Class A or A/B amps

Interesting. Thanks!

 

+1 for Plinius....

 

+ another for Plinius!

 

I bet they do sound great. At $60K for Class A/B amps...it's kind of a tough pill to swallow given the Class A selections in that price range and some for a lot less.

 

They went up to $60k? Last time I heard they were around $45k.

Anyway, good point. But, if you want high end Class-A, you'll have to pony up. Such is the price of admission.

However, the D'Agostino amps are pretty incredible. Listen and you'll find out what Geoff and I mean.

 

I thought the DAgostino amps were class A... Agreed they did sound good.

 

I am happy with my A/B amps. I have not heard a PURE class A, However. I think I would need a somewhat powerful(high current)amp for my speakers.

 

Yep, they sure did. Will you be reviewing them?

 

Just off the top of my head, Accuphase or Pass Labs would fit the bill. Both "double down" (double the power) as the impedance gets lower. For example, an Accuphase A-65 puts out 60 W into 8 Ohms, 120 into 4 Ohms, and so on and so forth.

http://www.accuphase.com/cat/a-65_e.pdf

 

Prefer class A. A well built SET amp just seems to have a wonderfully natural symmetry with high efficient speakers. Select OTL's (Atma-sphere) and push-pull (Shindo) amps have also worked very well in my system but the success rates of these topologies have been more mixed. While I've tried several SS amps with my system I have not been impressed enough to buy any.

 

That's cool...but did you try Class A solid state?

 

I'd think that all amps should double down. It's physics. If you have an amp that is putting out 25 watts into an 8 ohm load and you change the load to 4 ohms, it will have no choice but to try and put out 50 watts.

Of course this can only happen if the amp has enough power supply to provide the current that is needed when doubling the load. In addition, the output devices have to be able to handle that additional current.

If the devices can't handle the current, they'll pop open. If the power supply can't, then it's voltage will drop. If it's voltage drops, then so does the output power of the amp.

Also realize that most of these amp ratings are at maximum output power. At lower power levels most amps should double down. At maximum power, the supply usually becomes quite a limiting factor.

 

My prior amp (Forte'4a) was a 50 watt/channel class A amp. It was small but ran hot like a space heater. Leaving it on 24/7 cost an extra $10 a month just for the amp, on my electric bill back in the 1990's.
I sold it when i bought a better sounding Bryston 4B-SST2. Which runs the first 5% of 300watts in class A .
It runs cooler than the Forte' did, though it is three times the size, and over twice the weight.
And I mentioned the Bryston sounds better... It should, at three times the original price of the Forte.

 

Ok, cool, thanks for the info!

 

I have the older 4BSST model...Bryston is very good when it comes to A/B amps, imo.

 

Thanks for that, but I am fine as is with the Marantz MA9S2 mono blocks. They seem to be doing quite well and I will not be making any changes to those for a while.

 

Well, you're welcome, and if I had those, I wouldn't change anytime soon either!

 

If your talking flat out pure class A I'd take a Pass Aleph Single ended Mosfet amp, which was one of the better solid state amps I used, but you can fry an egg on the thing. No solid state class A/B amp I've heard can quite match a good class A design in reproducing the timbre of instruments. Most designers say class A is the best sounding topology, but the design has too many drawbacks- energy waste, excessive heat, usually lower life of the internal components because they have higher heat stress. After 2 years with my Pass, and sometimes sweating during listening, having the AC go on much more often, in addition to the higher draw of the amp itself, it became as much about practical considerations and listening comfort than sound quality (I reached similar decisions with tube amps). I now use a class "AB1" amp, a design that is biased a little stronger into class A but doesnt run like a toaster oven- The Rega Elicit. I can hear where it doesnt have quite the quality of a pure class A, but it is well up to scratch for my needs

 

Yes, pure Class A. I understand the drawbacks, but it's worth it to me, and I believe many others?

I guess there's no such thing as a perfect amp.

 

Right Dave, no perfect amp I even tried class "D" (no luck there). And yes for some class A is worth it. It's a personal decision for each of us- the factors for me were energy/ethical considerations, listening comfort, cost of use, and asking myself if I was being subserviant to equipment (and answered yes). I could'nt justify it.

 

I see. Well, I agree with you, and I guess that's why there's so many different amps on the market. One can't possibly hear all of them!

 

When did D'Agostino sell his Krell? I wonder if the current owner will run the company into the ground in much the same way Carver was run into the ground after Bob Carver sold his company ...

 

Simaudio amplifiers "double down" as well - for the record. They specify Class A for 5 watts.

 

They're not pure Class A, though.

 

I believe he (Dan) was forced out of the company. I dunno, we'll see on the rest.