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Vox AC30cc issues, ADVICE?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Senzu21, Jan 8, 2008.

  1. Senzu21

    Senzu21 Member

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    Oct 18, 2005
    Location:
    Central New York
    I recently bought a Vox AC30cc (December 15th) and have been really enjoying it. However, in the last few days it does not sound like it did before. When playing it sounds like someone turns the bass up all the way and then it returns to where it is set at, every few minutes. The amp has also got a rattle on certain notes, namely A or F#. I already replaced the stock tubes right after the holidays and thought maybe one of them were bad, but the stock tubes do the same thing. Do I give up on it and get a different one; I have a few days to return left? Give up on the custom classics and find something else? I already have $200+ in tubes, so its hard to decide.

    I have tried different outlets, guitars, cables, rooms...
     
  2. rog951

    rog951 Member

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    Jun 2, 2007
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    I've had a lot of problems with my CC too but all so far have turned out to be tube-related. The "bass turning up and down" thing sounds like a bad tube to me. Did you say it did that with both the old and new sets of tubes? You make it seem like you've replaced ALL the tubes, pre, output and rectifier, right? Keep in mind that new tubes are about as likely to be bad as old tubes, but the same exact problem with two completely different sets of tubes would be a bit of a stretch.

    As far as the rattle goes, is it a mechanical noise? Not much you can do but go around the amp and tighten every screw/bolt you can find. If the rattle bugs you and you can't track it down, by all means return the thing. Not sure what your level of experience with tube amps is, but it seems to me there's always going to be a little rattle or vibration noise or something. I usually fix it by turning the amp up loud enough that I don't hear it anymore! :D
     
  3. John Phillips

    John Phillips Member

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    Mar 17, 2002
    Location:
    Scotland
    Honest advice: this amp sounds quite good but is a service and potential long-term reliability nightmare. Even changing the tubes is enough to put me off recommending that anyone own one. Sorry... I wish it wasn't so, but it just isn't well-designed IMO.

    FWIW, the problem sounds more like a cracked circuit board joint (possibly in the tone stack area) than a tube problem.

    Maybe keep the good tubes and get a different EL84 amp.
     
  4. rog951

    rog951 Member

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    Pulling the chassis really isn't THAT bad, but my experience is with the head version only...the combos might be more of a pain. Still, I've often thought about jig-sawing some portholes into the top of the cabinet to make for easy tube access! IMO it's a crappy design to have to pull the entire chassis just to get to the tubes. Of course, it's the same physical layout as the originals so you can't really blame the CC's designers for that part of it I guess.

    The amp defintitely sounds quite good when it's working properly. I'm very happy to have mine back in top shape, but my experience thus far with it keeps me on edge. I'm always wondering what will go wrong next. As I said earlier, all my issues have ultimately turned out to be tube-related, but the amp still has a way to go before it earns my trust back.
     
  5. John Phillips

    John Phillips Member

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    In basic layout, yes - but on the originals you simply undo the four screws at the sides of the back panel and the whole thing slides out.

    On the AC30CC combo you have to take the panel off, get underneath the shelf where you can't see what you're doing, undo a lot of screws, two brackets, unclip some wires... it really is a pain.

    I have seen an original AC30 with a 'trapdoor' cut in the top, too... :(
     
  6. rog951

    rog951 Member

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    Wow. Glad I went the head/cab route! There are maybe 7-8 bolts/screws, but the chassis slides out pretty easily once the screws are out.

    One thing I really don't like is the flimsy gauge sheetmetal they used for the chassis. I believe they doubled it up in the area around the trannies at least, but when you pull the chassis out, the only thing you can grip is the thin stuff. Too much chassis flex going on during the process, and I shudder to think about how much flexture the pcbs are being subjected to. If they'd used heavier gauge material, they probably could've gotten away with less screws to hold it all in place. As it is, you really have to walk on eggshells a bit when handling the innards.

    A small price to pay though, to sound like God Almighty himself! ;)
     

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