What does "aging" and use do to an amp?

[kexodusc]

Is it possible to wear an amplifier out? Does it's performance diminish over time? What is the life expectancy of amplifiers and pre-amps exactly?

I'm just curious, there's tons of "vintage" Rotel, Sugden, H/K, Adcom, NAD, etc. amps, pre-amps, integrateds etc in my area at pawn shops and the likes. I saw this yesterday when I found and bought an old, beat up NAD 3140 to steal the power switch and use it for spare parts.

I'm thinking it be kind a fun to try to learn me how to fix these babies up, give them a good cleaning, etc, then find decent homes for them. Heck, lots of them still seem to work and just need the odd switch or fuse or whatever.
Just because they're old doesn't mean they're not good, right?

And has anybody else noticed that old audio equipment is usually built like a tank? When did we stop using steel and start using plastics exactly?

[Resident Loser]

...does just that...

"I'm just curious, there's tons of "vintage" Rotel, Sugden, H/K, Adcom, NAD, etc. amps, pre-amps, integrateds etc in my area at pawn shops and the likes. I saw this yesterday when I found and bought an old, beat up NAD 3140 to steal the power switch and use it for spare parts.

"...I'm thinking it be kind a fun to try to learn me how to fix these babies up, give them a good cleaning, etc, then find decent homes for them. Heck, lots of them still seem to work and just need the odd switch or fuse or whatever...."

"...Is it possible to wear an amplifier out? Does it's performance diminish over time? What is the life expectancy of amplifiers and pre-amps exactly?..."

Heat is the enemy and everything can wear out or go belly-up...I have a tuner and integrated amp that are 30 yrs.old...not too much worse for the wear. Tape decks and such can be problematic...

"...Just because they're old doesn't mean they're not good, right?..."

I agree and prefer the older stuff..

"...And has anybody else noticed that old audio equipment is usually built like a tank?..."

Most things used to be built that way...it's a sad social comment...now things are built to be thrown away and added to the landfills.

"...When did we stop using steel and start using plastics exactly?..."

My simplistic response is HOME THEATER IS TO BLAME...I know it goes beyond that, but I hate what it's done to hi-fi...almost as much as I hate what the proliferation of SUVs has done to 4WD vehicles!!!

jimHJJ(...don't get me started...)

[F1]

Yes amplifiers can wear out. Capacitors can leak, switches can break, potensiometers can get dirty and worn out. But if you are handy in replacing those components the second hand stuff can be a very good deal. I don't think the design from the same brand changed dramatically over time so the new stuff does not necessarily sound better than the one it replaces. Btw, my vintage MF Synthesis has plastic faceplate while current MF amps have thick aluminum faceplate. Sound-wise? Same to me.... (maybe it's just me..)

[kexodusc]

Yeah, that was quite a generalization on my part. These days, most worthwhile gear has quality binding posts, and sturdy backs that can accept fat cables. I find older equipment mostly has the spring clip type terminals or flimsier backs, could be from use.

I do love the simplicity of analog controls though.

Gonna have to try to get this ol' NAD 3140 up and running now. Wonder if NAD will sell me a switch???

[RGA]

I worked at Mcdonalds as my first job and we went through at least 2 receivers a year for the 3 years I was there. Built like crap...Sony Yamaha JVC didn't matter. And the cd players - why they even bothered I will never know.

Older gear from some of the brands you list are well worth a try with modest problems. my Sugden for example has a history of problems with the power on light. When you push the button the light turns on - so wow that light burns out fairly often. You don't need it anyway. Yes this is the problem with Sugden A48b models over the last 30 years. The selector knob needs a tune up and can fail - 15GBP. There are no capacitors in the signal path and theconnectors are top flight. An area where my Arcam Delta 290 had issues. But these are all cheap fixes.

When you can buy such amplifiers for 30% of what they went for new - it's all quite smart.

For power amplifiers I would NEVER buy new. Preamps and integrateds perhaps if I really wanted a specific one that was hard to or impossible to get used.

Tuners - especially digital tuners I would never buy new - no to few moving parts =safe buy.

Used cd player or tape decks no way. External DAC = Safe buy.

Speakers - pretty safe buy as well.

[okiemax]

...does just that...

"I'm just curious, there's tons of "vintage" Rotel, Sugden, H/K, Adcom, NAD, etc. amps, pre-amps, integrateds etc in my area at pawn shops and the likes. I saw this yesterday when I found and bought an old, beat up NAD 3140 to steal the power switch and use it for spare parts.

"...I'm thinking it be kind a fun to try to learn me how to fix these babies up, give them a good cleaning, etc, then find decent homes for them. Heck, lots of them still seem to work and just need the odd switch or fuse or whatever...."

"...Is it possible to wear an amplifier out? Does it's performance diminish over time? What is the life expectancy of amplifiers and pre-amps exactly?..."

Heat is the enemy and everything can wear out or go belly-up...I have a tuner and integrated amp that are 30 yrs.old...not too much worse for the wear. Tape decks and such can be problematic...

"...Just because they're old doesn't mean they're not good, right?..."

I agree and prefer the older stuff..

"...And has anybody else noticed that old audio equipment is usually built like a tank?..."

Most things used to be built that way...it's a sad social comment...now things are built to be thrown away and added to the landfills.

"...When did we stop using steel and start using plastics exactly?..."

My simplistic response is HOME THEATER IS TO BLAME...I know it goes beyond that, but I hate what it's done to hi-fi...almost as much as I hate what the proliferation of SUVs has done to 4WD vehicles!!!

jimHJJ(...don't get me started...)

I love the stuff from the 1970's. Build quality is superb. The Kenwood and HK receivers I have from that period have never needed repairs. If I had the space, collecting would be fun. If you haven't done so already, check out Vintage Asylum, where you will find many guys who are enthusiastic about old hifi gear.

Two external speakers are good enough for my 24" Samsung home theatre -- at least for the time being. I haven't been very impressed by five-speaker demos in showrooms. The sound effects seem gimicky, and the volume makes me want to put my hands over my ears. I wonder whether I will like multi-channel SACD and DVD-Audio.

[filecat13]

Soundcraftsmen is a brand that holds up well. A couple of years a go I purposely sought out and bought four PCR800 MOSFET Stereo Amps (215 W/CH @ 8 Ohms). These were from ca. 1984, so they're now about 20 years old. They are very clean and powerful.

I couldn't get anything today for the $125 ea. (shipped) price, especially something that's stable down to 0 Ohms under load.

They drive everyhting in my HT except for the self-powered subs.

[robin_v]

If you feel that your amplifier is "wearing out" kexodusc, you might want to buy a Densen DeMagic CD and run it and see if there's any improvement.

I play it about once a month to keep my system in trim. (It's only 2:59 long)

[noddin0ff]

"And has anybody else noticed that old audio equipment is usually built like a tank? When did we stop using steel and start using plastics exactly?"

Sure...but you gotta admit that tanks are built much better these days...

[woodman]

If you feel that your amplifier is "wearing out" kexodusc, you might want to buy a Densen DeMagic CD and run it and see if there's any improvement.

I play it about once a month to keep my system in trim. (It's only 2:59 long)

Then again, you might not! Another absolutely worthless product - another classic example of "snake-oil" marketed by a company that's either totally clueless about electronics, or else they're completely unscrupulous.

They claim that all electronic parts (resistors, capacitors, etc.) contain tiny magnets which over time all line up in a certain (not specified) orientation which has a degrading effect on audio signals passing through them! Sheeeeesh! What a crock-o-crap! Not a shred of truth to any of it. The fact that there are (supposedly) thousands of happy, and satisfied users of the product only goes to show just how gullible the poor audiophools really are!

[kexodusc]

If you feel that your amplifier is "wearing out" kexodusc, you might want to buy a Densen DeMagic CD and run it and see if there's any improvement.

I play it about once a month to keep my system in trim. (It's only 2:59 long)

Uhh, no thanks, I bought exotic cables that act as a magnetic field to counter-effect the magnetic orientation, so I know this isn't a problem for me..

Actually, my amp isn't "wearing out", I'm quite amazed how good the ol' NAD 3140's sound 20 years later. I'm waiting for something to happen or something to deteriorate.
Surely, sooner or later this thing is going to die on me right?

[markw]

Surely, sooner or later this thing is going to die on me right?

Well, I've got a Marantz 2270 I picked up over 30 years ago that's still working fine. I had the FM aligned twice in that time but all else, aside from occasionally spraying the controls and contacts, has never needed servicing. ...and, if I wasn't so honkin' picky about my FM, I probably would have been perfectly satisfied without those two alignments.

...not to mention a Marantz 7C/8B pair that have only needed tubes since the 60's.

[kexodusc]

Well, I've got a Marantz 2270 I picked up over 30 years ago that's still working fine. I had the FM aligned twice in that time but all else, aside from occasionally spraying the controls and contacts, has never needed servicing. ...and, if I wasn't so honkin' picky about my FM, I probably would have been perfectly satisfied without those two alignments.

...not to mention a Marantz 7C/8B pair that have only needed tubes since the 60's.

So what you're saying is my NADs are invincible....I have invincible NADs!
Invincible!!!

[skeptic]

The three main enemies of audio amplifiers insofar as aging is concerned are heat, moisture, and oxygen. Depending on the nature of the equipment, the quality of the parts, and their environment, the process can be so slow as to be glacial or relatively rapid.

Moisture accelerates oxidation. All exposed moving mechanical parts such as switches and potentiometers are vulnerable. Usually occasional cleaning is all that is needed to restore their original performance but sometimes only replacement is satisfactory. Some capacitor dielectrics can break down over time but this is much more typical of those used 30 or 40 years ago than today. Inductors rarely fail. Resistors in solid state amplifiers rarely break down but in tube amplifiers, heat can cause long term degradation especially of carbon types. Heat will rarely break down the insulation on transformer windings. Often cascading failures are the cause of transformer failure, meaning a failure in one circuit causes a failure in another.

The biggest culprit in "aging" is heat, especially heat generated by vacuum tubes. They not only damage other components, they slowly damage themselves;

As vacuum tubes age, the ability of the cathode to emit electrons is reduced. This can result in a change in gain and other characteristics. The way engineers have mitigated this problem is the use of negative feedback which not only reduces distortion but stabalizes operation making it less dependant on the condition of the tubes.

There is no known aging process in transistors. Any change which damages the crystaline structure is almost always catastrophic and always irreversible.

BTW Woodman is correct about there being no value to some sort of demagnetizing circuit or signal in audio equipment. Thre are only three materials which exhibit strong magnetism, iron, cobalt, and nickel. None of these exist in most electronic components except in the cores of transformers and inductors. The steel in transfomer laminations is made from a special magnetically soft material called permalloy or supermalloy. They are intended to be constantly magnetized and demagnetized and they do so 120 times a second. They cannot carry any residual magnetism because of their inherent metalurgical structure. Those in chokes such as tuning slugs in rf stages of older tuners simply increase inductance and are used to tune the circuit by their phyical location of the ferrite core within the coil. You cannot affect them with any kind of signal but if you could, all you would accomplish would be to throw the tuner out of alignment.

[FLZapped]

Those in chokes such as tuning slugs in rf stages of older tuners simply increase inductance and are used to tune the circuit by their phyical location of the ferrite core within the coil.

Well, unless you use aluminum, which reduces the inductance as you move it into the coil.....


In general, electronics tend to follow a bathtub curve. Some infant mortality failures up front, then a long period of reliability, followed by increasing end of life failures. So if well designed, the bottom of the bathtub could be 20 or even 30 years in length.

[skeptic]

Some electronics might last a lot longer than that. I'll bet there are early well made solid state units like Crown DC 300 which will test out today like the day they were made. I don't accept that all electronics have a performance deterioration curve measured in decades. Because they are reletively recent items it's much too early to know but some may be measured in centuries. Many years ago, engineers familiar with the Atlantic Cable told me that before a vacuum tube qualified for use in the cable, it had to prove itself by giving reliable service continually for 25 years.

[E-Stat]

The three main enemies of audio amplifiers insofar as aging is concerned are heat, moisture, and oxygen.

Do tell me if I'm wrong, but I've also heard that disuse can be deleterious to electronic circuits. I regularly use a 23 year old Threshold power amp that still works fine.

rw

[topspeed]

I have invincible NADs!

Yer a lucky man KC!

[woodman]

Do tell me if I'm wrong, but I've also heard that disuse can be deleterious to electronic circuits. I regularly use a 23 year old Threshold power amp that still works fine.

rw

You are quite correct, sir! In my many, many years of servicing experience, I reached the inescapable conclusion that any electronic product that sat idle in a closet or in a garage or in an attic or in a storage facility for an extended period of time, was going to be about as reliable as George W. Bush!

[markw]

Yer a lucky man KC!

Like they say, you'll be all right as long as you keep the juice flowing through 'em.

(Gawd, I don't believe I just said that)

[skeptic]

I think it would depend on the storage conditions and the equipment. Military grade electronics are required to perform reliably under enormous variations of temperature and humidity. The designs usually also make them inherently more immune to failure or performance drift than commercial or consumer grade electronics. So does telephone company equipment designed for use in Central Offices. Degradation of electronic equipment through disuse not associated with storage conditions other than the oxidation of switches and other contacts probably result mostly from deterioration of capacitors and buildup of static charge on transistors. On the other hand, mainframe computers have a dismal record and the managers of such facilities usually panic if the temperature rises in their computer rooms just a few degrees. (An AT&T tech wanted to prove to me that a 5E telephone switch would operate at 125 degrees in my facility by turning off the air conditioning system. I told him thanks but no thanks.---my luck the fire sprinklers would have gone off.)