Class A Power Amp Degredation


Dear Forum Members,

I've read in several places that because class A amplifiers run hard all the time and most people don't cut them off, they wear our faster. Plus, because they remain on all the time they burn much more electricity and generate lots of heat, some more than others, at least that's what I'm told. I wonder what happens if I have to go away for a day or two?

I can't afford to purchase a brand new class A amp so I wonder if I should even consider the purchase of a used Mark Levinson, Pass Labs or other class A amp? The only amplifier I know of that can be switched between class A and A/B is the Plnius. I am told that this amp only run very hot when it's running in class A.

Here are my questions:

1. What should I look for in a used amplifier?
2. Do class A amps wear out faster than other amps?
3. Are there amplifiers that can match the musicality, sound staging, bass and sweet sounds of a class A amp? In other words are there any class A/B amps that have all of the quailities of the class A amps?
4. If I do decide to buy a class A amp how far back in years should I venture? Right now I am considering the Mark Levinson 27 or 27.5 or Pass Labs X150/250 and X150.5 and X250.5 amplifiers. It's been suggested that the Mark Levinson is more musical????? I just want to get the best amplifier to run my audio system.

I will be driving Magnapan 1.6 speakers which does require a fair amount of amps/power to drive them. Also I mostly listen to classical music, large/small scale choral works, contemporary and gospel music and all modern jazz. I love the human voice. I also love a huge sound stage with lots of depth perspective.

Any assistance and suggestions you can provide will be very welcomed. Thank you so much for taking of your time to respond to this plea for help.
rbwinterlink

Showing 2 responses by guidocorona

Rbwinterlink, in general it is best to turn off your system if you leave home for a few days regardless of the class of operation of your amp. . . besides power consumption concerns for all class A amps and many class A/B amps, there is the issue of inclement weather which can cause power outages, spikes, and worse.

Pure class A amps are -- as far as I know -- always furnaces. . . . as they draw current at the same peak value regardless of what they are doing. . . whatever is not used for making music goes up in heat.

Things become more murky with class A/B devices. Some are veritable furnaces like the Pass X.5 series and my old Rowland 7M monoblocks. . . others run as cool as cucumbers like the Theta Citadel monos -- one of the sweetest amps I have ever heard.

Then there are switching amps -- mostly class D -- that most often run very cool to the touch and have operating efficiency ranging from 85% to 98% depending on manufacturers and models. In most cases these amps have output properties (high damping factor of 500 to 1000) that make them particularly suitable for driving low impedance speakers like Magnepan 3.6. I listen almost exclusively to classical music and my amp is a class D Rowland 312, which runs cool even in the sweltering summers of Austin. . . I couldn't be happier about its sweetness and its power to deliver staging, imaging, detail, and nuance.

Besides power draw from all class A and some class A/B amps, I would not be terribly concerned about the inherent musicality of any class of operation. You will find musically satisfying amplifiers in class A, A/B, and D alike, and at least as many that will put your teeth on edge -- no matter what their class may be.

Guido
Edwyun is correct, in that my Rowland 7Ms came out of the factory in the late '80s and are still going strong after 2 decades. . . except for the monthly power bill.