|
Post by AudioHTIT on Nov 9, 2019 1:07:23 GMT -5
If that means something to you then great, go with it. What’s important (for this discussion) is how much of the time your speakers in your room at your listening levels, a given amp spends in Class A (presuming the more the better). Your original question, which implied you want to know at what wattage it transitioned from A to B, was useful, a quantifiable value you could use to determine how your speakers/room/habits might interact. An opinion about whether they’re “more bias towards class A than B” is not. If you find that funny, ok. What I meant to ask is, at some point do class a/b amplifiers act more like a class b amplifier than a class a or a/b design when pushed hard or do they not? Yes, all Class A/B amplifiers operate in class B above the bias point, Keith has given us that as a ‘few watts’. This is actually somewhat significant as most listening is done at a watt or less, which would be all Class A for the amps in question. garbulky ’s XPA-1G2’s are rather unusual in their ability to deliver 60 watts of Class A (when switched), but they too then become Class B. For many years I had an amp that could deliver 200WPC (it’s rated output) in Class A, but it used Nelson Pass’ unique Dynamic Biasing. In the end you listen to music through the amp and you like it or you don’t, these are interesting things to know and understand, but be careful how you value them.
|
|
|
Post by Gary Cook on Nov 9, 2019 3:21:19 GMT -5
What I meant to ask is, at some point do class a/b amplifiers act more like a class b amplifier than a class a or a/b design when pushed hard or do they not? Yes, all Class A/B amplifiers operate in class B above the bias point, Keith has given us that as a ‘few watts’. This is actually somewhat significant as most listening is done at a watt or less, which would be all Class A for the amps in question. garbulky ’s XPA-1G2’s are rather unusual in their ability to deliver 60 watts of Class A (when switched), but they too then become Class B. For many years I had an amp that could deliver 200WPC (it’s rated output) in Class A, but it used Nelson Pass’ unique Dynamic Biasing. In the end you listen to music through the amp and you like it or you don’t, these are interesting things to know and understand, but be careful how you value them. The XPA-1 Gen2's (60 watts) and the XPA-1L's both Gens (30 watts) have switches that "hold" them in Class A and in my case the 30 watts is more than enough volume to rock. The most noticeable thing about flicking the switch is heat, quite a bit more generated in Class A. Sound wise its very hard to pick, not at all a night and day revelation. Cheers Gary
|
|
|
Post by benbvan on Nov 9, 2019 3:43:22 GMT -5
What I meant to ask is, at some point do class a/b amplifiers act more like a class b amplifier than a class a or a/b design when pushed hard or do they not? Yes, all Class A/B amplifiers operate in class B above the bias point, Keith has given us that as a ‘few watts’. This is actually somewhat significant as most listening is done at a watt or less, which would be all Class A for the amps in question. garbulky ’s XPA-1G2’s are rather unusual in their ability to deliver 60 watts of Class A (when switched), but they too then become Class B. For many years I had an amp that could deliver 200WPC (it’s rated output) in Class A, but it used Nelson Pass’ unique Dynamic Biasing. In the end you listen to music through the amp and you like it or you don’t, these are interesting things to know and understand, but be careful how you value them. yes I had thought that an AB amp acted in class A up until a certain point, and then was a combination of both class A and B technologies, sounding better than class B and being More efficient than class A, but still a combination of both. And different class AB amplifiers would be more class A leaning than B, and some more class B leaning than A.
|
|
|
Post by emotifan on Jan 6, 2020 12:40:30 GMT -5
I'm a little late to this party but it seems that you are misinterpreting what a class A/B amp does. It doesn't transition from pure class A to class B at some point in it's output range, it's always running in class A/B. I thought the same thing for quite some time but searched out an explanation and discovered what class A/B actually is. Following is a link to an excellent description of how different Amp classifications work. www.electronics-tutorials.ws/amplifier/amplifier-classes.html
|
|
|
Post by garbulky on Jan 6, 2020 12:50:06 GMT -5
I'm a little late to this party but it seems that you are misinterpreting what a class A/B amp does. It doesn't transition from pure class A to class B at some point in it's output range, it's always running in class A/B. I thought the same thing for quite some time but searched out an explanation and discovered what class A/B actually is. Following is a link to an excellent description of how different Amp classifications work. www.electronics-tutorials.ws/amplifier/amplifier-classes.htmlIf I'm not incorrect if the bias voltage is high enough, the class A/B amp does operate in class A until the bias is exceeded at which point it slips to class AB or class B operation. Maybe I'm misunderstanding the finer points of this.
|
|
|
Post by benbvan on Jan 6, 2020 13:23:58 GMT -5
I'm a little late to this party but it seems that you are misinterpreting what a class A/B amp does. It doesn't transition from pure class A to class B at some point in it's output range, it's always running in class A/B. I thought the same thing for quite some time but searched out an explanation and discovered what class A/B actually is. Following is a link to an excellent description of how different Amp classifications work. www.electronics-tutorials.ws/amplifier/amplifier-classes.htmlIf I'm not incorrect if the bias voltage is high enough, the class A/B amp does operate in class A until the bias is exceeded at which point it slips to class AB or class B operation. Maybe I'm misunderstanding the finer points of this. That's what I thought.
|
|