Class G/H Amp ?

[Kelby9906]

Can someone please explain to me how this amp is different/better/worse than other class A/B or D amps?

http://www.onlinecarstereo.com/CarAudio/p_18815_Clarion_DPX1851.aspx

I've heard good things about Clarion's headunits, but how good are their amps?

And also, whats the skinny on this Phoenix Gold Amp?

http://www.woofersetc.com/p475/X6001--Phoenix-Gold-Xenon-600-Watt-Mono-Amplifier.htm

To my untrained eye both of these look like a good match for an IDQ10V3.D4 sub. Am I right?

[bboyvek]

a g/h amp has the advantages of a d amp plus the sound or an a/b amp, you cant go wrong with the clarion

[rogan]

As I understand it there's a bit of ARC audio in those Clarion amps. The Clarion should work well with the IDQ10v3d4

[OUSHark]

That likely has the same guts as the Arc Audio KS series amps. I have a KS 300.4 and they are execllent amps. A class G/H amp is a hybrid with basically a class D input stage and a class A/B output stage (That's the way I understand it, but I'm not an expert). Basically, you get an amp that's almost as efficient as a class D and much smaller than a class A/B, but the full range sound quality of the class A/B.

Go with the Clarion. Phoenix Gold isn't what it used to be.

[MJ DOOM]

major difference in sq between class a/b amps and d class amps? Im seeing more of full range class d amps.

[IamCatman]

major difference in sq between class a/b amps and d class amps? Im seeing more of full range class d amps.

They can run full range and still suck. Class D amps are awfully noisy which is why they are popular on subs since the noise is not as noticeable as when played in the upper ranges. Also, Class D amps have a very low damping factor which leads to sloppy uncontrolled bass. Now ...most of these kids that think the Class D amps are great are playing rap and hiphop so it really doesn't matter since the bass is sloppy and uncontrolled anyway.

>^..^<

[OUSHark]

Yes, your seeing more full range class D amps out there, but they still suck. I owned an Alpine PDX and it was enough to make me vow I would never run a class D again. I replaced it with the Arc KS400.3 and the difference was amazing.

You're seeing more full range Class D amps out there because they are more efficient, they're small. They do NOT sound better. Oh, and the biggest reason you're seeing more out there is because they are cheaper to build and can be sold at a higher price (i.e. greater profit margin for the mfgr.).

[Kelby9906]

Thanks guys, I get the picture. Ordered the Clarion amp at about 2:00 this morning right after I stumbled into the house after about 6 hours of drunken poker. . .

[rogan]

Thanks guys, I get the picture. Ordered the Clarion amp at about 2:00 this morning right after I stumbled into the house after about 6 hours of drunken poker. . .

Never go drunk internet shopping. The potential for disaster is huge.

[Kelby9906]

Never go drunk internet shopping. The potential for disaster is huge.
haha I'm pretty sure I got the correct amp, but yea you're right about "drunk ordering"

[IamCatman]

Never go drunk internet shopping. The potential for disaster is huge.

Hell ....you should try Ebay while taking Xanax, Morphine and Neurontin. :eek:

>^..^<

[bmwman91]

A class G amplifier is basically a class A/B amplifier with multiple output stages at different supply voltages. Say you have 12V and 18V rails. When the "volume" is not cranked way up, the 12V stage runs. When the output is turned up more, or has a very big transient, the 18V stage will kick in when needed to prevent clipping, then turn off to save some power.

This helps to improve the efficiency (generates less heat, can lead to longer component life/lower cost of ownership). The stuff has gotten big in pro audio applications since those guys have tons of equipment and already spend a lot maintaining it all. Class G is of dubious benefit in applications of less than 300W where the improvement in thermal efficiency does not make as much of a difference (10% improvement in 300W versus 10000W is 30W less, versus 1000W less). However, if it is not done well it will have inferior distortion to A/B units. There is crossover distortion when the high power stage kicks in, which is basically adding more of the same distortion that you get in A/B (versus Class A).

A good primer (the rest of the site kicks ass, too):
http://sound.westhost.com/articles/class-g.htm

Oh, and Class-D is more of a marketing gimmick than anything right now. It CAN be done very well, but I would wager a bet that in all car audio amps it is poop. It is expensive and complicated to make a hi-fi worthy class-D unit. It is very similar to the use of high ISO speeds in pocket-sized digital cameras..total BS. Class D is inherently far more efficient than A/B, allowing the makers to rate amplifiers at ridiculous capacities, but the fidelity suffers.

[DennisCooper]

Hi all

I'm reading up with this to being my 'Audiophile' levels of knowledge back up to speed!

I'm literally DYING to get some Arc Audio amplifiers. I saw them at the SEMA show and was impressed. I want the tiny XXD range as I'm aiming for total stealth installation in my Touring. I'm speaking to Arc audio directly in order to potentially be a UK distributor as well.

Now Audiophile levels of quality in cars is quite hard to achieve in terms of demand by 'most' customers. Many BMW guys only want the 'oem' head unit and nothing else! and the 'usual' pricing levels means a very small proportion will be at this level.

Many go for a mixture of price, brand, power outputs - Classes of electronic amplification and mentioning of capacitors and transistors and other newer technologies isn't really up on their list of product knowledge. The marketing, as already mentioned takes over.

Although I do love my hip hop and high energy dance/club electronica music, I also love the various tracks within these genres that use clear sounding vocals - both male and female and some tracks sounding very smooth in terms of being able to demonstrate very nicely.

With good 'mid fi' (thanks I am Catman!!) solutions/products at a decent pricing level, I aim to look to that market in order to maximise my concepts and solutions. I do however want to have my high end stuff as well!

For the moment I'm using these Class G/H amplifiers http://www.vibeshop.co.uk/category/Amps/Lite_Box_Amplifiers,b.html as they're small, as an interim solution until I can get a hold of the Arc Audio XXD's.


Cheers for now! Dennis! West London UK

[Benny Z]

major difference in sq between class a/b amps and d class amps? Im seeing more of full range class d amps.

it's unfortunate, isn't it?

:(

[HK_M3]

The right switching amplifiers are superior to class a/b designs. Damping factors above 60 are all you need, there is no way to tell the difference after such number. (99% of amps have a damping factor of 100 or better)

On some of these amps I believe you are hearing the sub standard filters and xovers they use on the amp. You can't even hear 1-3% distortion in an amplifier. The speaker (and it's crossover!) introduce the most distortion into the signal path.

Class D amps are no longer "dirty" they are on par with anything else out there. JL Audio's HD amplifiers (Class G) are way more effecient than their own Class D amps.

Check out single cycle control

http://www.powerphysics.com/

A lot of you guys are spitting out info you've heard from a friend or think you hear in a car. I assure you other factors are the case. Do some research, stop listening to the snake oil that that ruins this hobby.

[bmwman91]

it's unfortunate, isn't it?

:(
"Would you like some 128kbps MP3's with that?"



The right switching amplifiers are superior to class a/b designs. Damping factors above 60 are all you need, there is no way to tell the difference after such number. (99% of amps have a damping factor of 100 or better)
From a thermal efficiency standpoint, yes switching amplifiers (I hate it when people call them digital) win every time, hands down. A bad class-D amp will do better than 50% efficiency, which is pretty good in A/B land. I have seen a few true full range, hi-fi grade class D amplifiers. Price-wise, they are pretty competitive with comparable A/B designs.

Switching amplifiers are very complicated to implement well, and I think that they will continue to be used mostly in subwoofer applications for a long time. Doing them right is expensive if you are after full range amplification. I wouldn't go so far as to call RF system design a black art (some EEs I work with do lol), but it takes a lot of experience and iteration to get the design down for each application since physical layout is crucial.

Class-D has become the only way for car amp makers to continue competing in the crazy power number marketing game. Getting outputs of that level with A/B would pose serious thermal/reliability problems. Although A/B is a lot less expensive in terms of components, they probably realized that it was cheaper to go class-D in the long term since it could lead to fewer warranty repairs (and maybe they didn't want to get bad reputations for hot/faulty stuff). In that sense it is superior, but they aren't about to spend the money making a full-range switching amp since their main market wouldn't want to pay $2000 for a 4 channel x 100W amp (or something like that, the price would be heinous to keep margins up).


On some of these amps I believe you are hearing the sub standard filters and xovers they use on the amp. You can't hear 1-3% distortion in an amplifier.
I couldn't agree more. I have been reverse engineering the pre-amp stage on an MB-Quart amp. It uses $0.60 general purpose op-amps (MC4558 & a TL072) that aren't terrible, but certainly leave a lot to be desired. I am going to swap in some OPA2134's which are a good balance between price & performance. An op-amp with GBWP of more than ~10MHz is probably a bad idea in the presence of the switching circuitry. The pots & filters aren't using components with terribly tight tolerances either (which are getting jumped over since an external active XO is being used).

With respect to the distortion...Depending on the nature of the distortion, it could be annoying/fatiguing. Odd-harmonic distortion at the -30~-40dB level might not be directly noticeable, but it can probably lead to listening fatigue after a while. Of course, that is still probably a lot less distortion than the drivers themselves develop so it might not be an issue.


Class D amps are no longer "dirty" they are on par with anything else out there. JL Audio's HD amplifiers (Class G) are way more effecient than their own Class D amps.

Check out single cycle control

http://www.powerphysics.com/
Those look to be on-par with some of the full-range switching amps I have seen. Neato.

Class G is not a switching topology in the same sense as D, so I wouldn't necessarily compare it with class-D. G (more-so H) has the potential to be very efficient. The designers just need to keep the crossover distortion well controlled when the output switches between power rails. I don't think that G really ends up being more efficient than D since it is more of a modified A/B topology. Everything has pro's & con's though, and I bet I couldn't tell the difference in a blind test anyway.


A lot of you guys are spitting out info you've heard from a friend or think you hear in a car. I assure you other factors are the case. Do some research, stop listening to the snake oil that that ruins this hobby.
At the end of the day you are probably right. In a car environment, the noise developed by modern solid-state amplifiers that are tuned reasonably well is probably well below all the stuff coming from the motor & wheels. Audio is super subjective and psychoacoustics are the biggest factor in it all.