Changing of the guard

May 14, 2022
 by Paul McGowan

There's been a bit of kerfuffle lately about a video I made where I detailed my experience in changing vacuum tubes.

I do it often. As often as every 6 months on the main system. I do it because once replaced, new life is breathed into the music.

The resistance to my statement seems to have come from those that have the opposite experience.

That for them, changing tubes hasn't the same new life result and therefore is a waste of money.

They are probably right in their situation.

Unless you have exactly the same everything as me why would a different result not be the natural occurrence?

The right and wrong of something are only valid as they pertain to the situation in its entirety.

In identical circumstances, we'd likely agree.

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25 comments on “Changing of the guard”

    1. FR, I think Kevin tries…
      I’ve purchased from Upscale.
      Kevin may have trouble with getting out of his own way.
      Unlike Paul McGowan, he seldom calls bullshit on himself.
      And yes, I also am all solid state at this point.

  1. I had been very happy with my BHK Pre and Atmasphere OTL into Avantgarde horns. However, Paul’s video prompted me to check how many hours were on the BHK valves. It was over 2500 hours so I changed them out (Electro Harmonix).

    Oh wow what a difference! I guess I’d just got used to the system gradually losing a bit of life/sparkle/soundstage. So thanks for the prompt Paul!

    On a seperate note - how on earth does Paul keep coming up with ideas for his posts!

    1. Hah! Well, as far as coming up with ideas for the posts, it's a bit of a magic trick. My friend, Seth, convinced me of the power each of us has within us if we make a commitment. And that's the hard thing.

      By committing to writing one post each day, every day, and without fail, the universe just opens up a window and it works.

      The power of commitment.

  2. Yes unless you didn’t just make this experience with a special kind of amp and/or one kind of tube and in the following didn’t extend the recommendation to a general one, you’re absolutely right imo.

    I think the more important question in this case is, why does a certain tube or do various tubes in a certain amp noticeably suffer in a timespan where in most other amps or amp/tube combinations, tubes (at least NOS) just finished burn in and last another 5-10 years without noteworthy loss (acoustically and measurement wise).

    Did you also have to change tubes so often in your previous preamp (I don’t remember the brand)?

    In my preamp every input has its own tube, so it’s very easy to use different tubes and switch inputs to compare in a warmed up amp. In two previous tube amps I also used tubes for years without loss and I’m really listening for details.

  3. Danger, off topic!
    I didn’t want to let the day pass without mentioning today’s 66th Eurovision Song Contest held this year in Turin, Italy. It probably won’t mean much to American friends but strangely Australia has been in since 2015. Depending on your point of view it’s regarded as a fiasco, farce or fun, probably all three, and is famous for introducing ABBA to the world in 1974. For those interested in a bit of nostalgia please click the second link.

    If you like a bit of fun click this link, this year’s entry from Norway, ‘Give That Wolf a Banana’ by ‘Subwoolfer’, and check out those lyrics. It’s not a typical entry, but neither is it untypical. Enjoy, if you can.

  4. So if new life is being breathed into the music every six months, then at what point does the breath start going away? It has to be less than six months. Is the breath loss gradual or all at once? If you’re an artist hoping to get released on Octave Records then it may behoove you to find out the tube change cycle so that your mix reaches the approval cycle right after the main system tube change.

    If six months is the optimal tube change time for you, what about hours? 8 hrs a day times 26weeks = (assume a 5 day work week) = 1004 hrs. How many on/off cycles?

    The tube degradation seems rather fast to some. Is this because of the tube design, the manufacturer, or the circuit that runs it?

    I don’t see any kerfuffle…. I see differences of opinion based on experience and preferences. (Maybe a little feather ruffle?) 😀 ✌️

    As a side note, I quickly went thru the PSA site before hitting send… can one even buy replacement tubes from PSA anymore? I see I can get a tube puller still.

    1. No talk about tubes needing a few hundred hours to burn-in properly.
      Could it be that brand-new tubes sound crisp/clean compared to the
      ones that have been in use because they haven't had time to burn-in?

      1. Could be -may not be.

        Follow that logic and solid state needs burn in. A tube starts burn out upon the application of power.

        Sagging cathodes -
        One can draw human anatomical correlations to tubes with age increases.

  5. I think Paul's advice of putting new tubes in on some sort of regular schedule and then taking them back out if no improvement is heard is probably the most sensible solution to tube degradation issues.

  6. And we saw what you didn’t do there, Paul.
    Elegant sir.
    “… then if you hear no improvement, your system is not very revealing,”

  7. Changing tubes every 6 months to a year seems very premature in an input stage. I leave my tube preamp and dac on 24/7 and the tubes that were in it still tested strong after 3 years in my preamp. I did have some cheap current production Russian tubes that didn't last long. The ken rads I bought from Andy at vintage tube service still test strong after 3 years of 24/7, I just switched them with some new production Linlai elite tubes for a little variety.

  8. Years ago I made friends with an older guy in our audio club. He had decades of experience in the hobby. His father worked for RCA and he grew up playing with tubes. I believe later he was the first Audio Research dealer in PA, out of his home.

    When I met JT he scoffed at tube audio, saying every time you turned it on it had deteriorated somewhat from your last listen.

    But he loved to experiment, designing and building his own components. Shortly after making his statement about tubes he began building tube amps once again. The funny thing was after auditioning one or two of those he used only tube based amps and preamps for the rest of his life.

    RIP JT.

  9. I don’t like how this was presented in the PS Audio Forum. Like it was posted to cause confrontation. I feel like everything in audio there are always more than 1 solution to any given situation and I saw merit in both ideas.

  10. So let's talk tubes with just a touch ( not too much, just a touch ) of science. Audio tubes fall into three categories: Power ( output ), preamp ( input ) and rectifier. All tubes have a break-in ( burn-in ) period of about 20 hours to get them to preform optimally. Electrical data taken from tubes show that there is change in the data for the first 20 hours ( or so ) and then the data becomes steady.

    Using tubes causes some of the material in the tubes to be consumed. Thus all tubes wear out with use. Here are typical lifetimes for tubes in hours of use: Power 500 to 800, Preamp 2500 and Rectifier 5000.

    Many tubes have filament heaters in them that come on as soon as you turn the amp on. They are like a 50 watt light bulb. Just like any other light bulb they burn out after so many hours. Tubes should always be turned off when not in use for maximum useful tube life.

    To the best of my knowledge there are no power tubes in any of the BHK amplifiers. Using the data for preamp ( input ) tubes it would take almost 14 hours of use everyday to wear them out in 6 months.

    Paul, unless you are using your tubes 14 hours everyday it think what is more likely is that you find the break-in period sound of the tubes refreshing. If you like it that much you might try tube rolling to see if you can find a brand of tubes that gives you that more refreshing sound all the time.

  11. It would also depend on how much one listens to their system as to how much degradation had taken place in the tube. Sheesh you would think someone could make a tube that performs to peak level longer than 6 months even if used a lot. So much for burn in when it comes to tubes. More like burn out which is why I prefer transistors that burn in and sound better over time rather than worse. Is there a way to prove by testing that a tube has degraded to the point where a new one would improve the sound or is this entirely done on listening or just to be safe install a new one?

  12. Has any tube amp owners experimented with just unplugging all the tubes, cleaning their prongs with antioxidation cleaner, and then reinserting them to see if that also adds new life? It may have zero effect, but who would know unless they try it?

    Just unplugging and plugging back in the tubes should help clean the surface oxidation on the tube prongs and in the socket receptacles, improving the electrical connection.

  13. A while back Paul gave a tip for better sound...

    Take your equipment and unplug all cables. Then plug them back in. "It will make things sound better." I tried that not long ago. It worked nicely.

    Just maybe? How about unplugging all the tubes and then plugging them back in? That may give you "new life" in what you hear?

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