OK. We were on the way out with the brand by the time of the 500's, but I remember two samples of 506 CD player made several months apart heard fairly close to each other using similar gear and comparisons and one sounded dull and the other thin toned (this kind of thing happened in the subjective-only days of the late 90's). Mid period Linn Karik CD players were the same, the motherboards changed a few times in the mid 90's and results at the time I judged quite audible. The 502 'balanced' preamp was a delight and didn't change and the 501 RCA-only model wasn't so good in reproduction of reverb/acoustic, but it had a revision (not sure if it became a full mk2) and that sorted it out.
The thing is today, with a far more objective bent, it's easy to dismiss these subjective findings as nonsense and imagined and I can't dispute that at all. But I can think of a handful of UK makers back then who did seem to design and somehow 'voice' their products to get good subjective reviews. All this time, there were mid priced CD players by Denon for example, which held to pretty much neutrality (and have stayed the course because of it) and my preamp reference then was the Bryston BP25 (which I still maintain needed some hours after a cold start before fully settling down subjectively - my experience and opinion and I'm damned well sticking to it, so there!
)
As for seriously good vintage amps which may compare well today, it's difficult. Bryston was mentioned earlier and I feel the 70's Crown/Amcron amps should be considered as well. Ken Rockwell has measured a few and 4 ohm loads apart (when protection can kick in), they're not bad at all still for fifty year old designs. I remain delighted with my inherited pile (IC-150's lightly serviced, D-60's and a cheap D-150 which needs the optional front panel to dress it up) and they seem 'honest' enough for my needs as my speakers don't dip below 6 ohms. Here's my actual power amp in all it's flaking paint glory from the ad. DC offsets well within spec and I haven't tinkered.
View attachment 244562 View attachment 244563