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What is the life expectancy of electrical components?


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From shortest to longest how long do the parts last ie capacitors, resistors, diodes etc.. solder joints? What I'm really wondering is how long, for example, does a pre amp or power amp last before various parts need to be replaced?

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From a shelf life perspective, some capacitors decay with time, but some can be reformed.  resistors, transistors and diodes don't have a significant shelf life limit.

Heat is a significant factor, as well as build tolerance.  Build tolerance meaning

- if the unit calls for 80 volt capacitors, and 160 volt capacitors were used instead of 100 volt capacitors
- 1  amp diodes were needed, but 3 amp diodes were used
- 1/4 watt resistors required, but 1/2 watt resistors used
-- transistors required to deliver 7 amp current, but 15 amp capable transistors used
- fans and large heat sinks

I've owned amps that were original and never modifed that were 30 years old and worked fine on one hand....on the other...had some that were less than 10 years old that bit the dust.

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Thanks Fritz. I can always count on you. I just spent about $600 on my 21 year old Audio Research tube SP 11 and its power supply. Plus $180 for six of there exclusive Russian made to spec tubes. I paid $5000 for it back in 1986 and the blue book value is currently $1850. My old tubes were shot also. Anyone interested in new JAN SYL 6dj8 tubes. ARC said the JAN SYL tubes would be ok but their Russian tubes would be better. I have 10 6dj8's ALL THE SAME LOT # that I'll sell for $70 [that's $7 each] plus actual shipping cost.These tubes are selling from $10 to $20 on the internet and you won't find 10 the same lot #.

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If you are talking tubes then you have my sympathy because you will always have to be on the alert to determine if any of the tubes need replacing.

I was sooo happy when in the early, early 60s they began offering solid state amps amd pre-amps. I was happy because of the reliability factor of solid state equipment.

speakerfritz gave you a great and quite accurate answer. Thanks Speak.

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About mid 70's leads became copperweld on many parts (carbon comp resistors used in older SS and tube gear have pure copper leads).

On copperweld, the copper comes off the steel and the part fails after 20+ years.

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I have a Dyna PAS-3 tube preamp that is 39 years old, and has alternated between hard/constant duty and months/years of disuse. It works fine. Only one tube change, and that was just a precaution on my part when I couldn't afford to risk a tube going bad.

I loaned it to a university for some 21 years -- it came back in as good condition as ever. Now, I use it whenever my current preamp needs to go to the shop.

It does have a little more hiss through Klipschorns than my SS gear, though.

The best sounding SS amp I ever had, a Luxman, "only" lasted about 20 years, and was pronounced beyond repair (I always doubted this).

Then there was a McIntosh C28 preamp. McIntosh has a great reputation for reliability. The damn right channel on phono went out repeatedly.

Make no bets.
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The authoritative manual on electronic component reliability is the Rome Air book, not the full title but should be enough for Google. I will try to find the full title and ordering info. This is Rome as in Rome NY. It is a compendium of DoD reliability studies and is considered the reference for reliability figures used in system analysis.

However, a note of caution: these are components considered in isolation and not whole circuits. As I'm sure someone else has pointed out, caps usually go before tubes, and any component that sees a lot of voltage and current tends to die before components that see little of each. I've seen 60 year old radios with original tubes that are fine, it's the caps, pots and sometimes transformers that are shot.

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I can give you an on hands description of military electronics ---1950,1970 era. Vacuum tubes short, emissive, and noise failure, cooling fan bearings, water leaks onto electronic chassis shorting everything out, klystron tube failure, conventional relay contact failure, potentiometer intermittant performance, ground connection to chassis corrosion, coolant pump failure, coolant pump belt failure, fan belt failure, coolant pipe internal corrosion, zener & conventional diode failure, high power RF arcing (gold, copper and teflon failure), chrome/berilium contact failure, power supply drifting causing excessive alignments, built in vacuum tube inductance & capacitance raising hell with sensitive circuits varying from batch to batch particularly local crystal controlled UHF oscillators and intermodulation distortion in FM phase modulators, Ended up using special Western Electric tubes in these circuits. Also defective RG-58, RG-59, RG-62, RG-8, Type "N" , RG-11 connectors and cables which we installed new connectors to our specs with soldered connections. (very time consuming) (sweep from 3 megs to 900 megs and not pull apart). If the shield on these connectors is a bit logrithimicly placed on the metal instead of linear or a couple strands are missing you will get dips in the sweep spectrum. Those connections have to be perfect.

And don't use a metal flashlight when working on your equipment.

PS: We went thru bushels of tubes to maintain spec. 24/7. After the new Solid State stuff came in to replace the tubes we were in Nirvana land. Sat around and told stories. Of course this is unsubstantiated inuendo.


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