''if you love your sub, dont use a class D amplifier''

 

Anonymous
 
I've read this statement on this forum recently, cant remember who said it tho.

But is this true, i mean are class d amps any ''bad'' for your subs.

Class AB draws more current thats why i'm considering class d, but after reading this i'm concerned.

Can anyone shed some light on this matter.
 

Bronze Member
Username: Zacdavis

Beloit, Wi

Post Number: 24
Registered: Dec-03
thats bull, nothin wrong with class d.
 

Silver Member
Username: Solacedagony

New Jersey US

Post Number: 285
Registered: Oct-04
Basically what the person was saying was that a class AB is going to be slightly clearer and cleaner than a class D. I would be surprised if you could even hear the difference between the two, but regardless, that's why that comment was made.
 

Gold Member
Username: Invain

Michigan United States

Post Number: 1287
Registered: Aug-04
Well, Isaac and other people do swear that you can hear the difference, and once you have a high quality AB amp running your sub, you will never go back. I'm gonna be getting an AB Orion pretty soon, so once I have it I'll tell you guys if it really does sound that much better. I don't doubt it though. The only reason people use class D is because of the higher efficiency. Class D's are usually onle Mono block amps, which are used to power subs. You'd never use a class D amp to power your component speakers.
 

Gold Member
Username: James1115

Wilton, Ct

Post Number: 1550
Registered: Dec-04
class D amps are fine,cheap,and very efficiant. The big difference is a broader frequency range and less distortion. Now I know distortion below 80htz is almost impossable to hear anyways when it comes down to the difference between .08 and .1 but class a/b amps will in fact produce notes that class d's will not and will sound better at that. if you are a regular Joe who is just getting into car audio a class D will work great for you there is nothing wrong with them at all they are SUB amps and that is all but if you want to get into high fidelity sound then class a/b will make all the world of difference. once you have a class d and move up to a a/b you will hear the difference trust me.
 

Silver Member
Username: Solacedagony

New Jersey US

Post Number: 286
Registered: Oct-04
Yea I was sort of referring to an average person as opposed to a audiophile. The difference between a class D Lanzar amp and a Class AB Tru Tech amp would be immense, I'm sure.
 

Gold Member
Username: James1115

Wilton, Ct

Post Number: 1561
Registered: Dec-04
ohhh yeah
 

Bronze Member
Username: Miso

Slovakia

Post Number: 34
Registered: Feb-05
i think that only reason why d-class amps got into the caraudio is because of their lower power requirements(less amps needed).they are only good for subwoofers,no components,as joe stated.they were first introduced to the home audio few years ago,but sound quality was poor,so they never made it to the industry(except powered subwoofers).ABconfiguration is just better sounding,altough less efficient then d-class.(That little extra heat,and bigger alternator's not gonna hurt)go with AB you won't be dissapointed
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 3398
Registered: May-04
"Now I know distortion below 80htz is almost impossable to hear anyways when it comes down to the difference between .08 and .1 but class a/b amps will in fact produce notes that class d's will not and will sound better at that."

The JL Audio W7 was praised because it's distortion levels are around 11% at high volumes. The fact of the matter is that speakers produce multiple times more distortion than an amplifier will. If you're comparing a Class AB amp with a GOOD Class D amp, you won't hear any difference at all until the amplifiers begin clipping. Class D amps are linear within their frequency range and the distortion levels aren't that bad anymore. The Zapco C2k-9.0D is a full range Class D amplifier and performs very well. The damping of a Class AB amp is better, but it's been proven that once you surpass a damping factor of 50, it has no additional effect on the delay time of speakers or in actual sound quality. Damping does hint at transistor quality though, THAT is why it is an important spec. Amplifiers shouldn't have a "sound", at any volume below clipping, NOONE can tell a difference between amplifiers, if you can win the Richard Clark challenge, then by all means go ahead and try to prove me wrong. And yes, that includes crappy Sony Xplod amps and such, Richard Clark allows you to use any amp you want, including Class D, A, AB, and Tube amps. I'm not saying Class D amps are better by any means, given the choice, I too would run AB amps, but that doesn't mean you should overlook Class D amps for a system. There are PLENTY of competitors using Class D amps in their cars, and have won competitions even when running Class D for full range.
 

Gold Member
Username: Invain

Michigan United States

Post Number: 1304
Registered: Aug-04
Jonatha, how come some people swear that AB amps sound better than D amps then? Isaac always tells people that once you change from D to an AB you'll never want to go back.
 

Gold Member
Username: James1115

Wilton, Ct

Post Number: 1586
Registered: Dec-04
So Jon your gonna tell me that if I were to hear my system with my PPI a600 running my sub and then you were to swap a 600 watt sony in there I wouldnt be able to tell the difference? man I am a firm believer in pretty much everything you have ever said on here but I think that is nonsense! maybe I am not understanding what you said could you elaborate please:-)
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 3400
Registered: May-04
They're better on paper. The main thing people notice between amplifiers is subtle differences in power, but when you look at a spec sheet for an amplifier and see the amp that "sounds better" has lower distortion, you'll attribute it to that. If you compared 4 different 150x2 amps, all 4 would in reality produce 4 different power levels. Different amplifier topologies don't make any difference in the sound of an amplifier below clipping levels, your focus should be to buy an amplifier with the best build quality you can get your hands on. McIntosh Labs had a home audio amp years ago with 10% (not a typo) THD at rated power, and it was one of the top amps in the world. Typically, amps with less distortion, higher damping, and overall better specs are built better than amps that "get the job done". They'll have a better power supply that can handle clipping better. The only difference you'll hear between two amplifiers is at clipping levels, that's why you see all the tube vs. transistor posts out there, but when all is made equal in a double blind test, the naysayers can never tell a difference between the two of them. Tube amps have a higher THD than AB amplifiers, but they are even ordered harmonics and they clip softer than a transistor and handle overloads better, that's why tubes are defined as more musical and mellow, but only when clipping.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 3401
Registered: May-04
"So Jon your gonna tell me that if I were to hear my system with my PPI a600 running my sub and then you were to swap a 600 watt sony in there I wouldnt be able to tell the difference?"

Yep, that's what I'm saying. If distortion levels were below clipping and power levels were equal, you would notice absolutely no difference in the sound quality of the amplifiers. Remember that Sonys are overrated, to put out the same amount of power as that PPI amp, it would probably have to be a "1200 watt!" Sony :-)
 

Gold Member
Username: James1115

Wilton, Ct

Post Number: 1591
Registered: Dec-04
I hear what your sayin its just hard to believe it ya know. When you say if distortion levels were below clipping, not all distortion levels are below clipping right? their has to be a catch here. So if this were the case why doesnt everyone buy the cheapest amp out there? say a 1200 watts sony if it will sound the same? I mean put all reliability issues aside.
 

Gold Member
Username: Invain

Michigan United States

Post Number: 1309
Registered: Aug-04
Yeah, I'm kinda confused too...
 

Gold Member
Username: James1115

Wilton, Ct

Post Number: 1594
Registered: Dec-04
I mean I believe you jon about this all its just there has to be some sort of catch
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 3403
Registered: May-04
Security reasons. Clipping happens more often than you think, which is why competitors overpower drivers so that the power supplies are strained less. If you set your gain correctly according to a scope, you still aren't assured that you won't drive the amp into clipping every once in a while. I believe in Clarks test, they are kept below 1%, which most any amplifier on the market will provide. Definately not unreasonable. There is no catch really. Reliability is a broad term, just because an amplifier doesn't break down, doesn't mean that it will handle swinging impedance curves well, or provide optimal damping at the frequencies needed, etc. There are a lot of factors to consider in an amp, but the problem is that it can not be decided upon with your typical amplifier spec sheet, it is attained through full testing of the amplifier through it's frequency range to evaluate the overall performance. Different amplifiers perform better with different speakers, for example, Martin Logan recommends tube amps for their electrostatic panels, it's not because of the sound quality, it is because tube amps typically handle impedance swings better than transistor amps. It's about the load you intend to run, matching the horse to the course.
 

Gold Member
Username: James1115

Wilton, Ct

Post Number: 1597
Registered: Dec-04
you are making me want to go get a sony 1200 watt amp for the hell of it now to hear if it sounds the same to my ear
 

Gold Member
Username: James1115

Wilton, Ct

Post Number: 1599
Registered: Dec-04
also Jonathan one more ? my PPI has a input sesitivity of .2-2.5v, now my head unit puts out 4volts how should I gain this amp properly?
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 3406
Registered: May-04
Ideally you'd use either a voltmeter or a scope, if not than set it to the lowest setting, then turn it up until you hear audible distortion, then back down until it stops. Typically head unit preouts are rated for max output and amp inputs are rated in RMS, so you'll be close to optimum with the gain set to minimum.
 

Gold Member
Username: James1115

Wilton, Ct

Post Number: 1601
Registered: Dec-04
all the way down? or up a little? and the problem is this damn sub will not distort so I have a feeling if I went that way it would be up all the way. I have it set at about half right now or a tad under that is the way I have had it set for the last 3 years but if it is wrong I would like to correct it. When I set it I wsa able to hear distortion in the subs I was using at that time so I figure its good where it is set right? thanks man
 

Bronze Member
Username: Colinjay18

Houston, Tx Usa

Post Number: 29
Registered: Jan-05
can you guys tell me if its ok to use a capacitor with a class d amp? this guy at a local shop today said not to use them together.
 

Gold Member
Username: James1115

Wilton, Ct

Post Number: 1606
Registered: Dec-04
no that is not true a cap has nothing to do with the circuitry of the amp it has to do with relieveing pressure off of your electrical system.
 

Bronze Member
Username: Kojak28

Augusta, GA USA

Post Number: 50
Registered: Feb-05
Hey James, I am kinda new here , but I tend to follow your threads and advice pretty consistently. I read on sounddomain how to adjust your amp. I don't wanna step on anybody's toes here, tho. I am computer stupid when it comes to setting an auto URL, so MAYBE I could just relay it to you. You need a DMM. Set it to a/c voltage. disconect your sub. Start the car. Set your gains LOW(not all the way) tune it to about 60 HZ. Turnn the HU to about 3/4 throttle, measure the speaker outputs, adjust the amp until yhe DMM reads 24.5 volts. This is the optimum amplifier setting. DO NOT exceed this setting. Or so this supposed electrical "genius" stated. Kojak
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 3414
Registered: May-04
24V only applies to that specific amplifier, not all amplifiers. What you would do is determine the voltage that an amp would need to produce it's rated power, the equation is P=V^2/R, where P is power (in watts), V^2 is voltage squared, and R is resistance (in ohms). So if you had an amp that was rated at 100x2 into a 4 ohm load, you'd have 100=V^2/4, which would necessitate a 20 volt output on that single channel.
 

Bronze Member
Username: Kojak28

Augusta, GA USA

Post Number: 53
Registered: Feb-05
I phucked up guys! When I printed out the farkin' page, I missed the part about FOR INSTANCE IF YOU HAD A 150WRMS AMP W/ A 4 OHM LOAD!! I promise I'll open BOTH eyes B4 I offer some advice on a technical issue like this. GGGGRRRRRRR#$&#* frick and frack,sumbich, gol'dang it!! Sorry 'bout that James. Listen to Jonathan-he seems quite technically inclined.More so than me.
 

Bronze Member
Username: Kojak28

Augusta, GA USA

Post Number: 54
Registered: Feb-05
You gotta take the # of watts rms, get the sq root of that # then adjust your amp to get that # of volts.lol
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