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Ashdown CTM-100 Problem

Discussion in 'Amps [BG]' started by Swampjam, Dec 6, 2013.


  1. Swampjam

    Swampjam

    Joined:
    Oct 5, 2013
    Hey guys I am desperately trying to find out whats wrong with my amp. I have been trying to contact Ashdown and they are simply not responding. I purchased the new CTM-100 all tube 100 watt bass amp, it sounds killer but when I am playing with my band I am noticing tube #1 is getting considerably hotter then tube #2. Is this normal for this kind of amp does anyone else have any experience with this. I feel hopelessly lost having just spent 1300 dollars on this amp and its already having an issue. If anyone could offer me any help or explanation it would be greatly appreciated.
     
  2. B-string

    B-string Gold Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    No it is not "normal", a 20 degree F would be normal. Most likely is an output tube drifted considerably after the matching was done (the one that is getting hotter). If you see any red glow at the tube sides (grey or black metal "cage" ) stop using the amp. Glow from the top and bottom are normal as well as a blue glow. That metal part surrounding all sides of the tube should not.
     
  3. Swampjam

    Swampjam

    Joined:
    Oct 5, 2013
    Thanks man, this amp has a built in bias adjuster, and the tubes are biased correctly. If I understand correctly one tube will usually get driven harder. The VU meter indicates that tube #1 is being pushed harder then the 2nd tube. I suppose it could be a problem with the tubes. Was just hoping its not a problem with the amp or a screen grid resistor or something. Don't wanna have to take a brand new amp to a tech already. Haven't even played it for 3 hours yet..
     
  4. B-string

    B-string Gold Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    The tubes should be driven the same. One is a push (or positive swing) the other is a pull (or negative swing) they combine in the output transformer to reconstruct a symmetrical sine wave if they are in balance. If one tube has to be driven harder to maintain that balance then it is weaker or the auto-bias is faulty. No fun having a new amp repaired but that is why you have a warranty, no one can predict if new components will fail in short order. The warranty takes care of you if one of those that was bought to build the unit fails unexpectedly. :)
     
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  6. Swampjam

    Swampjam

    Joined:
    Oct 5, 2013
    It's a little jewelers screwdriver in the back to adjust each tubes bias. I just hope it's one of the tubes mismatch or something. I would rage if I had to take it to a repair shop and pay more money. But that is what it looks like i'm gonna have to do :( I am starting to miss my solid state already.
     
  7. Daniel Piper

    Daniel Piper Supporting Member

    Joined:
    Aug 17, 2007
    Location:
    Taupo, New Zealand
    Is there anything funky happening in the tone of the amp? Unwanted distortion etc?

    That is a very Nic unit- I hope it comes right for you.
     
  8. B-string

    B-string Gold Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    Did you buy a used unit or from a non authorized dealer?
     
  9. Swampjam

    Swampjam

    Joined:
    Oct 5, 2013
    It sounds perfect which is why I feel like a dweeb complaining about something that sounds fine. I literally just jammed with my brother who is a loud drummer, 5 minutes ago sounded great. My ear pussies are cumming. Both tubes seemed to be the same temp this time. But the VU meter shows me that tube number 2 does get driven a little bit less. (Very minor) I purchased it from Sweetwater brand new. Authorized dealer.
     
  10. Swampjam

    Swampjam

    Joined:
    Oct 5, 2013
  11. B-string

    B-string Gold Supporting Member

    Joined:
    Nov 21, 2008
    Location:
    Lake Havasu City, Az USA
    If there is only a slight difference stop worrying, getting a stable exact match from New Production tubes is a futile effort. The quality controls and expertise are not there to be had. If you bought from Sweetwater a visit to an authorized tech cost you nothing but time. If the unit does actually fail within the first 30 days IIRC, Sweetwater takes care of everything with an exchange unit.

    The bottle shape looks like KT88s, a little stouter version of the 6550.
     

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