Can amps lose their high frequencies over time?

Discussion in 'Audio Hardware' started by everton, Jun 10, 2021.

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  1. Helom

    Helom Forum member

    Location:
    U.S.
    Capacitors can last multiple human lifetimes if operated under normal conditions. Caps don't drift out of spec as often as audiophiles like to believe.

    Take break for a week and remake all the connections before you fire it up again.
     
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  2. everton

    everton Forum Resident Thread Starter

    Location:
    Canada
    Thanks to everyone for your reply.


    I did not do that. I will clean them this weekend.


    Sadly, this may be what has happend to me. I have just taken hearing frequency tests on a few web sites. I know that the results are not accurate and depend on several factors. But the results seem to suggest that my hearing maxed out at about 11 kHz. In fact, one web site gave me the age of my ears which exactly matches my age (57).

    I am a professor, and so my work requires me to speak loudly in class (thankfully not since Covid). I have read that this can accelerate hearing loss. My mum was also a prof, and she was hard of hearing in her later years. I am afraid that the same thing may happen to me.


    Thanks for the suggestion. I will do it this weekend.


    OK. Will do. Thanks.
     
  3. chervokas

    chervokas Senior Member

    Maxing out at 11kHz is not bad at all. I'm the same age and while I was good to around 16kHz a couple of years ago, I'm not down to 13kHz.

    I doubt any sense that your system's HF performance is off has to do with the 12kHz frequency spectrum and up. There's really not much musical content up there -- the high harmonics of cymbals and triangles and muted trumpets and such might have a lot of musical energy up there, but not too many other musical instruments do; and even if your hearing starts to roll off in that top octave, I'm not sure ones perception of the sound would be that the music would seem "muddy." Subjective impressions are all different, but I could imaging that it might sound a little less airy and sparkly but not so much "muddy." Furthermore, if you have age-related high frequency hearing loss, it probably didn't just fall off the table in the last two weeks, which is the period in which you said you've noticed a change. It is possible to have waxy build up in your ears to impact high frequency response, you could got to an ENT and have them checked/cleaned out, or even just try some Debrox or similar product. I've had the experience where I've spent weeks trying to troubleshoot a problem where the image of my stereo system was pulling to one side, particularly as frequencies when up. I tested everything sources, cables, tubes, room treatments. But it turned out the problem was waxy build up in one ear. I think cleaning the contacts is also a worthy thing to try. Also, using an iPad or and iPod, do you have any fine-tuning EQ options, you can try a little boost from 10kHz up and see if that makes a different (probably you're not deaf from 11kHz up). Like I said, I'm not sure that part of the spectrum is likely to be your problem, but it's an experiment you might be able to try via software.
     
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  4. Dennis0675

    Dennis0675 Hyperactive!

    Location:
    Ohio
    Multiple human lifetimes? Do you have some 200 year old capacitors that sound amazing?

    I will agree with you in that many times what people are doing is changing the voicing of their vintage equipment but caps do indeed go bad. It not a case of some audiophile transient snap that isn’t present but more likely the amp isn’t operational until a bad cap is replaced. I have found it to be more common that caps drift out of spec and can still limp along in old speakers. I’ve had a couple pair that are 50 years old that replacing the still operational caps absolutely improve the detail on the high end and removed a great deal of graininess from top to bottom. I wasn’t around 50 years ago to verify what they sounded like when new, I could have been revoicing vintage equipment but the change was so dramatic and better I can’t imagine anyone could hear what I was hearing and thought it was good. But I digress, caps can be tested. The values for new are known and it doesn’t take the golden ear of an audiophile tell if they are good or bad.

    I’ll bring this in for a landing by reminding everyone we are talking about a 17 year old Yamaha AVR. Wild guess but I’d say the replacement cost on eBay or CL is the $100 to $200 range? From a practical stand point, it is what it is. If you don’t like what it is, it can only be replaced. There is no case to be made for a re cap job unless you can do the work yourself.
     
  5. Oelewapper

    Oelewapper Plays vinyl instead of installing it on the floor.

    I don't know where you got that from, but a normal quality electrolytic capacitor lasts anywhere between 30 to 50 years (but already start drying out within 20 years).
    It depends on the quality of the electrolyte and if that's really bad, electrolytic caps can die very quickly, within a few years (like capacitors from the great capacitor plague back in the 00s).
    Solid capacitors like film and ceramic last very very long, while tantalum last shorter (more like 20 years).
    Plenty paper capacitors last very long as well, they're (still) commonly found in old tube radios from the 30s and 40s, most of those last about 50 to 80 years (more and more are finally failing in the last few decades, but it highly depends on usage).
     
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  6. Oelewapper

    Oelewapper Plays vinyl instead of installing it on the floor.

    Yeah, those Leyden jars sound amazingly sweet, as sweet as a jar of strawberry jelly! :biglaugh::biglaugh::biglaugh:
     
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  7. Dennis0675

    Dennis0675 Hyperactive!

    Location:
    Ohio
    The ones Jefferson was using at Monticello are still on display and sound lovely.
     
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  8. Oelewapper

    Oelewapper Plays vinyl instead of installing it on the floor.

    Also useful for lightning protection of your audio equipment, when connected to a kite!
     
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  9. Dennis0675

    Dennis0675 Hyperactive!

    Location:
    Ohio
    Kite capacitors give you an amazing midrange bloom
     
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  10. TarnishedEars

    TarnishedEars Forum Resident

    Location:
    The Seattle area
    This is true for many film, and ceramic caps. But it is not true for electrolytic, nor tantalum, nor paper dielectric caps. Most of the second group will begin to show signs of aging after between two to three decades, and perhaps as many as 5% to 10% of these will begin to fail within that timeline.

    But I don't think that this is the Op's issue. I think that hearing-loss is at work here.
     
    Last edited: Jun 11, 2021
  11. Helom

    Helom Forum member

    Location:
    U.S.
    That’s probably true for caps manufactured 40 years ago, though I’ve pulled 40+ year-old electrolytics out of electronics that still tested well within spec.
     
  12. TarnishedEars

    TarnishedEars Forum Resident

    Location:
    The Seattle area
    Same here. But these very old caps, even NOS caps, often don't last very long after that, if they are put back into service even when these initially tested fine in terms of value, ESR and leakage.
     
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  13. Boltman92124

    Boltman92124 Go Padres!!

    Location:
    San Diego
    I agree with the posts regarding doing a thorough cleaning. All RCA connections. All cable connectors. If you have bare wire speaker connections, trim them and get some fresh wire to twist. A grab of QTips and some of this stuff> Deoxit Gold G Series With Shop - CAIG
    You'll be amazed how much crud ends up on those QTips. I do this at least twice a year on every component/cable I use.
     
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