I can design a horrendous class whatever amp too. That's not the point. No, design is a lot but it is not everything. There are limits of what is possible. Orpheus10, there are great SS preamps, they are expensive and one can probably do better with tubes for the same or less but I don't know it. Boulder, Gryphon, D'Agostino, Soulution, Accuphase etc.
... as already noted, because it does not always sound better. I can easily design a horrendous class-A amplifier. Design is everything. All the practical benefits are noted as well, but i can further assure you that the cost (transformer, devices, heat sinks, etc.) of a pure class-A amp consumes resources that could be better spent on sound quality elsewhere.
While I don't feel strongly enough about class A vs AB to become a television evangelist so I could spend a few billion to hire the Islamic State tosteal for me a Tzar Bomba to use against people using AB amps, I make my own class A tube amps because they are simpler to build and you can for a few hundred dollars buy parts as good or better that what you get if you spend five figures on a high end tube amp. I like my Magnepan speakers so I solve the sensitivity issue by using radio station transmitter tubes. If I use 45s by themselves I have to use sensitive speakers.But I have heard some fine sounding AB amps too.
Inna, some people can hear better than others in regard to Class A.
In regard to SS versus tubes, some people are music lovers, and some people are equipment lovers.
When I had an audiophile music loving friend, we swore by our "0 distortion" SS gear. I requested a CJ preamp to audition at my home, and invited my friend over for his evaluation.
The CJ was a loaner and produced apparent distortion, but even through this distortion, we both agreed that the music sounded better. Neither one of us has ever considered SS preamps, since.
However, an SS power amp simply reproduces the signal of the preamp; consequently, a high quality SS power amp is acceptable.
Dan D’Agostino's son Bret certainly agreed with your premise & his co. Bully Sound still has their site up even after his demise so presumably they're some kind of going concern > https://bscaudio.com/Pages/aboutHistory.php
As someone who earned a living as an electronics technician, I am qualified to state what is "theoretically" better. While Class A is theoretically better, you need the hearing of a good hound dog to tell the difference between AB and A; maybe some young people got it, but I'm very doubtful about old folks.
What some old folks got is "deep pockets": deep enough to entertain their fantasies.
If I was rich, I would still have high quality AB, because I'm certain I can not hear the difference, so why pay so much just to heat the house.
One has to take the time ( as little as absolutely necessary) to pause and reflect on the reality that written or spoken opinions are largely driven by the insatiable need to be acknowledged.
Orpheus10, I would say that tube phono stage is most important. SS class A line level preamp and class A power amp can be quite acceptable, at least. Most people, if not all, do prefer class A amps and integrated amps from the same company, be it Accuphase or Luxman or Pass.
My buddy has Klipschorn corner speakers. He runs them with CJ premier mono block tube amps. So tonight I brought over an old class A stereo amp my partner put together with some old parts we had laying around. 1.5wpc 45 tube pure class A. Needless to day the Class A walked all over the CJs. It was not even close - better everything including more bass and deeper bass output from 1.5 watts. Music just poured out of the system, tone and space was killer, wide open musical sound. So dynamic and delicate at the same time. I may have to get some horn speakers now!
Why would anyone prefer anything besides Audio Research monoblock tube amps, when they are so awesome? For only $70,000, plus a 5 ton A/C unit to cool it, you could begin building a truly great system. All you need, besides the above, is a $10,000-20,000 preamp, a stupidly expensive source or three, and a room to put it in. Then, you could chase away all of your friends by showing them the intracacies of minute passages of music that really show it off. I prefer the Class A Audire Monarch towers, and a Diffet 5, but settle for a trio of Audire Fortes (Plus two Audire Diffet 3 preamps), and really love my music, even when listening to Jazz 67 on XM, despite its inferior sound. Why would anyone prefer a beautiful Ferrari to a Bugatti, when the latter is faster? Why would anyone prefer a wife of fifty years, when a Russian model is cuter?
I say it again. If they can take it without strain on anything, those same A/B amps will sound even better again if their Class-A bias was turned up full, as you eliminate any xover distortion, as it never goes into Class-B which gives xover distortion no matter how well designed
We talk, but are we communicating; some people have equipment to hear music, while others have music to hear equipment. Which camp do you fall in?
If one is an obsessive music lover SS preamps never sound quite right, however, obsessive equipment lovers claim tubes give distortion.
I think tubes versus SS is more profound than Class A, AB. Personally, I would not want SS preamp no matter what class or how expensive, SS power amps are OK when necessary. Could not stand ARC preamps that were SS, I don't know if they still make any SS preamps?
While theoretically class A is better, given same quality of parts and craftsmanship, I'm sure there are few people who could pass a blindfold test to distinguish which was which.
It’s not true it’s not that cut and dry many very high quality amps may have the 1st watts say 20:watts in pure class A then switches to class AB. That being said , inside the Quality of the parts have much more to do with the final result of the sound . I owned a Audio store until 09 and Had many parts modded or upgraded,for the vast majority of mfgs use average parts at best . on average 25% or less of the cost actually goes into the electronics,the rest over head and markup. That's how Modwright was able to be so successful by putting in Premium parts in the most critical areas. Companies like Gryphon for example use top of the line puts throughout ,and are exceptional in sound quality. That being said ,not everything is in black and white. As well as the engineering and their design .
Gato Audio, a Swedish company makes AB amps that will compete with almost any class A amp. They now sell factory direct with free shipping. And best of all no sales tax. Steve Guttenberg did a review recently.
Class A sound better? No, lots of factors to consider. You have first of all assumed Class A sounds better. Not always true.
Exactly. I own four Class A amps so obviously like what they offer (aside from the heat and the electric bill), but horses for courses - some Class AB amps sound better in some systems. Generalizations like the original posts are meant to stir fuss, not logical response.
I use a Class AB tube amp in my main system as a matter of fact, and I prefer it with those speakers to the 100 lb. + Class A monos I used to use. OTOH I use a stereo Class A amp with some electrostatics and it is a great match. YMMV
Broadly speaking, there are often a lot of other design variables between two SS amps beyond just the bias level of the transistors. A lot of the high end Class A amps are designed to have very little feedback, which enhances the high linear accuracy of Class A, but often at the expense of slightly higher noise and lower damping factors. That tends to create a certain sound which I personally feel is a bit closer to the typical tube sound. On the flip side, it is more common for the Class AB amp designers to use some amount of local and global feedback, which "can" marginally impact the linearity, while reducing noise and increasing the damping factors and tightening the bass. In my experience, it is very hard to generalize that Class A sounds better than Class AB since there are a bunch of other design factors that have to be considered. The typical Class A amp may sound different than the typical Class AB amp, but it's not always better...
Class A operation is integral to the performance in this case, and it
is worthwhile to explore why. The primary virtue of class A lies in the
smooth characteristics of its operating parameters. The gain transistors
are operated in their linear region only, where the distortions are
limited to smooth, simple forms, unlike the abrupt distortions created
when the transistors in class B output stages switch on and off."
I've built a couple of his DIY Class A projects. They are exceptionally good sounding amps. Why not class A? Cost (especially cost/watt ratio), Heat and nothing else unless you're a greenie. In that case, power consumption.
There is a REAL difference in the functionality of a class A vs anything that has to "turn off" one transistor and "turn on" another one at every wave form. Just considering that it is between difficult to impossible to match those components and operate them outside of their linear reigons. Then you get into negative feedback loops to correct the crossover wave distortion, adding additional complications and additional distortion opportunities. My best example is I've owned a high-end Oddyssey amp that had a billion components in it and costs a ton. My DIY F5 Pass/First Watt amp absolutely blows it out of the water, sound-wise. There are compromises, but I sincerely believe the difference between the functionality of Class A vs class B circuit is obvious and significant.
"As a direct example, some feel that the Luxman 509X class AB at $9.5k sounds better than the Luxman 590axii class A at $9k. Can’t get much more absolute-busting than that. Same company, both integrateds with same features, essentially same price, both current products." ===
I thought that too (and I own the L-509X), but did you know the L-509X is both A and A/B? It delivers the first 6 watts as "pure" Class A then transitions to A/B for the rest of its rated output.
I confirmed this with Luxman USA during a discussion of the L-550 (which is also a hybrid A, A/B, not just A)
Quote from Luxman USA email
...The Luxman L-509x is an excellent amplifier. It is considered “top of the line” and most recently introduced Luxman integrated amplifier model. It features circuit and construction details/refinements not present in (earlier introduced) the L-550aXII and L-590aXII.
L-509x is biased such that the class-A operational envelop approaches 6 watts/channel into an 8 ohms resistive load. At lower (or higher impedances) class-A operation transitions to class AB at lower output. (i.e. near 3 watts/4 ohms resistive load)
Hello. Interesting debate. I’m in the market for integrated amp to pair with my Goldenear Triton 2+ speakers. In the next couple of weeks I want to demo Pass Labs Int-25, McIntosh Ma-352, Luxman 509/507 590/550 depends what dealer will have in stock and maybe even Arcam Sa30(first 20w in class A) I don’t care about measurements or numbers,all I want to hear is beautiful music. I rarely go over 85db in my medium size room so I think any of those can do that. A,A/B,G.One of them will win. Cheers
Reading all of the responses from a simpleton’s point of view is very interesting. But the ultimate measure for any piece of hardware is the one thing that’s totally unique for each person. How their complex inner ear relays information into the brain, which works out what’s pleasing to the listener. Not to mention the endless variables that change our hearing over time. You can’t tell someone there wrong when you don’t have their ear and brain. Never mind the biases we have from where and when we were raised
Hi, I compared the sansui AU-777A and sugden A21, i preferred Sansui, and my best integrate amp is Sony ta-5650, really better than two amps. The sound of the Sony is the same than pass first watt SIT (V-fet transistors), the new name is SIT.
I might be off here, but class A amps don’t drive lower impedance
speakers very well either. Most class A amps aren’t stable into 2 ohm
loads. Krell being one Of the exceptions.
The class of operation has nothing to do with what load impedance the amp can drive. They simply aren't related, plain and simple.
S’funny, one of the nicest class A amps I have heard is a positively antiquated JLH69. It can really sing with a pair of heritage Klipsch’s. There is something fundamentally ‘right’ about its sound that a lot of more modern amps fail to grasp. AB can sound great too. All depends on the implementation.
Really depends on the speaker in my experience. Went with the class A few esoteric 30 watts in my smaller room during a demo of a speaker I desired. Made a deal for the speakers and demo amp. Despite my current speaker 8 ohm 92 dB sensitivity the combo is awful. Still waiting for speakers to arrive From Scotland
I might be off here, but class A amps don’t drive lower impedance speakers very well either. Most class A amps aren’t stable into 2 ohm loads. Krell being one Of the exceptions.
I might be off here, but class A amps don’t drive lower impedance speakers very well either. Most class A amps aren’t stable into 2 ohm loads. Krell being one Of the exceptions.
Just buy whatever sounds best to you.. Glad we have choices.. I will stick with Class A amps as they provide the best sound to my ears. I agree with @atmasphere , The topology is simpler, but requires a better PS and ways to manage heat. Those who buy based on efficiency alone are missing out..
Although Class D is the first amplifier topology that theoretically offers completely linear operation with 0% distortion and no power loss at 100% power efficiency, the commercialization of Class D audio amplifiers had to wait until the ‘90s when silicon (Si) MOSFETs with sufficiently good device parameters became widely available.
As a casual listening “semi-audiophile,” my journey took a delightful turn when I started digging through the story of the early Crown SS pro audio amps. I ended up scoring two PS 200s in decent shape for under $200 each, sent them back to them back to the Midwest for refreshing and thoroughly enjoyed building two different systems...a 6U rack system with modern processing and vintage Cerwin Vega/Jensen sub speaker combo...and the other a “rat rod” rig with nothing but an unpowered Shitt preamp and BT2 Bluetooth DAC with modern REL T5I sub and Onkyo towers both running off high output.
We don’t play much volume around our home and cottage, so these venerable refurbished 90W Class A/AB/A+AB Crowns, both removed from churches, run in crisp Class A most of the time and present a surprising snd pleasing sound stage. Great fun and great value in the final analysis, FWIW
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