Pure Class A amps above 100 Watts?

My Gryphon Colosseum draws 500w while idling

My water cooled one I built, drew over 2500w at idle, with 230v mains, and had a special h/d power point, as the normal 10amp ones use to get hot and give connection problems over time.
When this beast was switched on with the 5kva transformer, 45A bridges, 1/2 farad of supply caps, the mains wire from house barge board to the street pole used to flex up and down 6" for a second.

This amp ran my Acoustat 1+1
https://i.ebayimg.com/00/s/MTYwMFg5MDA=/z/bkAAAOSwlddc1IW9/$_1.JPG
crossed over passive 18db at 80hz to two very rare Kef B1814’s in 11cu ft vented sub enclosures that Neville Thiel (rip) designed for me after measuring the B1814’s, the system ended up flat to 18hz.
http://i66.tinypic.com/nnr1fr.jpg

Cheers George

larrykell

Do you have any pictures of that water cooled amp? Nothing succeeds like excess. I owned a Mac computer that was water/liquid cooled. It weighed a ton. How much did your amp weigh?

OK you asked for it, believe it or not time.

Sorry no pics, young and stupid back then, all I wanted was was biggest Class-A I could make using water as cooling, after I built and heard Nelson Pass A20 http://www.firstwatt.com/pdf/art_classa_20.pdf also they were film cameras back then and no internet so pics were a hassle.

It weighed a lot, and was a two man lift in the order of 100kg, that power supply fed some for memory 36x Hirel EB and ED 204 bjt transistors 20amp 200w 200mhz each, one of the best transistors eve made, no longer available.

The amp was on a naked platform 1mt X 1/2mt, which had a machined water cooling jacket which all those hirel’s bolted to the outlet hose went to the top of a small car radiator, the bottom hose of the radiator went to a very quiet pump which then went to the inlet of the water cooling jacket. I had a Garard turntable motor with a Davis Craig plastic fan on it turning at 33 rpm to blow air through the radiator.
The whole thing after 10 years started to corroded, I very rich businessman offered me a fortune for it as a resto project and I sold it to him, he may still have it, but I doubt it, even the 1/2 farad of caps were on the way out.

I was a trip making it a showing it off, one of the times it powered Otto Majors system (rip) Quad 57 restorer extraordinaire even better than original.
He had double stacked quad 57’s with Decca Kelly ribbons from 10khz up, and from 100hz down two 24" Hartly woofers in the wall where the room behind it was the speaker box.
Front end was a Linn of course with an Infinity Black Widow arm and a Stax Electrostatic!!!! best ever sounding cartridge, going into it’s own power supply and riaa, which then went into my Lightspeed Attenuator MkI passive and into the water cooled beast! What a sound, remember the Dire Straits album "Love Over Gold" very well it was holographic!!.

http://mniec.files.wordpress.com/2012/11/hqdusa_resize.jpg?w=594&h=413

https://i.pinimg.com/originals/ff/28/0e/ff280e10ff8268ed43348aa59b805d2a.jpg

https://farm8.staticflickr.com/7479/16018366265_aeda7012db_b.jpg

https://www.vinylengine.com/turntable_forum/viewtopic.php?t=23803

Cheers George

Nobody but you George has ever questioned that these operate in Class A

It's a play on words.
 " 300 Watts continuous rms into 8 ohms in Class A
   600 Watts continuous rms into 4 ohms in Class A"  

If this above is to be believed as your are believing, it would be worded like this instead.

"300w pure Class-A into 8ohms
 600w pure Class-A into 4ohms"

but will say the amps do sound good, and particularly for the cost.

I'm not saying they sound anything but good.
 I'm disputing how they advertise the Class-A ability of them, especially with no fans and top mounted flat heatsinks like that, there is no convection cooling at all, they'd be lucky to be 50w Class-A

Cheers George


   

Sorry Mitch you been had, this is A/B what you think is Class-A.

"Class A Operation / Fully Balanced / XLR Inputs Only"

This is not an indication of 300w Class-A.

"300 Watts continuous rms into 8 ohms"

This is an indication of rms watts Class-A/B

"Power Consumption: Low Bias Mode - 300 Watts"

This is the "power consumption", not the Class-A bias

"Power Consumption: High Bias Mode - 800 Watts"

This again is the "power consumption", not the Class-A bias

If this amp had the Class-A bias you think it has it would be the size of a house!!

Here is an example of what heat sinks are needed to have just a 25w Class-A mono block amps with nothing over 25w (no Class-B at all) if it were say 50w of A/B the "heatsink area" for the same 25w of Class-A would more than double.
They are the famous 25w Class-A Mark Levinson ML2 monoblocks, but that’s all they had 25w!!!!
https://ibb.co/d6zvmMR

Cheers George

Not with the way those heatsinks are arranged, and they don’t say 300w Class-A. They say 300w into 8ohms which will be a/b with a few watts of Class-A bias.

Again power consumption is rated at 300w, big difference to how much Class-A bias is on them.
M300 - 300 watt monoblocks


Cheers George

This was a sales marketing error!! The 125wpc is draw when at idle.

So true as I explained above, MF have a habit of doing this, so do many others it needs to be shut down,claims of large amount of Class-A bias on A/B amps with heatsinks too small for what they claim.

Also there's a practice of wattage doubling for each halving of load impedance (EG: 8ohms100w, 4ohms 200w ect ect) many do this by first understating the 8ohm wattage so the 4ohm looks like it's doubling. 

Cheers George

mikethehunterguy
125wpc Class A. 400wpc AB.

Sorry Mike impossible, a 400w Class-A/B amp with 125w of Class-A bias would have to have heatsinking 10 x more of what they have on this.

At a guess that heatsink with the rail volts needed for 400w a/b, could accommodate at most around 20-30watt of Class-A, without any serious fan forced cooling.
As the rail volts go up for more A/B wattage, the Class-A heat factor to be dissipated goes up exponentially for each watt of class-A

I built a 200w A/B amp that had 150w of Class-A bias, the only way was to water cool it. It was the size of a coffee table, and a 2 man lift.

Cheers George

Gryphon Antileon Evo monoblocks 175w Class-A, I believe will trump all others

https://gryphon-audio.dk/shop/power-amplifiers/antileon-evo-mono/

Then if you don't have the funds for them you get the Antileon Evo stereo, with 150w Class-A

https://gryphon-audio.dk/shop/power-amplifiers/antileon-evo-stereo/

And then Mephisto and Colosseum and so on 
  https://gryphon-audio.dk/wp-content/uploads/2018/10/Technical_Specifications-4.pdf
 
Cheers George