How does one "know" if capacitors need changing?

I need to dig out my trusty Audiolab 8000A (purchased 33 years ago for GBP 199.95 !) to act as a stand in amplifier whilst my SN3 goes back to Naim for a fix. Whilst I am not expecting it to sound anywhere near as good as the SN3, what would I be looking out for WRT capacitors etc?

TIA

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Unless they are visually bulging, leaking, or it sounds funny, the only way you can “know” is to charge them and test them with a multimeter or better yet, an oscillascope, against their rated spec.

At 33 years, any cap will need replacing, even film ones.

After 33 years it will need service to sound its best imo.

I retired my 8000A from 1995 a couple of years ago with an XS3 and wow, did it make a difference!

I knew the 8000A needed a service as it had never been serviced before. I still have it as a spare in case of emergency.

I imagine a service would get it sounding great again as it was when new but I’m also certain the XS3 is much better SQ all round.

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Electrolytic Capacitors have a limited like, starting from when they are manufactured. Naim say:

How often should I service my Naim product? This is a question often asked, and the Service Department recommendations are as follows: for the Chrome Bumper (circa 1975 - 1989) and Olive (circa 1989 - 2000) range products, we recommend every 8 - 10 years and for the newer Black products (2000 - present), every 12 - 15 years.

Crackling sound from the speakers is a sign of worn out caps.

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There is no and hard and fast rule, regarding how long capacitors last, and it doubtless depends on the capacitor’s specific design anx operating conditions. I sent a Musical Fidelity P270 for service at about 25 years old, thinking it was probably high time it was re-capped, especially as it is a very hot-running amp due to strong bias into class A. Whilst they did indeed replace some caps, that, interestingly, did not include the reservoir caps, which apparently were found to be still satisfactory and within spec. I couldn’t tell if there was any difference in sound when it came back, so if so it was small.

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Was that sent back to MF?

Yes

My guess is when they’re incapacitated. I’ll get mi coat.

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MF, and by that i mean their owner/MD had a different views on components including caps. His view being that they were all the same, so he bought the cheapest. Their service manager knew different, and this was one ( of the many) reasons they left. Starting their own business servicing and upgrading MF kit.
Which in turn caused MF to provide aftermarket upgrades ( that werent!)

Interesting! At least it seems that the choice of reservoir caps was good in terms of longter stability/reliability. (The amp sounded good, too)

Well, there are plenty of electronic audio components from the 60s and 70s that are still going strong. I guess their owners don’t know anything about “recapping” and the perils of not doing so.
Or do they … ???

They might have used condensers instead?

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When Elec. Caps. start leaking gunge over the circuit board might be a clue………

I had my pre-amp hi-caps and monoblocs serviced recently and the improvement in sound staggered me. It was night and day. The only advice I would give is to think of it as an upgrade, your system will become more transparent and dynamic.

I think , we can hear when you turn on your Naim and you hear when there’s no sound from your source and you hear some distortion like " tik…tok…tik…" with noticeable when your surroundings is silent

How much of the improvement is due to non like for like replacements with modern “ equivalents”?

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I have finally bitten the bullet and organised for my kit to go back in January. Bought new in 2003 the Supercap and non DR 300 are overdue and the system has been strangely less engaging in recent weeks. Fortunately only three boxes as the 252 has already been done and the other boxes are less than two years old.

At £1200 the cost of piece of mind and the hope of a small improvement will be money well spent and at 62 unlikely to do it again! I am not looking forward to four weeks of quiet though so getting some reading organised…

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