How long do amplifiers last

Discussion in 'Hi-Fi and General Audio' started by ne5, Feb 9, 2021.

  1. ne5

    ne5

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    I have an old Rotel amplifier.

    Allowing for my ears, which aren't what they used to be, I need to use a hearing aid when I watch TV, my old 26 year old Rotel amp has, even in the last few years, not sounded the same.

    If I put my beyerdynamic dt770 headphones on, they sound absolutely great, but try as I might, and I also use an equaliser now to tweak the amp, I just can't get it sounding right, the vocals are too thin, or the bass is too deep and pronounced, or cymbals etc are too tinny, if I use the amp and my KEF Q 300 speakers.

    Should I, or do I, need to change the amp. It matters a lot, it will be real blow if my ears are so bad I can only listen to music properly with headphones.

    I don't mind in the slightest if I have to buy a new amp, and if this is the case, what do people recommend.
    I hate music that has boomy bass, or too heavy, I like to hear the tune, and the singing, and instruments. My collection is all sorts of rock and pop, from the Scorpions, Early Elton John, Cat Stevens, Moody Blues, Free, Greenday and a LOT of basic 1960's and 1970's pop music. It is all in mp3 as I stream it using a squeezebox.

    The only shop in Newcastle is Richer Sounds, other than Peter Tyson which is where I bought my speakers about 4 years ago and don't really do dems.
     
    ne5, Feb 9, 2021
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  2. ne5

    Sergeauckland

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    I can't comment on whether you should or need to change the amp, only on how long these things last.

    Firstly, an amplifier can last a very long time. There are enough Leak and Quad amplifiers from the 1950s and 1960s still working, that amplifiers can easily last that long. Many of these have been refurbished more recently, but many are still original. I have equipment here from the 1970s still with all-original parts, and still working to specification. My son has a completely original Quad 303 in near daily use.

    Excluding anything burning out, or valves wearing out, the most likely fault is that electrolytic capacitors dry out and need replacing. Very old carbon resistors also change value, so the circuit no longer operates as intended. Electrolytic capacitors have a rated life of something like 3-8000 hours at a rated voltage and temperature, and the lifetime is near enough doubled for every 10° reduction in temperature. So, for a capacitor rated at, say, 5000 hours at 85°, if it operates at an internal temperature of, say, 45°, then the lifetime can be reckoned to be 80,000 hours, or 10 years on 24/7, or 110 years at 2 hours a day! In other words, a very long time in normal domestic use. There are other factors that will shorten lifetimes, like being subjected to over-voltage, or indeed no voltage, but temperature is the most noticeable.

    I mentioned carbon resistors above, these were commonly used in the 1950s and early 1960s, and by now may be out of specification, but since the 1970s, resistors have been much more stable. I bought a set of 100 of each value 5% resistors in the very early 1970s, and I still have most of them left, and all are still comfortably in specification. Ditto with semiconductors, my 1970s stock of transistors are still fine, and will see me out.

    Returning to your problem for a moment, I think it much more likely that the issue, if it isn't you, is the loudspeakers. What loudspeakers did you use before the KEFs? How were the KEFs when you first got them? Has anything else changed? How are the loudspeakers positioned, stands? How far from a wall or corners?

    Hope some of this helps.

    S.
     
    Last edited: Feb 9, 2021
    Sergeauckland, Feb 9, 2021
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  3. ne5

    ne5

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    Before the KEFs, I had an old pair of JBL 100s, and they were old, I had them for about 25 years. They were also re furbished with new rubber and foam surrounds after the originals had perished, but as the sound had gradually detoriated over the years I had not noticed.

    They seemed to lose impact and quality after the refurbishment, so I gave them to my brother and he did a few tricks with them as this is a hobby of his, and I bought some Monitor Audio speakers which I wasn't happy with, then got the KEFs and immediately noticed a difference.

    However, at this stage, about 5 years ago, I wasn't aware of how my hearing was fading.

    When I got the hearing aids, everything was much better, I only use one of them but the tone is still too sharp and sometimes shrill.

    Even allowing for the hearing aid, it still means I want a speaker amp combination that I like, the headphones (without the aid in) are great, as are a lighter set of headphones, beyerdynamic DT231 galactica. These are much better than my speaker and amp combination. But I use the headphones with my tablet, all my listenable collection is on an SD card.

    And the KEFQ300s are very highly rated speaker, I listened to them before I bought them in Richer sounds, albeit with their own Cambridge amp and they were the ones I liked the most.

    My living room is standard size, I suppose, I have the speakers on stands at one end in front of a bay window, and sit at the opposite end of the room in the middle of them. They are not too close to the window, or a heater in front of the window.

    All my music is mp3, I use a squeezebox and the entire collection is digitised now.
     
    ne5, Feb 9, 2021
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  4. ne5

    Sergeauckland

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    It sounds like you're doing the right things. Having said that, it might be that the amplifier is somehow faulty, so you could try another amplifier, but my suspicions are still on the 'speakers unless your hearing problems are the cause. Listening on headphones is a very different experience even for anyone with 'normal' hearing, but if your hearing is impaired, then it may be that headphones work better for you.

    Just an aside, and nothing to do with the present thread, but is there a reason why you have digitised your music as MP3? I use a squeezebox too for most of my music and all my radio, and I have everything as FLAC.

    I'd be very happy to check your amplifier for correct operation, but sadly, we're not local to each other.

    S.
     
    Sergeauckland, Feb 9, 2021
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  5. ne5

    ne5

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    I started digitising a long time ago, and never really thought of flac, probably didn't even know about it and hardly seen anybody using it.

    It would be a MASSIVE job to do it all again, even if I could convert everything downwards from WAV. I suppose it would keep my busy while we are in lockdown.

    To look at the size of the job, and space (which is a consideration but not a problem as I would find a way using portable hard disks etc) I've got approx 80gb of mp3 music, 21500 files.
     
    ne5, Feb 9, 2021
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  6. ne5

    Sergeauckland

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    Yes, I do understand. When I first started digitising my music, MP3 was all there was, so when lossless came about I decided to redo everything, but only had a few hundred CDs to redo. Now there are a few thousand, and it's a recurring nightmare having to do it again, which is why my main hard drive is backed up to another locally, and a third I keep off-site in case of fire or flood. It would be bad enough to lose my home to a fire, but to lose my music as well...

    I can't do anything about my several hundred LPs, and I've recently started using Spotify, as LMS now integrates my local hard drive library with Spotify. This bothers me that any of the albums I have saved could disappear at their whim, so I'm still buying those CDs I would hate to be without. Still, Spotify is a great asset as it stops me buying CDs that subsequently I don't play much.

    Anyway, enough of my rambles, hope you get your loudspeaker issue sorted.

    S
     
    Sergeauckland, Feb 9, 2021
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  7. ne5

    ne5

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    how noticeable would the difference in quality be ? I have sold a lot of my LP's and turntable, I copied a lot of them straight to CD as WAV files (and still have them boxed away), so I could do those, but I have a lot which are also mp3 in origin, so copying them up isn't such a good idea is it ?

    I share your fear about your music collection BTW :D
     
    Last edited: Feb 10, 2021
    ne5, Feb 10, 2021
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  8. ne5

    Sergeauckland

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    The difference between mp3 and WAV or FLAC depends mostly on the bit rate of the mp3 and your acuity of the degradations caused by the bit reduction. At 320kbps, it's very unlikely to be audible, at 128k quite possible , although I can only hear that if I listen hard and I can compare with the original. But then, all my audio training was done long before digital audio was invented, so I was trained to hear distortions, harmonic and intermodulation, hear wow and flutter and various other issues of analogue audio, but not the artefacts of mp3 and the like.

    Now, I can happily listen to most mp3s without being aware of any issues. I use FLAC because storage is cheap, and I can be sure of no degradation even if I can't hear it. I also found that my earlier players couldn't handle gapless playback of mp3s on albums like Dark Side of the Moon, or long symphonic movements like Beethoven 9th, 4th movement that some CDs separated into sections that mp3 treated as separate tracks.

    If your mp3s are at 256k or 320k, then I wouldn't bother to rerip, but probably would for 128k.

    S
     
    Sergeauckland, Feb 10, 2021
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  9. ne5

    ne5

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    thanks mate, thats an easier solution. I've always tried to rip them at 192k minimum, or looked for that as a minimum if I've found it online or somewhere..... I suppose I could go through them and do some again at 320k, its easy enough and just right now have plenty of time.

    Its the tone of the music that I listen to the most, I would say, if it improves that I definitely would. I think I'll do a couple just to see if I can detect any difference.
     
    ne5, Feb 10, 2021
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  10. ne5

    ne5

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    Well, sorry for not mentioning earlier, but I have had a 2nd hand amplifier boxed up that I bought about 18 months ago on ebay. I hadn't really gave it much thought, as I thought it was probably my ears and I was ready to shell out money on a better new amp, or resign myself to using headphoes. This amp is the same model as the one under scrutiny, I bought it as a spare because I had liked it so much and when I saw it on ebay took pot luck and got it.

    Anyway, I wired this spare amp into the system today, and I'm gobsmacked.

    The difference immediately, was on a par with when my brother refoamed and refurbished the JBL speakers.

    Absolutely amazing, the singing and tone was better, bass was separate and clearer, the shrill ness which is partly my hearing aid has almost gone, I've been through a big cross section of my music files and everything sounds like it ought to, the best its been for a long time.

    I'm very pleased, I don't know how new this amp is, but I now know that if it seems to depreciate in future what to look at first, as the KEF speakers are only about 4 years old, but it all sounds as good as new.

    As Sergeauckland said, it seems now that the caps or something must have burned out due to age. Whatever it was, its sorted out I've no desire to meddle on with something that I like again.

    So for now I'm going to do nothing. Thanks to everybody for the help and please accept my apologies for wasting anybodys time.
     
    ne5, Feb 14, 2021
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