New Class A
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MunkeyQ
Super Member
As far as I know, New Class A is a marketing term used by Technics for their class AB chipamps. The bias is controlled by a microprocessor, which changes with the output signal, keeping it in running in Class A for longer as the current is more precisely controlled. Or at least that's the jist of their marketing info...
IMO, the bigger Technics New Class A amps with the grey fronts are very nice sounding, and can be got fairly cheap too. The TOTL one even has dual mono power supplies.
IMO, the bigger Technics New Class A amps with the grey fronts are very nice sounding, and can be got fairly cheap too. The TOTL one even has dual mono power supplies.
mhardy6647
Lunatic Member
some kind of sliding bias dealie. Quasi-class A designs that are more efficient than actual class A operation were all the rage starting in the very late 1970s (and persisting in some circles up to this very day).
Glen B
Super Member
New class A is a dynamic/sliding bias system that is supposed to reduce crossover distortion, resulting in the benefits of true class A, without its drawbacks (heat and inefficiency). Technics was not the only manufacturer to employ such biasing. Pioneer and Nikko also employed dynamic bias systems. Pioneer called their amps "non-switching" designs. Today, manufacturers like Krell (sustained plateau bias) and Classé employ adaptive bias systems that vary bias according to demand, resulting in high class A operation up to a point, then class B above.
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Glen B
Super Member
See the following link to a diyAudio solid state forum thread on dynamic bias. Search diyAudio for more specific discussion on Technics new class A.
http://www.diyaudio.com/forums/pass...-self-biased-overview-wanted.html#post2158850
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RadShak1251
Super Member
The Technics gear with "New Class A" (or "Class H+" in their later series in the 90s and early 2000s) that I'm familiar with may have had relatively less heat generation, but they still ran hot as hell compared to their competitors' A/B amps. :yes: (btw I'm a fan of Technics gear in general so am not complaining about it).
This is based not on internet heresay but actual experience, while selling Technics receivers in the mid 90s and owning one of their receivers bought new for nine years now, an SA-DA8. Even while idling with the volume turned all the way down or no signal being sent from a source component, the metal in/around the cooling vents on top of the receiver can become so hot that most people can only keep their hand there for a couple seconds at the most.
* What's weird is that their internal cooling fan, if equipped, only turns on when the volume reaches a certain level, usually around 10:00 on the dial (if using a mechanical/potentiometer-based knob - my SA-DA8 does, the last one for Technics AFAIK), which with my Boston CR9s is already loud enough to easily prevent a normal conversation.Btw I never worried about the Technics new class A heat issue because car audio gear can last years and years, and look at the conditions they operate in. And related to that: Technics engineers must have done their Q.C. homework because Technics was our most reliable receiver brand, despite their heat-generating ability.
Lastly, I found this thread last month and bookmarked it:
"New Class A, Super-A, Non-Switching : need a revival ?"
* some customers would change their mind about buying a Technics receiver for that one reason. Fun factoid: my SA-DA8 can literally help heat my 11ft x 14ft mancave, enough that in the summer sometimes I have to open the door; Me? I think the hot-as-hell amp feature gives Technics receivers "personality", weird but true.
Glen B
Super Member
I owned Pioneer and Nikko amps with dynamic bias in the '80s and they did not run hot. I guess Technics gear were a different sort of animal.
terra1
Addicted Member
I have a Technics SU-V9 with New Class A. It does not get hot. It sounds smooth. Liquid smooth. There are also versions like the SU-V909 with computer drive.
Do a search and there are lots of threads defining and discussing New Class A. Several in the last few months actually.
Do a search and there are lots of threads defining and discussing New Class A. Several in the last few months actually.
Let's not forget Sony's Legato Linear. 
Cobaltturbo
Member
The accuphase E-408 I just sold does the same thing. Class A up to 8 watts or so and then switches to class AB above that. Not exactly sure of the cut off point. Nice unit although I switched to their class A amps and they are without a doubt much more open and dynamic sounding but at a far greater cost and expense to use.
Glen B
Super Member
The Accuphase does not do the same thing. It is a high bias amp, not a dynamic or adaptive bias amp. All class AB amps run in class A up to some point determined by the standing bias, before running in class B. This could be anywhere from a few milliwatts to several watts. The Accuphase is just a regular high bias amp, allowing it to run in class A up tp 8 watts (approx. 4.5% of rated output). The amps I mentioned above vary bias according to the input and/load. A Classé amp of similar power to your Accuphase runs class A up to approx. 40 watts (20% of rated output).
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