Advantages of Class G (Friedman) or H amps over Class A, B, AB (Pedal baby), or D (SD 170, etc)?

JRod4928

Power User
I'm researching power amps and found that there are very few Class G or H power amp offerings. The theory is they're inefficient, so they have high wattage. I suppose the added cost to generate high wattage and size to dissipate heat is why they're less common.

However the Friedman ASC/ASM uses a Class G power amp, so they must have decided there was an advantage to this design.....

I'd like to know what the advantage is of a Class G or H amp is in comparison to A, B, AB or D.

I'm loosely considering this Class H (very very similar to Friedman) in my 2x12 cab, hoping it would be less harsh than Class D. https://www.ebay.com/itm/ACT-1515X-...-/232880366758?_trksid=p2349624.m46890.l49286
 
I went with class H. Lighter than a class A/B because it uses a stepping transformer vs a toroidal transformer. I decided against class D because high frequency performance can be an issue depending on the design and filter quality.
A class G should be on par with class H. If weight isn't an issue I'd choose class A/B. Most audiophiles will choose class A or A/B. However a class A at 540 watts will be the size of an oven. Lol.
Here is a great article that explains the classes and the pros/cons of each.

https://www.audioholics.com/audio-amplifier/amplifier-classes

I was looking at a similar amp doing my celestion build but I need the 110v model which is way more expensive.
Do you really need 1000watts?
Check this one out. It's half the price at 600watts.
https://www.parts-express.com/ACT-1...O_tpOYUweh06LqpPCx9WYddHyzmdTJIBoCGGwQAvD_BwE
 
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I have the Headrush 108's and the Friedman ASC-12. The 108's can definitely dispel any myths that class D doesn't reproduce high-end. They do it in spades (maybe a little too much). The Friedman is super smooth but I attribute that to it's built-in EQ curve. Any of these amps can sound different depending on the preset EQ. I will say the ASC is heavy as sin but that is not just the amp but the thick plywood and sizeable woofer and tweeter magnets.
 
I have the Headrush 108's and the Friedman ASC-12. The 108's can definitely dispel any myths that class D doesn't reproduce high-end. They do it in spades (maybe a little too much). The Friedman is super smooth but I attribute that to it's built-in EQ curve. Any of these amps can sound different depending on the preset EQ. I will say the ASC is heavy as sin but that is not just the amp but the thick plywood and sizeable woofer and tweeter magnets.
Dave Friedman knows his sh!t. I figure if he's not using class D it's for good reason. My Headrush FRFR12s are what steered me away from class D. They can be pretty harsh at high volumes. Plastic cabs just aren't going to get the desired resonance like a quality built birch box either. Don't get me wrong the headrush sound good for what they are and the price. They just left me wanting more of that amp feel. I'm super happy with the diy f12-x200s tho. The Friedman's would be my off the shelf pick.
 
I have the Headrush 108's and the Friedman ASC-12. The 108's can definitely dispel any myths that class D doesn't reproduce high-end. They do it in spades (maybe a little too much). The Friedman is super smooth but I attribute that to it's built-in EQ curve. Any of these amps can sound different depending on the preset EQ. I will say the ASC is heavy as sin but that is not just the amp but the thick plywood and sizeable woofer and tweeter magnets.

This makes me wonder if you're experiencing the same thing I have. Class D always seems to be brighter or harsher, if you want to use that word. It's not that it doesn't reproduce it, it's that it doesn't reproduce high frequencies accurately and in a smooth manner because (my basic understanding is...) Class D uses binary to reproduce sound waves. It's easier to reproduce a low frequency with binary, but higher frequencies require faster processing to accurately reproduce them, so instead of getting a smooth high frequency response, you get a boxy harsh sounding response. At least that's been my experience, and has been backed up by my research of how Class D works......

I have a rudimentary analogy in my head regarding stacking bricks to reproduce a sine wave shape - one with a wave length of 5 feet, another with wave of 100 ft. The 100 ft would be much smoother, whereas the 5 ft would appear boxy due to the size of the bricks relative to the wave length. That's why Class D struggles with high frequencies. They can't change the wave length, but they can change the brick size (faster processing) as tech advances.

Good news is Class D technology is advancing and improving their ability to accurately amplify these high frequencies. However, the bad news for me is those are out of my price range.... The headrush seems like a budget solution to me, but perhaps I'm wrong.
 
I was looking at a similar amp doing my celestion build but I need the 110v model which is way more expensive.
Do you really need 1000watts?
Check this one out. It's half the price at 600watts.
https://www.parts-express.com/ACT-1...O_tpOYUweh06LqpPCx9WYddHyzmdTJIBoCGGwQAvD_BwE

600 would be plenty. It appears those are sold out (I though B52 got out of the game and sold off their stock to the company selling them on ebay). They're on ebay though for the same price as 1000 watt.

For that cheap though, I wonder how the quality is.... For 100 bucks, I'd love to try it.
 
I think you are spot on. My experience and research has me at the same conclusion. It seems the real quality class D are very expensive and some high end audiophile manufacturers like PS audio even use a tube in the circuit of their class D amps. Alot of guys like the powerstage stuff...I just don't think I would be one of them.
 
I don't know of you noticed this one, but it's the plate that Xitone uses. I is a little pricey but if you are a DIY'r it could still be cheaper to do it yourself.

https://www.parts-express.com/Dayto...800W-2-Channel-with-DSP-and-Bluetooth-300-798

@Justincase, building at least one box with a FX12 is on my bucket list. What amp are yo using with them?
Brother I'm using a cheap Behringer xps4000 class H to drive two f12x cabs and it rocks. I was surprised. But happy cuz it put my total build/amp cost at 650. That plate amp you posted if for a two way speaker. Not sure it would work with a coaxial f12x cuz it has a crossover built in. It may tho. Not sure what driver the OP is using.
 
Brother I'm using a cheap Behringer xps4000 class H to drive two f12x cabs and it rocks. I was surprised. But happy cuz it put my total build/amp cost at 650. That plate amp you posted if for a two way speaker. Not sure it would work with a coaxial f12x cuz it has a crossover built in. It may tho. Not sure what driver the OP is using.

I'm only using 2 guitar speakers. No need for a crossover for a tweeter or a coaxial speaker.... I'm giving some thought to the B-52-ACT-15x though.... would be nice of the Matrix GM50 were still sold
 
I don't know of you noticed this one, but it's the plate that Xitone uses. I is a little pricey but if you are a DIY'r it could still be cheaper to do it yourself.

https://www.parts-express.com/Dayto...800W-2-Channel-with-DSP-and-Bluetooth-300-798

@Justincase, building at least one box with a FX12 is on my bucket list. What amp are yo using with them?

I see that Xitone is using that amp now. They used to use the Matrix GM50, didn't they? Interesting they moved from Class AB to Class D
 
SA sells plate amps too. Not sure how they are tho. Just another option.
https://www.seismicaudiospeakers.com/collections/amps-mixers

if i go this route with plate amps, which are typically made for FRFR speakers, I'm assuming they have built in crossovers and stuff for a speaker / tweeter combination. What do I need to look for to ensure the amp has the ability to disable the crossover so that it works for my cab?

Also not 100% certain I want to go this route, but it may be a good option....
 
I think some have built in crossovers and some don't. Id contact SA or parts express and talk with them. Tell them exactly what you are wanting to do. PE has really good customer service and can point you in the right direction. Cheapest and easiest route imo is just a stereo rack amp but if you're using an FM3 I can see how that wouldn't be ideal. I'm running Axfx3 and had extra rack space anyway.
 
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