Power amp sections in bassheads

[gtirard]

Ref: What is Class G/H Amplifiers? - PSI Audio
View attachment 4845063

Maybe this will help. Still from someone's slick brochure, but a very basic explanation of how Class G differs from others.
https://www.arcam.co.uk/ugc/tor/avr850/Class G Explained/Class_G_the_ultimate_amplifier_technology_150714_A.pdf

Thanks. I think I get the idea. I understand it's more efficient than class A/B, so it may offer a good alternative for people who don't want to hear about class D. What i don't understand is why some people hate class D?

 

[JeezyMcNuggles]

You are not contradicting my statement there. The point is that you are wrong about "all made in China".

Yeah, okay

 

[Sparky Mark]

Thanks. I think I get the idea. I understand it's more efficient than class A/B, so it may offer a good alternative for people who don't want to hear about class D. What i don't understand is why some people hate class D?

I think some people have disliked amplifiers that have class D power sections and believe it's the power section that's the issue. That may be the case but like every type of amplifier some are created better than others. I've owned some amps of both class AB and D that I didn't much like and I'm not sure the topology was the issue.

 

[SJan3]

Hello TalkBass!

Is there an existing thread about what bassheads have what power amp sections?

There's lots of talk that many class D amps are using same or similar power amps (ICE or something). I don't need a thousand watts, so I'm thinking of just getting a used class D amp (even if I don't like the preamp sound) and use my own preamp plugged into the effects return. But first it would be interesting to find out more about the different power amp sections in different heads...

What companies are creating their own power amps?

Where could I find info about third party power amps used in bass heads?

MarkBass uses their own power amp section called MPT. Their amps always seem to have plenty of power for their respective ratings.

 

[Plain Old Barry]

Are there some simple power amps that are ~800W and the size of a small class D head?

Yes on the first point, but probably all will be rack mount format.

Here is a sub-8 pound example: Behringer NX3000 3000W 2-channel Power Amplifier

 

[azureblue]

Yes, and in this case, when the country of origin is stated as China, it has to be a counterfeit product since the genuine product is manufactured in Malaysia.

I think you're right here - IIRC the "real" ones have the B&O ID on the lower left corner of the circuit board. When I bought a replacement for my GKMB212 power amp, I was warned to look for the ID. and to double check. I think the caps look different, too. GK advertises the MB212 at 500 watts, but I'm not going to quibble because it's loud enough for me. But the really great thing was it was an exact drop in down to the mounts and the connectors..
GK has it set up for one channel for the tweeter and the other for the speakers - the circuit board labels for that. But the specs sheet and hobbyist sites show how it can be used as a stereo / mono amp. Ebay has some dealers selling it in a case for home stereo use. I found a couple of papers on it --
It comes with connectors, too.

 

[shinju]

This seems small and inexpensive for a 800W ICEpower amp:
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https://images.thomann.de/pics/atg/atgdata/document/manual/424520_c_424520_v2_r2_en_online.pdf

 

[Wasnex]

What i don't understand is why some people hate class D?

Human nature.

 

[Old Garage-Bander]

Thanks. I think I get the idea. I understand it's more efficient than class A/B, so it may offer a good alternative for people who don't want to hear about class D. What i don't understand is why some people hate class D?

Well there are those who have a tube bias (pun intended). Or they just like tubes. And that's OK.
But there is also a lot of misinformation and misunderstanding about Class D amplifiers.

One of the more prevalent is the the D stands for digital. It's more likely that D was just the next letter for a class naming convention that has been in place way before class D was a thing. Class A, B, C, D. If what we now call class G came along first, it might have gotten the D instead.

The early classes, A, B, C, and their derivatives were based on how much time a device spent conducting the input signal to the output. Class D amps also have conduction times, but not in the same sense as the previous classes. Class D uses pulse width modulation schemes, PWM. The analog input information is converted to pulses that relate to the instantaneous input signal. While PWM can be used to encode analog information into digital information, that's not how it is used in Class D amplifiers. But this is where some of the confusion and misunderstanding occurs.

There is still, after all these years, some folks who hold that analog audio is always superior to digital. In the early days this was a valid argument. And depending on how a digital signal is manipulated these days, can still be a valid complaint. But those manipulations are more related to how digital audio is over-compressed or otherwise "processed." Similar manipulations occur in the analog world. We must not fault the method, but rather how it is used, or misused.

So even if Class D involved encoding audio into a digital stream of information, WHICH IT DOES NOT, it wouldn't be the digital per se, that is bad. Rather it is what we do with it while it's in the digital realm.

Class D amps do an excellent job of converting analog audio into a form that can be amplified more efficiently, and then recover the audio from it's intermediate form.

My background is in broadcasting technology. Virtually every AM or FM station you could tune to in the 60's when all audio was analog and tubes were still in abundant use, sound inferior to those same stations today. Many of them now don't have a tube anywhere to be seen. And they convert analog audio to digital, manipulated it, broadcast it, and your receiver recovers it and either decodes or demodulates it as is appropriate, to analog audio that sounds far better than it did in the '60's.

We are aware that classes A, AB, B, and C can all be, and have regularly been, implemented with tube and solid state devices. While it is not practical to use tubes to creat a class D amp, I believe it could be done, at least as an academic exercise. What would the tube folks think of that?

Here are a couple of links that discuss (and dispel myths related to) PWM and Class D without getting overly technical.
How do Class D amplifiers work?
Pulse Width Modulation - Definition, Terminologies, Types, Applications

 

[watt]

bassslinger jimmy,

thank you much, groping around for meaning lots, trying to make some sense.

you got a good way w/words, much respect to you.

on bass, watt

mike watt's hoot page

I get what you’re saying, Mike. It’s the core but everyone can still put their own stamps on the sounds by the design goals. I’m not a big tech head but I think that makes a lot of sense.

 

[JimmyM]

bassslinger jimmy,

thank you much, groping around for meaning lots, trying to make some sense.

you got a good way w/words, much respect to you.

on bass, watt

mike watt's hoot page

Whoa, well thank you very much Mike. Much respect to you as well, sir!