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Tube rattle

Discussion in 'Amp Central Station' started by Collin D Plonker, Aug 25, 2020.

  1. Collin D Plonker

    Collin D Plonker Tele-Afflicted

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    I have a Vox AC-10 I play all the time. After about a year I noticed the tubes started to rattle. I bought new tubes, but still they rattle. I even put the O-ring type dampers on all the tubes.

    Is it possible there is something else causing the rattle? I understand combo amps are prone to this, but I didn't have this issue at first. It's annoying. Any sage advice for me?
     
  2. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    Sure - anything can rattle. Logos, tube retainers, handle, loose screws, speaker itself, other things in the room that you think are the amp.

    It's kind of a pain to troubleshoot - you just have to keep isolating things (aka, removing parts or making sure they don't vibrate) until you find the issue.

    It's also possible your new tubes have some rattle - just because something is new doesn't mean it couldn't have a problem, especially in the land of tubes.
     
  3. wabashslim

    wabashslim Tele-Afflicted

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    Try pressing the tubes down (or up) into the sockets while playing, gently. Use a rag to avoid unpleasant burning flesh smell. See if they quiet down while you're pressing. I've had a couple brand new 6V6s do this, I put in spring-type (Marshall?) hold-downs, didn't help. I exchanged them for non-rattlers.
     
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  4. kingvox

    kingvox Tele-Meister

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    I was using Herbie's Audio tube dampers. They're great. However, I recently replaced all the tube sockets in my old 5F2A with belton tube sockets and no longer have to use the tube dampers.

    Changing the sockets is a pretty easy job, and I would highly recommend it. I advise using masking tape around the wires. The sockets have numbered tabs, and you have to make sure you know exactly where every wire goes, e.g. red wire to lug 1, white wire to lug 2, green wire across lug 4/5, etc., whatever it is. It's easy, but it's time consuming.

    Wiggle the tubes just a little and see if they're completely solid or if they have some give to them. In my case, they felt almost totally loose. I used some lock nuts and stainless machine screws for the new sockets, and really torqued those down good. They will not budge even a thousandth of an inch anymore and the tubes are solid as a rock in the new sockets.

    My amp only has 3 tubes, so that went pretty quick. Labeling and desoldering all the wires and taking the old sockets out can take a while. But once you get your new sockets in it'll make sense immediately how to install them. Just make sure you do your research and check the size of the sockets. The chassis is punched for a particular size. The Beltons aren't "supposed" to fit into my Fender, but they fit just fine using some nuts to make up for the small gap when installing.

    Worked for me. Might be different in your case, but the difference in feel of the Belton sockets compared to the old ones was night and day.
     
  5. Askwhy

    Askwhy Tele-Meister

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    Could be anything, including something in the room that sounds like its coming from the amp. Tubes are actually pretty easy to rule out, get an oven mit and lightly touch each tube while playing the offending note (its usually one note or frequency that is the worst).
    Tighten all screws etc. You can press on different parts of the cab and see if anything changes it. Also playing the amp through a different cab can give you some clues.
    Combo rattle sucks, good luck, you need to be thorough and patient but you can usually figure it out.
     
  6. Les Paul lover

    Les Paul lover Tele-Holic

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    My experience too. A microphonic valve should be straightforward to isolate - tap test and single valve swap will reveal the culprit.

    I've found screws, washers (in between the speaker cone and spider!!), and random things in the room resonating in unison with certain notes or from a specific volume point. Those are harder to trace.
     
  7. tap4154

    tap4154 Doctor of Teleocity Ad Free Member

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    The foul-mouthed guy that made this video says that they come with really bad tubes that rattle. By the way I've never owned a Vox, I can't believe how hard it is to get to the tubes!

     
  8. Collin D Plonker

    Collin D Plonker Tele-Afflicted

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    Yes,. I have seen this video, and that guy should realize that not everyone wants to hear his mouth. I reject the bad tube argument, only because I took the Chinese tubes out and replaced them with Slovakian tubes. Besides, Chinese tubes are getting better. I checked for microphonic tubes. They are ok. So I tightened every screw and will retest when nobody is asleep in the house. I suspect the wire tube holders may be rattling on the top. Maybe I will put some kind of hi-temp grommet under the holder. I will also move it around the room and see if it's actually something else rattling.
     
  9. 3-Chord-Genius

    3-Chord-Genius Poster Extraordinaire

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    My AC10C1 had a rattling stock power amp tube. And yes, it was a poorly-engineered design with regard to tube accessibility.
     
  10. Askwhy

    Askwhy Tele-Meister

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    Man, didn't realize how hard it is to get to those tubes. What a hassle! Funny video, though. My advice was based on open back combo cabs with the tubes hanging down from the chassis and where you can poke around inside with pressure, etc. Not sure what to do on that one besides change the tubes and hope for the best.
     
  11. tap4154

    tap4154 Doctor of Teleocity Ad Free Member

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    I don't know if it would work in that Vox, but in my Pro Jr, after constant tube rattling issues, I put anti-shock silicone standoffs on the tube PCB and haven't had a problem since. I discovered that is was mechanical vibrations, transmitted though the cabinet to the tube PCB, which IMO acts like a drum head and magnifies the vibrations it gets through the stock metal standoffs. It completely eliminated tube rattles when I put the silicone standoffs on. But again, I can't see if they would work in the Vox.


    Before and after:

    PJ Tube PCB Out.jpg Silicone Standoffs PCB (720x1280).jpg Silicone Spacer close (1280x872).jpg
     
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  12. andrewRneumann

    andrewRneumann Tele-Holic

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    I found a use for my old looping pedal when it comes to finding rattles and buzzes. Put that rattling riff on repeat and go hunting with your oven mitt!
     
  13. tap4154

    tap4154 Doctor of Teleocity Ad Free Member

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    I just blew up a screenshot of the AC10 power tube PCB and I think you could use the silicone standoffs (looks like one at each corner). However, it would move the tube sockets up and the wire retainers on the bracket would no longer work. Probably wouldn't need them anyway, I don't use the spring tube retainer that came with my PJ. The holes in the metal bracket needs to be bigger than the tubes BTW. In the PJ they were.

    Vox Tube PCB.jpg
     
  14. Collin D Plonker

    Collin D Plonker Tele-Afflicted

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    Thanks everyone for the replies. After tightening everything up, I have seen to have eliminated the rattle. The whole circuit is screwed to the back panel, as you may know. I found a couple of these screws that were not snug. I suspect this was the cause of the rattle. Looks like it is good for now. Thanks again.
     
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