dont consider myself an audiophile so im looking for some input

Percy

Now there's a topic that I haven't heard in a while! The first one to use this in a commerical product was Infinity back in '90 or there abouts. Class D switching. The audio isn't converted into anything digital (no digital to analog or analog to digital converters) but rather the output transistors are being pulsed on and off rapidly to promote efficiency whereas the standard amp is running either Class A (full on) or Class AB. In theory (Class D), the output transistors are switched at a high enough rate to avoid harmonics from interfering the audio signal, but that's in THEORY. Haven't tried any so I wouldn't know as to their sound quality. Ken C. Pohlman did a review on this amp (Infinity 40x2, circa 1990) and the only specs that I found lacking was the channel seperation, somewhere around 55db. For comparison, McIntosh's MC4000M, out of the box, would be in the low to mid 90's, which is still the world recordbreaker/benchmark. PPI was doing something in the high 50's...low 60's. BUT, Class D amps do inherently run cooler and are smaller, watt for watt due to their design. But, they are temperature sensitive and they have to be designed correctly to offset this.

I personally haven't seen any Class D amps (or class T for that matter) with very high S/N ratios (over 100) or very high channel seperation numbers. Even the quietest amps in the world (Krell/Levinson/Dynaudio Arbiter) use class A. But the Arbiter does one better in that it uses a highly refined battery (pure DC) source for the ultimate in extremely low noise floor. No AC ripple...no noise from the power supply. Now how many of you knew that Dynaudio made amps? They're over 100k$ and used to test the ESOTAR line of speakers/drivers.

In short, I haven't had the opportunity to audition a class D/T amp extensively so I wouldn't be able to comment on their overall "sound". But, like any other amp, there are good ones and there are bad ones. Kraco vs Mc. Both are Class A / AB but there are worlds of difference between the two!

Percy

LexDriver18

Percy,
In your opinion, what is the best amp for SPL, price not being a factor??

What about the best SPL amp for a good price? Best bang for your buck...

I just wanted to rack your brain and see what an expert like you would put in your ride if you were an SPL guy like myself...

Justin
Platinum 2G GS4

Percy

Justin,

For car audio...no idea. For home audio...Krell Refernce amps. Can pump several THOUSAND watts into each channel at 1/2 an ohm, which is pretty much a dead short. Needs 2 50 amp power supplies to run at full capacity. Very heavy...several hundred pounds each. You'll need 2 if you're running dual subs.

I'm still going for Infinity Class D amps on bang for the buck. From what Brad told me, Xtant isn't too reliable and PPI isn't all that great. RF seems to ride on hype more than anything else. Who else (other than hype companies) would come up with huge acronyms and brag about surface mount components?

For an overkill project, and if you can mod one out, and as someone said (money no object...Ira?) then I would go for the Krell amps. You won't need lowering springs. Believe me!

Percy

LexDriver18

No lowering springs?? GREAT.... I can kill 2 birds with one stone!! LOL

Justin
Platinum 2G GS4

bmm89

Never heard of these...any other info?

Percy

Percy, have you heard about the REAL digital amps from TI that was at the last CES. I'm sure i'm not up to your standards but they sounded sweet, to say the least and i was very very surprised that for speakers they were using some cheapo radio shack speakers. Apparently the unit takes the output from the speakers and re-equalizes, or whatever other magic it does, to compensate for the speakers, so that they essentially sound "perfect."