My Sansui Au 7700 so good it was and so good it is right now will not compete in sound quality ( his versatility is unmatched though) with the Berning ZOTL technology which is  a bargain it seems in Audio offerings...

My exemple is valuable for other brand name for sure...

But my Sansui is enough for me twenty times less costly .... 😁😊

It was a legendary product and it is enough to reach heaven  especially in a controlled  acoustic ...

There is always progress.

But to answer your question:

Can a Amp be "timeless" and compete with todays amps?

The correct answer is ’no’. The single thing that has held back amplifier improvement is something called Gain Bandwidth Product (GBP). Over the years you may have noticed that feedback in amplifiers has gotten a bad rap. This is because limitations in GBP have prevented enough feedback from actually being applied. The result has been that the application of feedback has resulted in added distortion on account of the feedback itself, and increasing distortion with frequency above a certain point.

This has caused feedback to be conflated (and rightfully so) with harshness and brightness.

What happens if there is insufficient GBP is that the feedback starts to fall off at higher frequencies and so with less feedback comes greater distortion. If you graph distortion vs frequency you can see this in almost any amplifier made in the last 60 years employing feedback. Since the ear converts distortion into tonality and since the ear is keenly sensitive to the higher ordered harmonics generated by feedback itself, the result is harshness and brightness over the last 60 years.

That is why there are many zero feedback amplifier designs. Zero feedback is about the only traditional way of getting around this problem.

If you can manage about 35 dB of feedback in the amplifier design and there is sufficient GBP, the result is that the feedback can ’clean up’ its own mess, resulting in less higher ordered harmonics. Since the feedback is consistent at all frequencies, the distortion and the distortion signature (the spectra of harmonics) does not change as frequency is increased.

Its a simple fact that no tube amp is capable of this! You need a lot of gain and a lot of bandwidth; the former is simply not available in tube designs without associated phase shift, which would cause the amp to oscillate at some higher frequency.

There are now designs that satisfy these goals, designs that were not possible 20 or 30 years ago because the amplifying devices didn’t exist.

What this means is its possible to build a solid state amp that is every bit as smooth in the mids and highs as the best tube amps and leave nothing on the table in terms of detail, sound stage and the like, in such a way that vintage amps simply cannot compete (not that they sound bad, just they don’t sound as good). This is one of those things that is easy to hear and easy to measure.

IMO, I totally agree with atmosphere...well written and it just magnifies how stupid that statement "amp is an amp" is...

I agree too because he know what he is talking about ...

We cannot reduce technology progress to embellishment only for sure...

I would sincerely suggest to the OP to listen to an example of a modern high negative feedback solid state amplifier as described above and compare its sound quality to the Renaissance 70/70 and be your own judge. I’m not convinced that the "modern " high feedback would be  superior sounding. Hard to know which you will find musically preferable without an actual listening experience.

Charles