Today I have mainly been listening to a Quad 303. Recapped etc by Dada. 5600uF output caps used.
Somewhat better than I recall of standard but not recapped (and fitted with much smaller original output caps) units.
Overall I prefer it to the last Quad amp I had in, a 520, by a fair margin.
A nice lack of any "nasty" "transistory", "brittleness", "chrome" etc to the mid and treble. Imaging and soundstaging very good.
Compared to my usual Arkless Electronics 16WPC class A monoblocks (much more expensive amp if you could buy one) though it is rather lacking in dynamics, "balls", slam, "range of timbral palette", somewhat lacking in deep bass extension and a bit loose down there. The top end is a bit "soft", "rounded" by Nth degrees but no huge difference.
Subjectively it sounds considerably less "powerful" even though it's actually 45WPC compared to the 16WPC of my own amp and "smaller" (hard to put into words but smaller will have to do). Dynamics don't "startle" as they do with the Arkless Electronics monoblocks. I can see why the aphorism of "better on classical than rock" has been used at times in relation to the 303... not that it can't do rock you understand... it's just maybe not it's forte.
For the price you can get a S/H 303 and ease of servicing though... Recommended