Best Class A Amp under $2,000 used?

I went with the Pass Labs XA30 but use them for smaller book shelf speakers (KEF 201/2) -not the Dalis.  I absolutely love it.   For the floor standing Dalis (euphonia ms-4), I went with a Modwright 150 SE set up.  

So, have you chosen yet?

This amplifier in the class-A sounds great. https://youtu.be/wMORaaaObCo
http://www.noosfera-amps.ru/en/amps/noosfera-echo-en/ 

I have a pair of Oasis S200 monos
200 watts class A all the way.
Based on the Forsell Statement amp of the late 90s.
probably only worth 2-3k now.

I got hooked and had to add my opinion.  I know the original question was what is best for under $2000, but bear with me me.  I am an electrical engineer, but i am not going to get into anything technical here.  I started out with tube amplifiers.  I grew up in that time when everyone wanted to get rid of their tube amplifiers and get the new better sounding transistor systems.  As a poor teenager, i bought used tube equipment for cheap (this was the 70's)  I just recognized it sounded good and was cheap.  So that was my basis, I just wish I realized how valuable my Fisher 800C with wood case would become.  The Fisher broke and was replaced by a unfulfilling solid state pioneer amp.  I then acquired a  pair of  Heathkit tube WM5 mono-blocks.   Being an electrical engineer I wanted to move forward into present transistor technology and wanted to stop dinking with tubes.  I listened and listened, and finally settled on a PS audio 200C, it sounded great but build quality was not that great (I lusted after krell build quality, but the Krell class AB which I could afford didn't sound that good) ).  I then found my present class A amplifier, which I think is one of the best sounding budget SS amps I have heard, the Forte 1A a 50 WPC class A amplifier.  This amp does 100W at 4 ohm and 200W at 2 ohm.  It was not designed by Nelson Pass, but came out of his organization and is very minimalist and just as well is his design.

Your speakers are 4 ohm, so with a Forte 1A you will get 100W which should be more than enough for your 88 db/w speakers.  you can find a Forte 1A for ~$500, I liked mine so much, I bought a spare for backup. 

So I think you are on target looking for a class A amp.  Generally it is easier to build a good sounding class A amplifier than a good sounding class AB amplifier so my suggestion is to buy anything that is  pure class A >100W @ 4 ohms and you can't go wrong. 

Just be aware, some of these amps are going on 30 years old, and will be needing to be rebuilt.  My Caps were still good, but I had to replace all the trim pots due to wear/instability.


    

It's pretty clear that the original poster has no idea what he's doing. But for the others:

Yamaha B-1. 1975-1978. Caused Levinson, Pass, and others to dream into the future. 150 watts pure and only Class A into 8 ohms at .1% distortion, more than 250 watts at 1% clipping criteria. Nearly doubled down like a perfect voltage source ( 4 ohms ~ 500 watts at clipping) . Mega SIT VFET's, super quick with 72 nanosecond rise time. I've seen a few sell for $2k or so but often need work. 

Very rare. Only about 50 made, I had a couple and wish I had never sold them. Specified as 4-16 ohm load capable, but I successfully drove the original Martin Logan CLX prototype- which was nearly impossible and only one cut above a short circuit (production models were tamed down considerably but never sounded as good). Also superb on Stax ELS-8x's, another rare and difficult speaker needing lots of power and load stability.

Issue here is if you blow a SIT, they aren't available anymore. New SIT's manufactured by Digital Do Main out of Tokoyo might work, but I don't know if you can buy them.    osobagary@gmail.com

There's a Plinius SA250 mk. IV for sale here now near your price range.  250W class A power and has a switch between A/AB operation so can operate at higher efficiency and less hot for non-critical listening.  Best of luck. 

Get a pair of clean efficient speakers and a good single ended tube amp as I recently did, and stop chasing watts…my current rig sounds better than anything I’ve had in my home in over 50 years of audio fun…it’s simply funner, and more dynamic somehow (everything I knew is wrong?). Watts SCHMATTS! Note I use a couple of powered REL subs for "under 40hz" duties so maybe I’m cheating a little…still…great sounding, more musical, and, dare I say, more realistic, is just a better thing to have as it’s better. Or as Hawaiians say, Mo Bettah.

Sony TA-A1es integrated. 

I had a Forte 4A class A amp. Forte was built by Threshold. 50 wpc into 8 ohms and 100wpc into 4 ohms. All in Class A. They could handle Thiel 2.3's which I had at the time. When on the market they get scooped up quickly.

Sorry, I missed seeing the first part of your post! Dali's/Wadia is a good speaker/source combination! I still recommend a SET tube amp (even one using 300B tubes). Very smooth and yet detailed enough to hear all the nuances in your favorite recordings!

Average listening uses only a few watts.   I recommend a single end triode (SET) amp using 211 or 845 output tubes for 12 to 15 watts of pure class A power.        By the way, you did not list your speakers. Amplifier/speaker matching is important! Same for your signal source: analog or digital? 

you wont get 250w classA anywhere. push a bit your budget if possible and get the Benchmark AHB2.  It plays well above its price and is a near perfect audio tool. You will have everything you will need amp wise for the next 15 years.

Yes.  I have seen a couple of discussions on the forum about that subject.  A good point. I could see how certain sounds can bring you to memories of how things should sound vs how they actually sound.  As I wasn't privy to owning very good sound systems as a teenager or young adult, I might not be as inherently partial to legacy equipment.  Maybe I would be better off getting hooked on the new technology if it is superior based on the latest testing equipment.  Does anyone care to recommend which amp companies are on the cutting edge of newer technology with in reasonable budgets?  (Whether you like it or not)

I guess he is saying we like a certain sound or sonic we came to appreciate when we were younger and still want it despite advances in technology.  It is true, we like what we like and want that, as do many in our age group (boomers)  or cohort, which creates the demand against which supply or build costs, leads to the prices we are willing to pay.

Something closer to a Pareto curve.  Its a surface, not a point.  Amplifiers are systems-of-systems.  Transformer technology has evolved.  Discrete components are no longer +/- 5%.  Some are now chip-ed assemblies rather than PC boards. And line widths are under 10 nm with the upper end of 80 nm dissipating from stocks.  Speakers have changed. Test equipment has evolved.  Recording and mixing technology changed (evolved, arguably).  You have devices now that clock in nano (soon to femto) and a few 10s of milliseconds vs micro and hundreds of milliseconds. RIAA curve has evolved. FCC and CISPR measures and isolation have changed. There are some who find comfort in what they once knew. Economic market value isn't just set by taxonomy- alone or in large part.  Authenticity is now argued with newer, non-deterministic math. Still, some cling to subjectives in prose and poetry to evoke a consensus. Market valuations are just a sum of demand against a supply.  Baby boomers will still prefer a signature sound they have trained themselves listen for. Greenspan's 'irrational exuberance'.   

@sumwhat  Are you saying there is (less than optimal) legacy equipment available at some price points while (optimal) legacy equipment at perhaps higher price points ?


"As the components, and various engineering trade-offs, of legacy systems become rare- available inventory inelasticity changes the value...non-linearly.   This all works against you."

You might start with Audio Bluebook on this site.  See what's in the market.   https://bluebook.audiogon.com
The triodes (valves) plus Class A power supply appears preconception more than a criteria which assures a quality experience. 
Unreasonable constraints elevating legacy technology (& sub-optimizations) works against you, not for you.  There is a point in the used market where you are just buying someone else out of their boat anchor.  This is business built on scale.  As the components, and various engineering trade-offs, of legacy systems become rare- available inventory inelasticity changes the value...non-linearly.   This all works against you.  Still- "may the odds be ever in your favor", though. 

Thank You for all of the feedback and recommendations on these questions.  I am going to take a few days to look some of these amps up.  I wish I could sit in a room, listen and compare them over a couple of days but I get a feeling that is not going to happen (ha)

Interesting @lowtubes that the older amps can still hang with more modern technology. I like the idea of a professionally refurbished older amp because some of them have a great cosmetic appeal as well.  The Belles SA-100 and most Pass amps have a great look to them as well.  About 20% of my choice would be based on this ( especially since I can't hear them). 

@Phusis -Thanks for the well written piece.  I didn't know that some of the better D amps draw comparisons/characteristics of class A.  Nothing wrong with liquidity.  I have a Peachtree Grand which is ICE and nice but I find it sort of lacking bite and texture at lower volume levels.  

One thing I didn't mention is that my Kenwood 700 M & Wadia Dac 321 is in a smaller carpeted room and the Grand system is in a larger room with a tiled floor.  The larger room does have a rug, furniture and broad band sound panels.  I will have to do an amp switch to make sure it's not the room vs the amps.  

There's also the Bryston 4B series that fall within your budget and power requirements

+1 @nordicnorm

I have no idea why people here don't just answer your question. There are a few very good class A amps to chose from. The best under $2,000 used?  That's a hard question to answer because there is no best. It all depends on what kind of sound you are looking for. If you want a very detailed sound, try the older Krells, want a more musical sound, Thresholds, and if you like something in between, Mark Levinson. These older amps are still killer machines and would still be fine in a system today. I didn't put specific models because there is lots to chose from, so do your research on which model you like most. Good Luck!!!!!

Perreaux PMF 1850. 170 watts of Mosfet power..  can't be beat for sound quality and will cost less than $1000.00. 

...he's not listening.

Might I suggest a different direction? 1) a pair of Crown PS-400s. ($700-$800 used) Heavily biased into class A, plenty of power,excellent specs,bullet-proof build quality, and sound pretty darn good! A Crown Macro or Studio Reference these got an A rating for sound quality from TAS,Stereophile and other audio mags, unreal power 760wpc-8ohms,1,100wpc-4ohms !
($1100-$1500 used) Best of all but hard to find for your price. Any of Jeff Rowland,s bigger amps.  They all sound great!

if you can find them NRG A400 will give you what you want not sure if you could get them under 2k, I don't know anything that can touch them.

Class A does often sound very good - I used Classe DR3 VHC which with 45 watts will drive low efficiency speakers like Apogee Scintillas, and Belles A.

I don't think you will find, nor need anything like the Class A power you are asking for to drive just about any speaker out there.  You'd be amazed what amps that are well under 100 watts in true class A can do - but you may want to consider that they are running all the time, putting out anything not used in amplifying signal as heat. In one system I run a pair of DR3 VHCs and in summer it gets pretty darned hot in there.

Others made pure Class A amps of modest output - Electrocompaniet, Bedini, and they would drive the heck out of very difficult loads. 

For $2k you should be able to pick up some A/B amps with sturdy power supplies that will give very good sound - if you were closer, I'd offer you a Rowland I have for sale!

Listen to a Parasound Halo. They're very good for the price. 
By coincidence, I have one for sale. 

OK, here is a pair of Bryston 7B-ST monoblocks that are slightly above your budget ($2,600):
http://www.usaudiomart.com/details/649345505-bryston-7bst-amplifier-pair-two-for-sale-as-set-only/

- 800 watts per channel with 1 or 4 Ω load
- 500 watts per channel with 2 or 8 Ω load 
- parts and labor warranty until February 2020  
- switchable between balanced XLR or unbalanced RCA inputs

These puppies will drive pretty much anything!

What is a better amp/ deal:

The Threshold 350e mentioned in the above thread or this Pass x 3 amp with link below?

http://www.usaudiomart.com/details/649340044-pass-labs-x3-150w-x3/?utm_campaign=new-watchlist-added&...

puffbojie --

I’m inclined to reiterate: where does your favoritism for Class A designs come from - is it first hand experience with particular pure(?) Class A amplifiers, or is it more like the mere thought of what Class A is said to represent a la, say, a smooth, liquid, warmish, open and effortless imprinting? I’m just trying to get a bearing on your sonic "inkling."

Going by more traditional Class A/B solid state designs perhaps I’d be looking for a used Belles SA-100, if they’re even around (but don’t count out the pure Class A SA-30, which is much more powerful than its 30 watt rating would indicate), the integrated Belles Aria (which can be had new within your budget), as well as amps from Symphonic Line or Modwright. I believe any of these options represent a relatively authentic, smooth, dynamic and coherent sound, and seem to have a sturdy, no nonsense build quality and topology use.

Maybe I’d consider some Class D alternatives as well, like a (used) Devialet 120 or NuPrime ST-10 and the integrated NuPrime IDA-16 (including DAC) - the latter two of which can be had new within your budget. To my ears Class D designs sometimes exhibit a smoothness and liquidity one associates with pure Class A designs, though without attaining quite the same degree of texture, reverberate capabilities and overall naturalness. My main gripe with some Class D amps (not that this is necessarily representative of Class D sound) has been a slightly too polished and processed feel to the sound - even "filtered." Still, there’re very good options here as well.

Pass Labs has received a favorable mention here, and while they're no doubt highly resolved and "sophisticated" sounding, very high quality amps I've found them sonically to be too well behaved and on the verge of being boring. Indeed very much "hi-fi," but less like "live" sound. Just my 2 cents..

Sorry for the confusion.  I think my speakers require too much power for me to consider a pure Class A that I could afford.   I like the sound of the Kenwood 700 M over my Peachtree Grand (ICE Power) so was going to move to solid state / with DAC for the living room.   Phusis info was very good.  I'm totally Ok with A/AB designs.  If an amp can drive the speakers at class A for the first 20% or so I am totally ok with that.  Basically what would you look at with 2-3k budget on used market? 

puffbojie --

What’s the reason for your inkling towards class A amplifiers? I’m not trying to discourage you, but going for a pure class A amp (i.e.: which rules out high bias or class A to A/B shift designs) - with the potential and worthwhile sonic advantages they carry - within a limited budget and high wattage requirement is nigh on mutually exclusive. It seems to me there’re a lot of "class A" designs labeled as such which really aren’t, and in case you’re intend on pursuing true, pure class A I’d say stick with what is really that (and forget about 100+ watts, let alone >50 watts), or go with any other design that isn’t strictly class A and stop thinking about them as anything other.

Largely I believe it’s a marketing ploy to boast class A capabilities which really aren’t (instead pseudo this and that), not least connecting them with high wattage specifications - a combination that’s supposed to sell as an audiophile’s (sonic) wet dream. There are likely class A/B designs out there that, while they wouldn’t claim to be anything other than class A/B can have sonic traits that go closer to pure class A designs than those designs that flaunt class A "to some extend."

A number of “tricks” have been used to claim both high power and Pure Class A. While it is perfectly OK to bias an amplifier into partial Class A while allowing additional power for short term transient headroom often this is done without declaring the true operating parameters. Commonly the amplifier is claimed to be “Pure” Class A, and yet only delivers Class A performance up to a percentage of its output power. Other schemes have been invented that cause the amplifier to vary its Class A operation depending on how loud the music is. The idea being that it only runs in Class A to as high a power as needed moment to moment, and thence avoids the heat. This causes the music to modulate the amplifier’s design parameters, and in turn introduces other forms of distortion.

http://www.pureaudio.co.nz/?page_id=165

To my mind it’s about being honest with the design a manufacturer is going after, and call it by its right name. I’m aware that where class A to a limited extend (i.e.: pseudo) is more or less (usually less) openly declared is to inform the potential buyer what may be inherent to the design, but it’s still trying to sell a trait that in its diminished state may have marginal effect among many other design decisions, or even severe compromises.

If anything I’d go after designs that are topologically simply and "no nonsense," and if you’re still going after pure class A I’d have a keen eye on what really is and what isn’t (and lower your wattage expectations to no more than 30-40 watts). From personal experience I can recommend the pure class A amplifier Belles SA-30 (30 watts), but its class A/B sibling SA-100 is said to be sonically very close. I can imagine those can be had used in the $3k range.

Sumo made some pure Class A amps,  but none of the power rating discussed here.  I believe 3 different designers....
Sumo The Nine and The Gold  60 watts and 100 watts by Jim Bonjiorno
Sumo Nine Plus updated from Nine by Rich May 65 watts (Nine is Better)
Sumo The Ten by Jason Stoddard  100 watts

A  Pass labs f6  50wpc into 4 ohms it has a but of Sevreal flavors Jensen transformer inputs, to a Fet stage,  then mosfets all pure class A . 

Most folks around here know that the boys at Coda were Threshold designer engineers... Threshold is the company that Nelson Pass sold before starting Pass Labs... The Coda stuff definitely has the Pass characteristics and run very high levels of Class A.  You can occasionally find a few of their amps in your price range.

I had no idea most class A type amps switch into alternate AB power after a set threshold. This is really cool though.  Just looking for advice on a great solid state choice in the 2k -  3k range.  So far Pass designs are king.  Let me know if there are any others. Bryston??  

Why did you want pure class A.  As all have said most amps are high biased to hold in class A until a threshold wattage requirement is surpassed then it operates in A/B. I have never been sure of when Class A resumes during a peak then drop .   I owned Klipsch Palladium 1Ks which were biased to class  A for 125 watts.  I never knew when it changed.  *not a great amp anyway!

Interesting  - thanks!  

That Threshold "e" series was the last Nelson Pass design at Threshold. Also, the recent work on the amp was done by Jon Soderberg. He worked for Nelson Pass at Threshold, so there is no better Threshold tech anywhere.

Part of my inspiration to move to solid state was a purchase of a Kenwood 700 M which I think sounds amazing compared to my ICE powered amp. I figured a modern solid state version would be even better.  The Threshold looks nice.

With regards to Glennewdick's comment -  
What about the more vintage class A power amps such as Acuphase or Luxman?  Which models were you thinking?  

What about 70's power amps like Marantz, Sansui or Pioneer?  Are these considered garbage sounding vs the modern age or are they comparable? 

For 250 watts of pure class A, a pair of Threshold SA/12e’s would definitely work, however if you find a pair, they would be well above $2000. Here’s a nice Threshold within your budget,

http://www.usaudiomart.com/details/649302974-threshold-s350-power-amplifier/

This amp could also be changed to pure class A, but only at 60w/ch. You would need to send it back to Jon Soderberg of Vintage Amp Repair.

Regarding amps mentioned, I tried Pass Aleph 0`s with Martin Logan Quests and they did not drive them well.  The Class'e CA-300 did fine, but not strictly class A.

don't forget the Acuphase's and Luxmans that were pure class A many out there for under $2000 now.

" I like the Pass Aleph 5 class a at 60w and those are below $2000 and should work great with your Dalis."

After reading that, I just wanted to update my post. An odd thing about the Aleph series is how they rate the 0s that I recommended above, and the 5. The 5's are 60 wpc and the 0s is 40 wpc (Not to be confused with the 0's which are the mono versions of the 0s's. 80 watts per mono).

The 0s is a much bigger, costly and more powerful amp than the 5. I have no idea why they would rate it for less power. Its just something to be aware of.