My CD front end is new. Otherwise I have vintage gear (new when bought) because I don't see a reason to switch. Yes, my 24-year old mini-monitors (Ensemble Reference) are modified with internal cabling, crossover and new tweeters. My also 24-year old parallel push-pull triode amps are internally modified as well, and were recently supplemented with BorderPatrol external power supplies, a substantial upgrade.
How does it all compare to more recent stuff?
1. Speakers:
I have listened 2 years ago to two-way floorstanders from a currently 'hot' company in the same price range as my mini-monitors (inflation-adjusted). At first they appeared to have somewhat higher resolution, but upon longer listening it was clear that this was an artifact of emphasis on the lower treble, creating a tonal balance that I did hear live on a few occasions, but rarely. The balance of my speakers is much closer to my average live experience. At high SPL (around 90 dB) the floorstanders completely fell apart in grinding congestion, really embarrassing. At these SPL, and quite a bit above, my speakers play quite cleanly in a much bigger room. Rhythm & timing of the floorstanders was abysmal, while that of my speakers is phenomenal.
I also heard a pair of new mini-monitors, albeit in a lower price range, and my own speakers destroyed them in a quite bloody fashion. They did all the same things, but with far less coloration.
My REL Storm III subwoofers are 15 years old, but have fast and clean sound. They integrate seamlessly with my mini-monitors. After the latest acoustic upgrades, the midbass of my combo can compete in strength and quality with a large floorstander. Overall, I have not yet heard a better bass from any other system.
2. Amps:
As tested at home on my speakers, my amps could easily compete with a Spectral DMC-15/DMA-260 pre-amp/amp combo -- and that was before the substantial upgrade of my amps with external power supplies. Tonal balance was nearly identical. Of course, the Spectral can drive almost any speakers, and my low-powered (15 W pch) triode amps would fall apart on most. Yet on my 90 dB sensitive mini-monitors their performance is excellent. No need to consider anything else.
3. Cables:
Two years ago my now 22-year old Monster Sigma 2000 interconnects and speaker cables could quite well compete with MIT/Spectral cables in my system. On some music (e..g solo violin) high-energy transients were a tad slower and less clean, but that problem was fixed with an upgrade elsewhere in my system -- the external power supplies for my amps. No need to switch at this point either.
The verdict:
1) I don't have vintage gear for nostalgia, but for sound. When I bought my gear, it was new, and in terms of sound quality there is no need to switch to current stuff only because it's newer.
2) Progress in audio is overrated. Yes, there are landmark new designs, like for example the Magico M Pro speakers and the best current SOTA digital, and the best SS amps have become much better, but I am not so sure if everything is considerably better than 20 years ago. Of course, if you would believe all the breathless audio reviews, everything is now much better than the stuff 3 years ago, which in turn was much better than…oh, well.