Is it me or the Z?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by crowder, Feb 20, 2003.

  1. crowder

    crowder Guest

    Just got a lightly used Maz Jr. -- my first Z. Everything's just right except for a low hum in the output. Not enough to be a problem on stage, but enough to make it tough to record with. Not the tubes (swapped them all, careful to use a good matched pair of EL84's), not affected by any volume or tone controls, there with or without a guitar plugged in, there with the reverb tank unplugged. Pulled the chassis to look for anything obvious. Anyone else run into this? An old Fender in the same place, same outlet has no hum. Ideas? Thanks.

    Orin Crowder
  2. PerryR

    PerryR Silver Supporting Member

    Jan 4, 2002
    Richland, Wa
    First guess would be the EL84's aren't matched, but sounds like you know that they are?

    I'd suggest you email Z. Something may need repair.
  3. Artb

    Artb Member

    Jan 13, 2002
    West Coast
    My Jr. hums a bit too, but never loudly enough to be disruptive.

    I thought that was par for the course with these type of amps....

  4. decay-o-caster

    decay-o-caster Member

    Jan 4, 2002
    The Greater San Jose Metroplex
    Not trying to be a smart-ass, but could it be the cooling fan? The Maz38 Senior's fan is quite noticeable.

    Um, be careful if you unplug it for recording - don't forget to plug it in again afterwards!
  5. fjs1962

    fjs1962 Silver Supporting Member

    Aug 8, 2002
    The Jr's don't have the cooling fan. My Jr doesn't have any sort of hum. Did you try the rectifier tube?
  6. crowder

    crowder Guest

    Thanks everyone. That's right, no fan in the Jr. I tried two different sets of matched power tubes, Groove Tubes and EI's. I also replaced the rectifier with the same (a Sovtek). Wondering if it could be the output transformer or a bypass capacitor (now I'm getting beyond my knowledge). I did exchange a couple of emails with the Dr. He said he was sure it was the tubes and didn't really encourage me to send it to him (mostly trying to save me some shipping cost, I think).
  7. Jhigley

    Jhigley Member

    Jan 4, 2002
    Nitro, WV
    My Twintone was humming after I re-tubed turned out to be one of the pre-amp tubes..brand new one to boot.

  8. sws1

    sws1 Member

    Aug 19, 2002
    East of the west
    My MAZ 18 has always had a slight hum in it. Gets worse at the reverb is turned up. Thought it was normal. Z told me once before (via email) that is was normal.
  9. Shane S

    Shane S Member

    Jan 30, 2003
    Portland, Oregon
    My MAZ-18jr 2x12 has always hummed and humms more when the reverb is turned up. I haved played probably 20 MAZ-18's and everyone has hummed, but they all sound great. I never notice the hum when I am playing in a band situation.

    What I would like to know is if the non-reverb model hums??
  10. AlexT

    AlexT Guest

    Not sure if this makes sense - a few times last summer (high humidity!) my Maz 18 would hum as soon as I turned it on; the hum would disappear in a few minutes. I suspect that is somehow related to the paper insulation of the transformer - ??(Are you storing it in a damp basement?)

    Also, I noticed that, depending on the location, the reverb circuit picks-up some radio station - the amount depending on the reverb level. This could also be the cause of hum.

    BTW, none of the two issues above bother me at all.

  11. crowder

    crowder Guest

    Thanks again everyone. I'm getting the idea that what I'm hearing is pretty normal, although it's still a bummer that you can't really record at lower volumes without gating. But, as everyone probably knows, the tone and detail and bottom -- the whole Z thing - can quickly make you forget about that small imperfection. It really is quite an amp.

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