Ashdown ABM 300 C-110 hum

Discussion in 'Amps [BG]' started by BrynGwyntog, Jan 17, 2014.


  1. BrynGwyntog

    BrynGwyntog

    Joined:
    Jan 17, 2014
    Hi All,

    This is my first post on this forum so I hope you'll all forgive any transgressions.

    I'm pretty new to playing bass and have just bought a second hand Ashdown ABM 300 C-110 off eBay. The first thing I noticed when I plugged it in was that there was a lot of hum. The tone controls can reduce or increase the hum. The hum didn't change when I plugged in the bass.

    Then I noticed that the VU meter didn't so much as twitch when I played the bass. It's an active bass with a new battery plugged into the low socket (though I tried both).

    Sweeping the Input Mix doesn't noticably change the output which is nowhere near as load as I'd expect.

    I've removed the head and reseated the valve. There is the barest of glows from the valve.

    Anybody any ideas what might be the problem? I suspect the valve myself.

    Kind regards,

    Bryn
     
  2. Kapucheen

    Kapucheen

    Joined:
    Mar 13, 2013
    Hi,

    I have a 300w C115, original EVO and it has a hum. I bought mine second hand. The hum stops when you hit the mute button or disconnect the speaker from the amp. I tried checking the earth, changing the valve etc etc but in the end lived with the hum which you don't notice when with a full band. I had an electrician friend check the capacitors/resistors but there was nothing untoward.

    I've just got a second hand EVO III 500w head and it's silent other than the fans, which as others say are quite loud. That said, when I engage my effects board there's "noise", but essentially it is "silent".

    I just notice you were mentioning the "loudness". My 300w combo is at gig volume when the "input" is around 11-12 o'clock and the "output" is at 1 o'clock. This is with the EQ engaged and the bass, treble, mid, set at 12 o'clock and the sliders all in the middle position. The VU is hardly moving at this stage. I am using a J bass in the passive slot. To get the same volume level from the 500w head going through an ABM 115 300w cab I have to have the "input" at 3 o'clock and the output at 4 o'clock. The VU is flapping back and forth but not going into the red. Many people comment on how quiet the EVO IIIs are. I have had mine a week.

    Remembering that both amps will only be outputting halve their full capacity until another 8ohm cab is connected.

    Regarding the "glow" my valves have a very dim light at the very top of the valve when operating.

    Cheers.
     
    Last edited: Jul 21, 2014
  3. BassmanPaul

    BassmanPaul Gold Supporting Member

    Joined:
    Aug 25, 2007
    Location:
    Toronto Ontario Canada
    Pre-amp tubes don't glow that much. They're not like a light bulb. Sounds to me like you may have bought a faulty unit. You could take the amp to a tech or, if you can, return it and try something else.

    Off topic: Thanks Kapucheen for the best laugh of the day!! The hum stops when you disconnect the speaker was priceless. For everything else there's Mastercard! :D
     

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