Class H amps?


Just came across 'Class D' (after years of A, AB, not really B). 

So what is Class H? How does it differ from Class D?

 

kraftwerkturbo

Can an analog Class H still have (would make sense) a switched mode power supply (LOTS of weight saving right there)? 

Absolutely.  This seems to be what the NAD Hybrid amps are doing, but they have very very little information out in the public domain.

Yamaha's EEEngine amps also have this type of design. 

One engineering difficulty about Class H though is the voltage rails have to anticipate the signal peaks.  There's some interesting discussions online about Yamaha's implementation, distortion, and fixes.  Class G solves this problem by having multiple rails available all the time, but this adds to the possibility of distortion when those rails switch.

My Soundcraftsmen A400 became scary good, after removing the wimpy power cord and hotwiring a 10 ga power cable I built to replace it, and, creating a 2ndary ground. Took this amp to another level. Power cords make a difference. Anyway, having owned many Soundcraftsmen products, I kind of know the story of Paul Rolfes, who was the chief engineer at Soundcraftsmen, and happens to be credited with the development of the signal-tracking multiple-rails power supply, as well as other patented circuits, which led to his development of Class H. When MTX bought out Soundcraftsmen, it was quite soon that they shut down the line, which was imo unfortunate, as the products ( for me, specifically power amps ) were quite good. Just some history. Enjoy ! Always, MrD.

@mrdecibel what other models aside from the A400 are in that 'group' (with respect to powe and sound quality)? Does the A-5002 fall into that category? 

@kraftwerkturbo , The A400 ( and A400 Pro ), S800, S840 and S860 all use the PCR circuitry, but I am fairly certain they were not categorized as Class H ( there were other models as well ). The A-5001 and A-5002 are Class H. Some differences in sound between the models, but a fully up to date ( re-worked and overhauled, after many years ) unit, imo, can easily hold it’s own with what is available today. With my dozen or so SC units owned, I never experienced a failure, but there are reports out there that differ from mine. There are some interesting readings on the net about the SC products. I hope this helps. My best, always, and Enjoy ! MrD.

Mr decibel- in case u r interested I have some soundcraftman amps for sale. A400PRO, A200PRO AND AN A900PRO. ALL IN GOOD WORKING CONDITION. LTDVIEWHOMES@GMAIL.COM