Why did Class H amps never really catch on?

[restorer-john]

I think that John @restorer-john might remind me if there was a commercial amplifier (Crown? edit: Technics SE-A1 ) based on this principle.

Yamaha B2-X also is somewhat similar, except they do it the other way around. A super accurate low power, low voltage rail +/-3V (fixed not floating) and a high powered AB stage +/-70V to absorb power loss.

Service manual is on HiFi engine. I have an original brochure if you want a copy. (I'll scan it over the weekend and upload it to HiFiEngine)

 

[chelgrian]

Sure it didn't catch on... the Crest 4801, 6001, 7001, 8001, 9001, 10001, 10004, CA4, CA6, CA9, CA12, CA18, just didn't exist. Hell, Crest, QSC, Camco and a whole bunch of others just don't exist.

Class H caught on in the pro world, but big amps really aren't that common in an audiophile setting. Usually you only see Class G and Class H in amps that are more than 300 WPC.

Indeed it was the only way to make high power amps with a 'reasonable' PSU However a crest CA18 still weighs in excess of 20Kg.

The pro world has now largely moved to class D with switching PSUs due to the weight advantages either with flown active cabinets or flown amp racks.

 

[restorer-john]

I have an original brochure if you want a copy. (I'll scan it over the weekend and upload it to HiFiEngine)

@pma

I've uploaded it to HiFi engine, but it may take several days before itappears on the site. Here's a link to the B2X brochure I scanned at a pretty high res as it has quite a lot of detail:

https://drive.google.com/file/d/1JMGYBHnCCsbzTtrV4B0LYjtBsPSum2rT/view?usp=sharing

 

[JSmith]

It never caught among audiophiles on because Class H is like Class A, but a bit too open in the top.

Class type is irrelevant and your comment makes no sense... it comes down to design and implementation, not amp class type. If two amps measure the same, they measure the same.



JSmith

 

[Unground]

Class type is irrelevant and your comment makes no sense... it comes down to design and implementation, not amp class type. If two amps measure the same, they measure the same.



JSmith

It was in jest, no?

 

[pma]

Class type is irrelevant and your comment makes no sense... it comes down to design and implementation, not amp class type. If two amps measure the same, they measure the same.



JSmith

If you go in deep, you never get absolutely same set of measurements from two different amps.

 

[pma]

@pma

Here's a link to the B2X brochure I have scanned at high resolution so the diagrams are really clear when zoomed:

https://drive.google.com/file/d/1JMGYBHnCCsbzTtrV4B0LYjtBsPSum2rT/view?usp=sharing

Thank you John, appreciated! I will download it in a while.
Edit: downloaded!

 

[JSmith]

It was in jest, no?

Shit, maybe it was then... hard to tell anymore. If it was, I've been done in.

If you go in deep, you never get absolutely same set of measurements from two different amps.

Yeah I know, I mean generally and within the limits of audibility etc.



JSmith

 

[mocenigo]

Class type is irrelevant and your comment makes no sense... it comes down to design and implementation, not amp class type. If two amps measure the same, they measure the same.

WHOOOOSH! (The H is like an A, but with an "open top"...)

 

[mocenigo]

It was in jest, no?

I admit, not my best joke.

 

[JSmith]

WHOOOOSH!

Yeah that went through to the keeper... just a tad askew.

I admit, not my best joke.

Hey better than no joke at all... some threads need a bit of lightening up at the best of times.



JSmith

 

[tonycollinet]

It was in jest, no?

Shit, maybe it was then... hard to tell anymore. If it was, I've been done in.

....
JSmith

I admit, not my best joke.

That's Poe's law for you

 

[Hapo]

Class D is not ready for prime time, plus the decent sounding ones cost a lot.

...all of this is so far above my head I should not be posting but class D reminds me of digital photography...initially eschewed by professionals...

...who uses Kodachrome today...???...

 

[mocenigo]

Class D is not ready for prime time, plus the decent sounding ones cost a lot.

Did I already say this is completely wrong and you are to the very least uninformed?

 

[Goodman]

Did I already say this is completely wrong and you are to the very least uninformed?

Seriously, class D amps costing thousands are trying to catch up to near state of the art class AB amps you can pick up on the used market for three to 400 hundred, Euros. Have a listen.

 

[mocenigo]

Seriously, class D amps costing thousands are trying to catch up to near state of the art class AB amps you can pick up on the used market for three to 400 hundred, Euros. Have a listen.

Seriously, you can have a < 2K USD Purifi build with Neurochrome buffers that beats any state of the art Class AB amp even if you spend tens of thousands of dollars on them. Have a listen.

 

[Chr1]

Seriously, you can have a < 2K USD Purifi build with Neurochrome buffers that beats any state of the art Class AB amp even if you spend tens of thousands of dollars on them. Have a listen.

I think that the point is that for 400 Euros there are a lot of very good A/B amps available second hand. This is not the case with Class D (yet).

 

[Chr1]

Picked up one of these in mint condition for £100 a couple of years ago. Haven't actually used it as yet. It is built like a tank.

Perfect subwoofer amp, I reckon.

LD Systems LDPA1600X

 

[mocenigo]

I think that the point is that for 400 Euros there are a lot of very good A/B amps available second hand. This is not the case with Class D (yet).

I realised that, but I think we should be close. A NC502MP based amp can be found for about 800€, so the used price should be as low as 500€.


A NC252MP based amp should be in the target range.

EDIT: in fact, this one was sold for about 400€ https://www.canuckaudiomart.com/details/649669840-vtv-amplifier-hypex-ncore-nc252mp-stereo-amp/

 

[mhardy6647]

...all of this is so far above my head I should not be posting but class D reminds me of digital photography...initially eschewed by professionals...

...who uses Kodachrome today...???...

Well... no one, since it's no longer made.
Some folks do still use film, though -- just as some folks do still use vacuum tubes.