I've recently been looking and reading at Audiogon and see that most "High End Amps" are class A. Currently I own a McIntosh C28 preamp and MC2105 amp. To me they sound fabulous.
Would a "High End" class A sound any better?
Of course I realize that there are very expensive class A's that would blow away my Mac's, but what about say a used class A in the $ 1000.00 to $2000.00 price range?
It would be interesting to see how the Symphonic Line ($$$$) vs. a Plinius ($$) would sound side by side. Manual vs automatic transmission.
I wonder if all high bias current amps, or the sliding bias current high current as needed is where that extra sweet audiophile sound is coming from. I am sure it is just part of the mix, but the Plinius looks like one of the least expensive SS choices to get 100 watts of class A power.
Most of you are thinking of 1 type of class-A power amp - the type that Krell, Plinius, Threshold, Forte, Sugden have made/are making. This type of class-A power amp does dissipate a lot of heat as it is biased to run full power bias current all the time. The heatsinks on these amps are large (they have to be!) & the current draw is high thereby running up your electric bill. There is another category of class-A amps that use sliding bias. I believe that Symphonic Line & Karan amps (there might be others but I do not know) fall into this category. These amps run cool when there is no signal or when the signal is low (from my experience I would say when the SPL level at the listener's chair ~9-10' away is in the 80dB range). As you crank up the signal input, the dissipation increases markedly. These amps do not run up your electric bill. Just FYI.
As others have pointed out - a well executed class-AB amp can be very satisfying sonically. I can say this from my own personal experience. However, [b]THERE IS[/b] a certain sweetness to the sound from a class-A amp. I realize that more when I take out the class-A amp & put back the class-AB amp. It's much easier for me to discern what I lost (when I put the class-AB in) than what I gained (when I put the class-A in). In my particular case I say "lost" because I personally like the sweetness of the class-A sonics. YMMV.
Another idea might to get a Plinius SA100, about $1800. They have a switch that goes from AB to pure class A. They put these on the amp to save energy, and then you can flip a switch for "serious" listening. When you flip the switch to class A you start burning 400 watts continuously, nice space heater you have there man.
Most class A amps look to be 25% effecient and have an idle current at 4 times their output. So a 50 watt amp has a 200 watt idle current. The Pass Labs site explains this well. I have not listened to class A, but I think the Plinius could satisfy the curious.
Notice that all Audio Research amps have an idle current at about 4 times rated output, the REF 110 at 100 watts idles at 400 watts, the largest ARC amps like 600 idle at 800 watts. These amps have a really loyal following in terms of their sound, and mixed reviews in terms of reliability.
I have been told that class A amplification simplifies things in that the current is not broken up and then reassembled very fast.
But what does it really sound like? It is expensive and seems to be an audiophile only thing, BEST BUY does not have many class A amps, probably none.
So getting back to Bi-Amping. You could Bi-amp with a low power amp in the mid to get the magic class A sound in the vocal range, and then use SS for bass.
Still another option could be like an ARC VT 50 which is 50 watts and then buy something like a REL powered sub to give you that bass slam. Use the ARC VT 50 with a used set of Maggies to get clarity, transperancy and great mid range and then fill in the bottom with REL. You could do that idea used for $3-4k and have an audiophile set up.
I've long been a fan of 'Class A' sound, specifically from solid state components. I'm a tube fan now, and no SS can compare, IMHO. However, when I look back to my SS days, my favorite amps were Class A amps from Threshold, Clayton, etc.
In your price range, I'd reco an older, used Threshold T200, Forte Model 4a (a real bargain), or the Coda 11.5 currently for sale on AudiogoN.
Hi Scottlanterman, "Consider Bi-Amping" interesting.. personally I was thinking about two different pre-amps, one tube based for vocal jazz and a solid state for rock
Gp_phan, if you can wait and save an additional $1000, and do some bargaining (at the $3000 range) on a used Pass XA30.5, then I know you will get that good Class A sound described in Audiogon. The XA30.5 works well with smaller speakers. It can do the job with some bigger 4-ohm speakers to give them 60 watts/channel, but I would be cautious. People need to do audition before buying anyway. I am not that familiar with other Class A amps beside Pass Lab as they are the lead in this niche market. Perhaps somebody else could help you with the $1000-2000 range. Unfortunately like anything else, you get what you pay for.
Class A is the most linear mode of operation known. But- just like with anything high performance, is the exception rather than the rule, which is to say that AB amplifiers are far more common. On top of that, there can be so many compromises elsewhere in the circuit that they may well obviate the advantage of the class A operation.
Triodes are also the most linear form of amplification known, yet the same caveats apply.
The same goes for fully balanced differential operation, circuit minimalism, etc., etc. When you combine these elements, things tend to lean more in your favor, but execution is still an issue. Cost is a different matter- Class A amps do tend to be more expensive due to the larger power transformers required.
Stanwal's advice is extremely good, and there are amps amps out there that will be a whole new world of resolution compared to the Mac, but not likely for the $$$...
Class A amps will also waste a lot of power and run up your power bill, so be sure it's worth it.
Personally, when the time comes to look at a new amp, I will be looking towards Class D, which is the opposite end of the spectrum in terms of efficiency and value from class A.
Most Class A amps are higher priced, and not necessarily higher end. Due to the high heat output, most class A amp will need higher quality parts and much more expensive case work to dissipate the heat, thus resulting in a higher cost.
Class A amps run at full power when idling. So if you really want a dual use machine (home heater, and amp) then go for pure class A. I have a small 50w 'class A' amp, and love it. I would never buy a big class A because of the heat, and strain on the electrical system.
As Stanwal wisely states, listen before you change. I have owned a McIntosh 2105 for 10 years, and during that time also owned a Mac MC 300 which I sold after 3 years to buy a Pass Labs X250.5. For most efficient speakers, at modest volumes , that amp will run in class A. I used it with 3 different speakers, and for my taste, the Mac 2105 was better in all aspects. The point of course is that you may feel differently, but do not make the mistake that I made and buy on the opinion of others and their taste - try it first.
I do not believe that actually to be the case. As to your question, no , you are unlikely to find an amp that will be unquestionable better than your Mac at that price. You could look at the Pass amps in the 150 range, they will have a different sound than the Mac which you may or may not like better. One of the mistakes most commonly made in audio is to think that you will find an amp that does everything better than the one you have. Unless you have a terrible amp this is almost never the case. Every amp regardless of price is a product of compromises and will possess different virtues. If you like the sound of what you have and it drives your speakers well do not change until you have heard something you like considerably better. I have owned and been a dealer for several class A amps in the past but do not own any now and do not foresee buying any in the future. Class A is not a cure all , it is one technique for achieving good sound, there are others. I would listen to a particular amp regardless of its design and evaluate it on its performance.
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