Amp improvement since 1994?

How much real improvement in top level amps. Where have the gains been?
Interesting question as designing and building a circuit to amplify an audio signal is a fairly simple task. While there have been improvements in parts available as well as improvements in getting amps to react with different speaker designs, the basic principles haven't changed.

Many audiophiles prefer amps designed and built in the 50s and 60s so we know it has been done well for years. I'm interested to see what others have to say.
digital amps widely used in audiophile applicaions.
I would say the transparency has took a step up with modern amps from 2000 to 2014, real old amps to me sound like very old out dated speakers compaired to any speaker from 1992 to present.
It depends on what you mean by "real" improvement. Probably nothing that can be measured.
I do agree that the trend seems to be towards transparency/resolution and away from musicality, but I'm not sure that is a good thing. My old tube amp beats most of the modern amps out there now, IMHO.

As to your last question, where the gains have been, I would suggest mostly in the price tag.
Interesting Timrhu. Audiolabrinth, I realized dramatic transparency improvements from power supply improvements. Experimenting with balanced isolation transformers, various conditioning devices and MIT networked power cables has improved my preamp (reputed to have a 'very' high quality separate power supply)incredibly. I believe the power supply was definitely the weakest link in my system.
Look at power supplies in the newest Rowland amps - they are line and load regulated high frequency (1MHz) switchers that are extremely quiet. For that reason he uses switchers in preamps (where efficiency plays no role) - instead of linear power supplies, that in reality are noisy unregulated primitive switchers (but easy to design).
Plenty of improvements
Take Pass Labs for example. The new supersymmetry is amazing!
Real designers are constantly pushing the edge of what is possible.
Yes, plenty.

Smaller, lighter, more efficient, more power, lower noise levels, more compliante, you name it, improvements pretty much in every way. Technology moves ahead significantly in all ways in 20 years.
The better amps of today are better, but, much more expensive than 20 years ago.

The average amps of today are as good, as the above average amps of 20 years ago and still in reach of the average audiophile today, but twice as expensive.

Inflation in the price of all amps, because most all mass produced, foreign made, amps are gone! Small companies can only make money selling a few expensive high profit margin amps.

The audiophile market has gone to the rich, and shrunk for the average audiophile who mostly buys used!
Parts quality is way better -- especially capacitors. But everything helps (resistors, hookup wire, volume controls, connectors, etc). And some of the new transistors are awesome, though the low volume of hi-fi leads to a lot of discontinued pieces of otherwise great silicon.

The further pursuit/emphasis on the "all out assault" side has driven the creation of some crazy (and interesting/awesome) high power units in each particular topology (e.g look at VTL's and VAC's top tube beasts, but also some of the crazy SET implementations) -- but that's basically an extension of "we have a huge budget so we can throw more hardware at the problem to get better performance". And very few can afford that. Computerized tube bias schemes too, I guess.

It seems that a few very bright folks have been pushing audio circuit designs forward (e.g. Nelson Pass, Kevin Gilmore), but elsewhere most products just seem like rehashes/remixes of ancient ideas (and not always done well, either). Or even original but really bad ideas.

That's why for budget-fi it's hard to beat the satisfaction of a good vintage tube amp rebuilt properly with quality modern parts (e.g. a pair of Heathkit W5 monos will turn out very very nice!).
Mapman, how significantly? This is a question I'm very interested in as I'm a vintage guy. The only current prod. receiver I have is the dedicated HT cheapo Yamaha that I don't even know the model of nor do I care. I'd have to check if it's even a Yamaha but I won't bother. Fwiw, it sounds capable.
it seems evident that good SS amps have gotten better, and do not sound quite as harsh as they used to; but what about tube amps? Have they really "improved"?
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I would say...accessablity to quality tube amps (rogue for example) . Hybrid tube and SS. and alos refinement and acessablity of quality SS as well.

Of course,there is no exact answer. But there are many very high quality amps out there from many reputable companies that leverage various technical advances available these days not available 20 years ago. The best general example of progress in amp technology in ercent years is Class D amps that are up to the task of truly bringing out the best in smaller full range less efficient speakers, that years ago required large heavy monster amps that most would not have wanted to deal with, even if they could afford them. Nowadays, there is no reason one cannot find an amp capable of driving most any speaker to their maximum potential with just a modest investment. 250w/ch to 8 ohms or more is often NOT overkill for best results.
You can finds amps today that are much better than amps 20 plus years old. SS amps today have far less grain and can sound every bit as good as a great modern tube amp. Parts quality has greatly improved, so if an amp is built with these SOTA parts, it will indeed sound much better.

We have learned and applied a great deal with damping and shielding inside an amp. Power supplies are better and on and on.

Just takes some effort to find one that meets your sonic preferences.
Mitch2, I know of another Audiogon member who swore by a highly modified McCormack amplifier.....until he heard a McIntosh tube amp from the 50's. He wound up having the McIntosh re-conditioned, and sold the McCormack. He was stunned to find out how good a 55+ year old tube amp could sound.

I'm just saying that many folks will swear that newer technology is always better, we are constantly improving.....then how come my old tube amp and vinyl beat digital with newer amp?

Is newer technology different? Absolutely! Better? Maybe to some.
Since 1994, I would point to;

1. an increase in differentially balanced designs, where two identical halves are bridged for significantly higher power and lower noise in balanced mode,
2. the use of input transformers for isolation, balanced conversion and other reasons,
3. better parts, power supplies and isolation as has been pointed out above, and
4. most recently the maturation of really good sounding Class D amps like the Ncore NC1200 based amps which, in my system, sounded great.

Regarding improvements since 1994, I believe my "new" amp was manufactured in 1996 and introduced in Jan '97. It is a McCormack DNA-2 LAE that I commissioned Steve to rebuild using everything he has learned about upgrading those amps from circuit changes to the best available parts. The result IMO sounds outstanding and rivals or betters any amp I have owned or heard in my system.
To head off confusion as to why John's reply came before my post, before he posted I made a small change and the formatting on the preview ended up weird so I copied the text, deleted the post and reposted with the revision, but by then John's reply post was already up.

I am not surprised that resurrecting a classic tube amp would have a satisfactory result. Better parts and circuit/wiring layout to reduce noise are two improvements of newer amps over older amps but if the design is strong a rebuild with newer parts can provide significant improvements. In my case, I specifically did not want tubes. If the McCormack amp had not turned out as good as it did, I probably would have been looking at a pair of Ncores.
I don't call it an improvement one day maybe when technology has let them get to use switching frequencies 10 x higher than now, but class D is the only real new technology I can recall.

Everything tube or transistor although bigger, heavier, and better built these days, can date it's base circuitry back to the 1940's 60's and 70's things like Williamson tube designs, and same goes for SS.

Cheers George
Thanks for the explanation Mitch! You had me scratching my head for a minute there. LOL!!
I am in the camp that the transformers on the tube amps from the 50's & 60's improve their sweetness with age and the new gear especially SS & class D proably won't have that advantage.
I don't call it an improvement one day maybe when technology has let them get to use switching frequencies 10 x higher than now, but class D is the only real new technology I can recall.

Everything tube or transistor although bigger, heavier, and better built these days, can date it's base circuitry back to the 1940's 60's and 70's things like Williamson tube designs, and same goes for SS.

Cheers George

Even class D technology dates back to the late 50s. Although as far as real sonic improvements, those may be dated after 94.
Of course the 1994 amps sound better - they've had 20 years of break-in. Just wait until they've been in service for 50 years. They will be so broken in they will be better than a live performance.
Sorry to disagree with George, but there are new topologies.
The devil is always in the details.
I tricked out a pair of Dynaco MK 3s with the best parts, silver point to point wiring, big capacitance in the power supply,… It sounded good, but still dated.
Today we are spoiled with this high end gear. It has less distortion of all types.
I am not saying that older gear sounds bad but design goals have changed over the years.
As for vinyl vs. digital, that is a different argument altogether.