Planning on buying one from a friend but he doesn't have it set-up anymore. All I know is it is a Pure Class A design. Anyone heard anything about this brand or heard this amp? Thanks.
I am interested by Kinergetics as there was a claim for them as having no "hysteresis" distorsion. I've not found circuits or schematics related to these amps yet.
Hi Excetera2,
"Hysteresis" distorsion. It's a marketing term used by Kinergetics, I think. I suppose it means that a circuit having hysteresis has its operating points affected by the immediatly previous signals which has been treated, the cause may be, for example, thermal effects.
"Hysteresis" distorsion. It's a marketing term used by Kinergetics, I think. I suppose it means that a circuit having hysteresis has its operating points affected by the immediatly previous signals which has been treated, the cause may be, for example, thermal effects.
Their thing was putting all kinds of weird stuff into the feedback loop to compensate for "hysteresis." For example, you'd find a bunch of solder joints in series.
Did you hear any of these amps? Did they sound good? I don't see what the solder joints in series would do but whatever. I have never heard a pure class A amp. Do they sound similar to AB's or no? Thanks.
The idea was to compensate for the "sound" of all the solder joints. Same deal with their preamp- they had a phono cartridge (sans stylus) in the feedback loop.
I wouldn't comment about the sound, since I never had one in my own system; since the idea never caught on, I doubt that this was anything special.
I wouldn't comment about the sound, since I never had one in my own system; since the idea never caught on, I doubt that this was anything special.
K. How does Class A sound compare to Class AB stuff. Will this thing just get a lot hotter? I was either going to get the Kinergetics stuff or a B&K Ex-422 just to play some bookshelfs I built. The B&K has a lot more power, but I don't need it. I was trying to decide.
I think generalizing on that would be ill advised. There are good and bad class A amps, good and bad AB amps. The idle current is just one parameter in a complicated mix; it's like asking, "Is a soup better with more or less salt?"
How much idle current do Class A's usually draw? Is it much more than AB's. Are they pretty inefficient even with no signal fed to them or do they have some sort of shutoff?
A true class A amp draws the full current it is capable of at all times. They are stunningly inefficient. This is why so many manufacturers cheat and call an AB amp with sliding bias a "class A" amp. I mean, it's class A! Class A! That's got to be better than Class B! After all, a grade of A is much better than a grade of B in school! I think that this psychology, along with hair-shirt audiophilia, is more responsible for class A's reputation than any real sonic advantages (just my opinion after 40 years of playing with this stuff).
Rule of thumb: if it's a 100W class A amp, it had better be monstrous big with huge heatsinks and put out waves of heat. If not, it's not actually class A except in the marketing sense.
Rule of thumb: if it's a 100W class A amp, it had better be monstrous big with huge heatsinks and put out waves of heat. If not, it's not actually class A except in the marketing sense.
Hi SY,
I think you definition of class A relates only to single-ended, I made the same error just a few days ago on a french forum.
The real definition of class A is that neither branch of the push-pull ever ceases conduction. Both branches are always in conduction.
With an idle current of 1 A, a push-pull amp can deliver 1.99 A to the load, there is 10 mA passing through the other branch and it still class A.
Is sliding class A real class A ?
Audibly, I won't say anything.
By definition, it should be because classes are defined by the various possibilities of conduction of the branches not by the idle current :
class A : both branches are always conducting
class B : one branch at least is conducting
class C : branches are never conducting at the same time
May I suggest this link to class A amps fanatics
http://www.audiodesignguide.com/PowerFollower/
This is the only amp I am aware which draws a constant current from the power supply and is in a shunt mode with the load, just like some voltage regulators.
I think you definition of class A relates only to single-ended, I made the same error just a few days ago on a french forum.
The real definition of class A is that neither branch of the push-pull ever ceases conduction. Both branches are always in conduction.
With an idle current of 1 A, a push-pull amp can deliver 1.99 A to the load, there is 10 mA passing through the other branch and it still class A.
Is sliding class A real class A ?
Audibly, I won't say anything.
By definition, it should be because classes are defined by the various possibilities of conduction of the branches not by the idle current :
class A : both branches are always conducting
class B : one branch at least is conducting
class C : branches are never conducting at the same time
May I suggest this link to class A amps fanatics
http://www.audiodesignguide.com/PowerFollower/
This is the only amp I am aware which draws a constant current from the power supply and is in a shunt mode with the load, just like some voltage regulators.
If you accept that definition, as opposed to an operating angle definition, then ALL amps are class A, since even at cutoff, there's some current flowing.
Two things: First, I think Poobah should be a standup comedian. His "It's good that so many can spell historheesus though..." comment still has me howling. I don't want to sit in the first row, though. Second, I think that there Mark Levinson ML-2 qualifies as full class A. 25 Watts into 8 ohms (mono), 6 amps from the wall at idle. You could make waffles on it. It drew less current from the wall at clipping.
excetara2 said:
I think most of the Kinergetics stuff was designed by Tony Di Chiro. It was fairly well built stuff. I'd put it in the Aragon/Bryston/B&K build quality. Stereophile has a couple of online reviews for their products that are favorable.
If you know the model number, I can give you a few more details about it.
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