Lifespan of a quality solid state amplifier?

I have an over thirty year old APT Labs amplifier that is still running a pair of old 1979 B&W 801's! Yes, it's a 100-watt amp into 8-ohms and runs near clipping all the time. It sounds fine.

Electrolytics are no better than +/- 20% tolerance so that wear is less sensitive than you might think to sound. Caps in the more sensitive audio path that are non electrolytic give you a better circuit life if anything. There is no "proof" that exotic caps sound better over just last longer (at a price). Large electrolytics in the power path are cheap to service, too.

Most smaller electrolytic caps, if mounted right to lower lead inductance, often have the lead end (where they leak) SHORT and right to the PC board. You can't see the caps leaking when they do go till it's too late. Large power stage electrolytics are faced "up" with the terminals using screws. Inductance isn't as important in the DC path. You can watch these for signs of deterioration.

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Rower

What you say is just plain wrong.

Unless it is bulging or leaking fluid it is impossible to visually inspect a cap and determine if it has deteriorated. The capacitance drops and ESR goes up and they leak current and you have no way of knowing if or how much just by looking at it. You can delude yourself if you wish but all electrolytics slowly deteriorate in ways you cannot see.

All electrolytics have a limited lifetime. Take a minute to google the topic and you will get hundreds if not thousands of hits discussing this phenomenon.

It is impossible that your 30 year old caps function as well as new ones. To deny this is to deny that which has been studied extensively and is well documented. Your amp may sound "fine" whatever that means but that does not mean it wouldn't sound better with fresh caps.

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No, you just push statements you're trying to justify making using my post. Do it on your own, please. I did NOT say counter to what want to say, I did say the effecets are less severe than MEASUREMENTS would lead you to believe! READ it again. If the caps aren't looking bad and it sounds good, keep on trucking.

If you keep electrolytics out of the audio path, a power supply has less effect on the overal "sound" than touted if the supply was decent to begin with. Older electrolytics aren't the same as new, but the FUD is overblown. True, gross failure not withstanding. ESR change in a electrolytic capacitor in a good circuit doesn't doom an amplifier to a severly limited lifespan.

Large electrolytic capacitors are GROSSLY variable right out of the box. But, on the power supply side it makes little difference to the sound. People LOVE to talk ESR, but know little of how it effects a circuit..it just "sounds" good to pretend any change is audible. We also take RF circuit design and pretend it works at audio (basically DC realtive to RF).

http://sound.westhost.com/articles/capacitors.htm

YOU need to read-up on facts about types of caps and degradation and why, not to mention their sound, or lack thereof. There is more snake oil in audio than in snakes.

When I say the amplifer sound fine, I mean it. As good as a new Mark Levinson? No, of course not. But to simply say it is older so it can't sound fine is nonesense. I listen to it (fact), and you simply read about it (no fact at all!). I also have New KISMET ODYSSEY amps running C4's, so I do happen to have a new reference.

So I LISTEN to this amplifer which goes a LONG way to saying the older caps are plenty servicable, still. "Comments" of differences in sound are pretty baseless since you haven't even listened to the amplifier. True, I don't take out the caps and measure them all but the point of the post is OLDER amps can still sound fine. Mine does. Are the caps the "same"? Of course not.

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sorry................

your rant is just about impossible to follow

Sober up and then formulate a response.

Your position that power supply caps don't matter could not be further from the truth. They are the heart and soul of the amp. I build my amps and can assure you from experience that caps do affect the sound in a major way.

Taking one incidence (your old amps still work) to justify your stance makes as much sense as saying smoking is good for you because you know someone who is 95 and smokes a pack a day. There is a huge amount of data that says otherwise.

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In the manual for a Pass Labs amp, Pass says in the most common sense no bullcrap manner something to the effect that it will take a LONG time for caps to fry, and the caps let you know when they're dying so you'll have plenty of time to get 'em fixed. I've inspected my circa 1997 Forte' amp and it looks fine, sounds GREAT, and sure, I'll send it to Soderburg eventually...eventually...