Electrolytic capacitor life is nuanced, and they do last a very long time. Naim uses long-life capacitors, and their duty is ‘de-rated’, i.e., they do not reach their maximum ripple current or operating temperatures, and are generally not heavily used 24/7 (i.e. the unit is on, but muted for 12 hours a day). They will last decades.
It is best to enjoy our systems to their full potential and ensure they are well ventilated.
Electrolytic capacitor life.
If they are left ‘on a shelf’ for many years and never used, there is no voltage across the capacitor to maintain the dielectric. They will also degrade. The oxide or insulation between the capacitor plates will thin, and the voltage leaks from one plate to the other, i.e., it goes out of spec. New old stock (NOS) should be gently charged until the oxide layer regrows and the leakage drops.
If lightly used, like in an amplifier, they will have a formed dielectric layer and not get overly hot.
Under heavy industrial use (not Hi-Fi), 24/7, in a warm environment, the electrolyte may dry out, and its internal resistance or ability to provide transient current may be reduced.
A hypothetical maximum life may come from powering them up for 30 mins or so for the oxide to grow (measure leakage current until it drops), then disconnect for a few months and repeat. Not very useful, though. Leaving power on 24/7 may have a shorter life than occasional powering. I have not tested this.
The quality of modern capacitors is constantly improving. They are exceptionally good now.
I’d really like to clear up this gray area on Naim’s current official position. People have been paying large amounts of money to get their products serviced every 10-15 years per Naim’s recommendation and now you make the statement that Naim uses capacitors far below their limits and that they last decades. There has also been talk on the forum that products without internal power supplies (preamps, sources) don’t need to be serviced every 10-15 years all while Naim has never made an official statement excluding those products from the normal service timeline. Do you feel this is correct?
Can you clarify for the record why you state the caps last decades, but at the same time recommend a service every 10-15 years?
Do you believe that turning the products off when not in use pushes back the need for service? I’ve seen you state that it does, but I’m just asking directly for the record.
After 10-15 years, depending upon the product and usage, if the caps are replaced (and other service items calibrated, changed, etc.), it restores the sound to like new. If not replaced, the equipment will last for many more years and still sound great.
They do not stop working, unlike capacitors that are not de-rated. Such as in extreme value electronics like TV screens.
Theoretically, turning it off will increase the life of the large capacitors. This is such a small amount, as the temperature effects are small. Certainly, in terms of value for money between purchase and service, use the equipment as much as you can and leave it on.
It is good practice to make sure all electronics are in a well-ventilated area for the best life. Engineers use the Arrhenius‑governed chemical and physical degradation processes. Please do not get concerned and enjoy the music.
Having recapped more things than I can count, I think it is fair to say that the period of time it takes for a cap to fail is usually (not always) pretty long, several decades. But the period of time over which their behaviour changes (such as their ESR) is shorter. For the majority of home electronics, functional until failure is expected.
You start to see a change in performance after a few years. Even new caps have a pre-production shelf life (clearly documented in their spec sheets) of 24 months usually. They are perfectly fine after than but as there is no knowledge of the product manufacturer’s intended warranty (could be 90 days, could be 20 years) a cap should generally find it’s way into a finished product within 2 years.
There are exceptions. When you replace hundreds a year as I do you see ones that failed in their first few years. And you see some that are 40 years old that measure good.
With audio, it’s less about failure and more about that sweet spot of optimum performance. You can drift out of that and be, from a functional perspective, perfectly fine.
I seem to remember when the NC was launched there was a discussion there about caps and some design changes made over previous generations and if Steve will permit me to make a vague attribution to him (I can’t find the original comment) the NC range should go longer before recapping - as has every range in comparison to the range it replaced. But it’s still too new to know that yet.
Bear in mind a “recap” is part of a larger service that includes checking things like connections, wiring, etc. It’s normal to see on a service worksheet from Naim that caps were replaced as well as other components on a per service basis. Someone might get a unit back were rusted input sockets were replaced, some resistors, and dodgy looking solder joints redone with new wire. All sorts of things can happen.
Do they have a position? Sounds to me like Steve is just stating the universal reality of capacitor lifetime and performance so that people have a realistic expectation.
Surely Naim are just protecting their reputation. Things wear out or degrade. Naim suggests that you keep tip top performance by having an optimal life cycle for some components. Whether my usage cycle is the same as yours, or my environment is colder, wetter, faces east or west isn’t the point. It’s not a proven scientific experiment in controlled conditions. It’s just an advisory to get the best sound from Naim kit. Take it or leave it.
As a long time Naim user I am comfortable leaving my system on 24/7. I remember a topic a while back calculating costs over a year which seemed pretty minimal, at least to me.
On the subject of servicing I had all mine ‘done’ as I moved into retirement. They will not be sent again unless a fault develops. Tbh, not sure I heard any improvement after servicing except perhaps from my 252 which needed a new pot and a software update some years ago. It does give peace of mind that everything is optimal though.
As an electrolytic capacitor ages, its characteristics slowly change. After 10-15 years, the ESR or ‘effective series resistance’ increases. When ESR increases, the PSU will have a larger, distorted imprint of the audio signal superimposed on the rail voltage. This signal on the rails, albeit very small, is added to the main output signal. This will affect the sound compared to when it was new. After decades, the wet electrolyte in a capacitor can dry up. When this happens, it may short-circuit. At this point, the amplifier will stop working. It is best to avoid this.
Capacitor ageing, contact oxidisation and resistor drift, etc., are not exclusive to Naim. It is the same for all manufacturers of hi-fi, domestic or industrial equipment.
An original Nait from the 1980s will work today. Once it is serviced, it will sound like new. Several other companies also offer servicing, including McIntosh, Audio Research and Accuphase. We are very proud to offer this service, and our service team’s product knowledge is incredible.
Seems to me Naim’s approach to service and longevity are top tier. Send your equipment in every 8-10 years (olive) or every 10-12 years (OC, NC) and it sounds like new. Short of funds? Then keep running it for years more and it will run fine.
I had my olives recapped 5 years ago for the 3rd time and the price was fair and the results were excellent. Now for the preamp moved on to the NC and it is just amazing and in time the company will make them new again for a fair price.
Now that I asked him to elaborate, sure. When he makes statements like capacitors “will last decades” without elaborating by stating they also degrade over time, which can have an effect on SQ, then I felt it deserved clarification which he provided. Now it’s clear for anyone who wants to quote him in the future.
I have no problem with recapping every 10 to 15 years. The effect for the olives was always great.
Will do that for the psu‘s for 552 and 500 soon. They can be done locally I hope/think and do not need to be shipped to the uk.
That will be like +4000 EUR. Happy days. Or half if only doing PSUs. But will you find peace in taking care of half of the system only? Personally I would likely think “but what if”.
Interesting! It could be my illusion - After running in the NAP 350s for more than a week, I feel that the music becomes quieter, more refined, instrument separation, layering, timbre more prominent.
With my Selekt Edition I have reverted to using the Linn silver XLRs into my NC250, and have had Naim Superlumina speaker cables from the NC250 to speakers since January.
Conversely I prefer a different XLR cable (Studio Connections Back Star) from my Atom HE into the NC250, when I want to run the HE as an alternative main source, but always the SuperLumina - which I find better than the Kudos KS1, which I also have here, with a Naim amplifier.
That’s what I did. They sounded great from first switch on and then went through a bit of a strange period where they sounded really tight and constrained, so much so that I checked I hadn’t invoked a strange SO profile on my KDSM. The bass finally returned and once things settled down I enabled auto standby and haven’t felt any need to leave them permanently on. Two years into ownership now.
Enjoy your 350s when you return home. Superb amps, only let down slightly by getting a bit vocal at times due to local mains. It’ll be interesting to see if our Solar install will affect things here.
One of the solar things we did…….had to upgrade our main house fuse from 60 to 100 amps. This was free of charge by the DNO, expected a better SQ, but just the same.
The solar/battery seems to have brought a more consistent sound. A look at either side of the gateway for going off grid during power cuts shows a much more stable voltage and current from our inverter…….may just be where we live?
