Class D vs. class a/b Amplifiers

[zako 10+ year member]

i think amps sound different because of slew rate, not just THD. a well made Class D will be just fine.

It's interesting that almost no one ever mentions the slew rate. Perhaps it's not very important? Only once I heard someone making the implication that high slew rate = more dynamic sound.

 

[keep_hope_alive Premium Member]

It's interesting that almost no one ever mentions the slew rate. Perhaps it's not very important? Only once I heard someone making the implication that high slew rate = more dynamic sound.

slew rate is very important. it's neglected because few people in car audio even know what it means, let alone how it applies. The cost difference between high and low slew rate op amps is staggering. and yes, it has an effect on dynamics if the devices simply cant increase voltage fast enough. it can also present itself as distortion. THD is also mostly mis-understood since it's a moving target that changes with impedance, power output, and even temperature. I think amps should have graphs, not single number ratings for THD vs Power, Efficiency vs Power, Impulse Response, and Damping Factor vs Power... and one graph of each for several impedance loads.

 

[SPLaudio 5,000+ posts]

class a/b !!!

 

[n2audio 5,000+ posts]

I haven't studied the topic at all, but I ran across these in a quick search: Significance of slew rate - CARSOUND.COM Forum

http://forums.audioholics.com/forums/amps-pre-pros-receivers/7278-de-mystifying-slew-rate-amplifiers.html

 

[gunz4me2 10+ year member]

I have NO problems with my Class A/B amps ...

Why don't you tell everyone how many batteries you have in your truck and what your RMS rated power is when making such an assertion?

 

[cablguy184 10+ year member]

Why don't you tell everyone how many batteries you have in your truck and what your RMS rated power is when making such an assertion?

absolutely ...

2 Walmart batteries under the hood (recommended specs for my truck) on a GM 140 amp alternator (bought at AutoZone) ...

with all 1 awg/ 0 g welding cable ...

Front stage ... 2 Linear Power 2150s ... 150 watts per channel ...

sub stage ... 1 Linear Power 2250 ... 250 watts per channel, but running 8 ohms mono at the moment. Not sure what the actual wattage output is, but its VERY aggressive !!!

 

[audiobaun 5,000+ posts]

So theres really no difference between the twoo? And id be getting the Alpine MRX-F65. Is that a good amp? I mean i dont think you can go wrong with alpine but i just want to make sureeee.

Thats a nicely made amp with quite a bit of power.It should be great on any aftermarket speaker you choose to power up.Alpine has always been a well made amp,since the late 80s/early 90s with the 35 series Duo-b, which are still some of the best they produced,for SQ,and power as well.Nice choice..I wouldnt hesitate to run that amp by any means

 

[zako 10+ year member]

Here is an interesting take on Class A/B vs Class D from the founder and former lead engineer of Image Dynamics. (hint: it's probably not what you think...)

Start reading at the post 32 and below:

Eric Stevens new company? - Page 2 - DIYMA Car Audio Forum

 

[audiobaun 5,000+ posts]

I have ran a/b amps since 88, and recently began to run d amps in one system, and a mixture of d on my subs,and a/b on front stage.i myself really cant tell a whole lot of real difference other than using an old zed made amp,which seems to have a richer deeper,cleaner sound,but they still sound very nice, my only concern of class d amps is,are they like the new digital tvs?being digital,do they only last a certain amount of working hours,then need replacement compared to a/b amps, that i have used for 15+yrs,without any issues?

 

[n2audio 5,000+ posts]

If you buy a good quality amp and don't abuse it -- it's going to last.

If you buy a cheapo, and/or abuse a good amp it's probably not going to be around for long.

I don't think the class of the amp has much - if anything - to do with that.

My '00-01' Lanzar (Zed) class D is running fine.