I have 2 Naim amps. The Green Naim logo takes much longer to fade away after switching off on one compared to the other.
It made me wonder if there is any link between fade time and capacitor “health”. In other words is a shorter fade time indicative of capacitors that are wearing out?
Different boxes with different quantities and capacity of charged components might drain unequally when switched off. 
My XS3 takes an absolute age to fade down
The CS5si has a much shorter fade time
Yes, that makes sense but do you think there’s anything in this for the same amp? You would imagine they all leave the factory with a similar fade time (give or take), but those that are left on 24/7 or that get the heaviest use might fade more quickly 10 years later for example. I wonder if it is a potentially useful metric for assessing used kit when purchasing. Obviously we won’t know the factory fade time but we might be able to come up with ranges ourselves.
Unlike @ninanina my xs3 fades quicker than my 5i which is interesting
It’s a meaningless comparison unless it’s the same model with the same upgrade power supplies (or not).
Yes I agree. All the other variables need to be the same, but assuming they are, would it change with time / lifespan of the capacities etc etc?
If we knew the mean (and standard deviation) fade time of a stock xs3 with no external power supply would it change predictably with use?
What problem are you actually trying to solve?
A totally shot cap will not hold charge (you see this on old appliance where you power them on and the LED flashes on for a split second and then goes dim) but an underperforming one that functions will almost certainly read normally when tested with an LCR meter. Fade time of the logo is probably a terrible measure of how good the caps are. For a start, it’s the rectifier caps, not the output caps.
I think the best you can say is that the logo fade time on Naim is long and varies from product to product.
I’m not trying to solve any problem. It just struck me as an interesting thought experiment.
From all of the kit I’ve owned in the past my n-Sub has the longest logo fade out time by a significant margin. Next in line was my NAIT 5Si.
However both my HiCap & XPS DRs’ are very quick to fade out, not quite instantly, but not far off. SN3 a bit longer than both those two.
I recently had my 552 serviced and recapped.
Logo fade time was 437ms before recapping and is now 501ms.
.sjb
If you go for a more expensive mains cable I’d think you could easily duck under that important 500ms mark?
My 252’s logo was going for well over 10 minutes. Only closer inspection I noticed the power button was stuck on the SC. 
Very interesting. That does suggest it may be indicative. Although I suppose parts may have changed.
I’m amazed you had that data. What made you measure pre and post?
I don’t switch off. 
do the white logos fade slower or faster than the green logos?