Replacing tubes immediately?

Discussion in 'Amps and Cabs' started by Gasp100, Apr 25, 2008.

  1. Gasp100

    Gasp100 Silver Supporting Member

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    Is it common place to just expect to have to replace tubes, even on almost new gear or gear that was just refurbished (supposedly?). The Winfield I bought a few weeks ago was just not sounding right and had some tube rattle issues (which I kind of fixed with tube dampeners). But, I decided to pay the expense of sending it to get thoroughly reviewed and I have a feeling the tubes (mainly the EL84's) are at fault (might be bias issues, I don't know. They were brand new JJ's <still in the original sealed box>.
    Today I got my refurb'd Vox AC15 handwired head and was playing it for a few hours on lower volumes. A couple of pops and clicks, nothing major. Now on the EF86 channel AND the top boost channel in pentode mode (full 15w mode) and pretty loud the volume clearly cuts out badly in and out. Also, when I switch back and forth between triode and pentode mode, sometimes it doesn't work at all :BOUNCE! Major hiss and pops and clicks abound.
    Tubes again??? EL84's again???
    This is my second Vox AC15 handwired head (both refurb's)... maybe I'm just having bad luck with EL84's?
    I just feel like it's a little over the top to almost expect that you are going to have to buy all new tubes everytime you buy an amp. Thoughts? Time for Solid State ;)? AxeFX, take me away!!! I'm going to try and stick with the Vox though, I really dig the tones.
     
  2. blackba

    blackba Supporting Member

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    I have replaced tubes on new amps, even when they are good. Often new production amps are shipped with tubes I don't care much for the sound of.

    EF86 tubes in general are not the most reliable. I would look for a NOS one. For EL84's, the Vox AC15 and AC30 amps are tough on those tubes as well.
     
  3. Gasp100

    Gasp100 Silver Supporting Member

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    I did pull the chassis (kind of a PITA) and reseated each tube and I also put tube dampeners on the EL84's because there were some microphonic overtones I attributed to the EL84's (but that was just a guess). They don't hurt anything, so why not?
    I also noticed the EF86 is in a "tube sock"(?) Basically, the tube is in this grey rubber covering the entire tube, apparently to dampen and cut down on microphonics (I know, EF86's are notorius). So, it might be a bad tube or it might not. If it was only the EF86 channel I'd suck it up and just get a NOS (which can run from $40 - 100 :( But, it's in pentode mode on the EF86 AND the Top Boost side.
    I called Musicians Friend, they started by telling me to call Vox for help... uh, no... I talked to the reps manager, they are exchanging the refurb'd one for a new one :rotflmao
    :agree
     
  4. bosstone

    bosstone Member

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    If you are having trouble with a brand new amp, you deserve warranty replacement or repair for free. There is absolutely no reason why the amp shouldn't work perfectly at day one...no excuse at all.
     
  5. packermann

    packermann Member

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    I agree with bosstone. It should work right if it is new. The other thing you should do is find a good tech by you who has a stock of tubes and knows how to troubleshoot tube related issues. My tech has ended up locating the tubes that were issues is two amps of mine a replaced them. Problem solved at far less cost than a full set of new tubes.
     
  6. Gasp100

    Gasp100 Silver Supporting Member

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    Yep, this is the last shot for Vox for me -- I figure it's a win/win being that I'm going from refurb'd to brand new. But there is always the chance the next one can be a dud too. If it comes in lame, I'm going to do some tube swapping if need be, but I'm not going to go crazy. I do need a good tech (with a reasonable bench fee :) that can troubleshoot tube issues for sure.
     
  7. hamfist

    hamfist Member

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    The problem sounds like it could well have been the rectifier tube crapping out. The current production rectifier tubes really do have an appalling record for reliability in Vox AC amps. They can die almost instantly. A NOS one will not make the amp sound better, but it should last many, many years and turn it from being an inherently unreliable amp to a reliable one.
    If you end up keeping your replacement amp, then my advice would be to put a NOS rectifier tube in straight away, along with a NOS EF86 (Dario Miniwatts were my favourite). I found the EL84's and the 12ax7's pretty good in the Heritage amps (although old tubes will, no doubt, last longer).
     
  8. Gasp100

    Gasp100 Silver Supporting Member

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    Yeah, you have to see my Musician's Friend track record. Everything was returned. 50% of what I ordered had problems or was DOA. The is my second refurb'd AC15 HW with problems so I think they want to give me a new one to get rid of me
    :banana
    Fine by me, if it works I'll never bother them again!
    Assuming that new amp is in good working order I will still replace the EF86 and possibly the tube rectifier.
     

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