why is my amp distorting??

Discussion in 'Amps and Cabs [BG]' started by Eric Cioe, Sep 4, 2001.

  1. Eric Cioe

    Eric Cioe Supporting Member

    Jun 4, 2001
    Holland, MI
    i have a GK400 head thru a SWR 15 workingmans cab... its distoring, with the gain and volume at about 4. why???
  2. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Saint Louis, MO USA
    There are only about 1,000 reasons it could be distorting. Where the knobs are may not be relevant.

    Is your bass active? If so, check the battery.

    Are you sure it isn't the cabinet?

    Are you using a quality power source?

    Are you using any sort of preamp that may be significantly overdriving the preamp stage?

    If can answer all of those questions logically and still are having problems, take it to a tech.
  3. Luis Fabara

    Luis Fabara

    Aug 13, 2000
    Ecuador (South America)
    Audio Pro - Ecuador
    The GK 400RB produces only 150 Watts at 8ohms..
    So your amp might be clipping.

    150 At least for me, its not enough for most aplications.

    The SWR1 1x15 has an efficiency of 100dB wich is not bad at all, but maybe the volume you are getting is the max for it.

    Also, more bass = more power compsumption... so check that.
  4. CrawlingEye

    CrawlingEye Member

    Mar 20, 2001
    Easton, Pennsylvania

    I think he might be clipping, possibly blown a speaker, or if it isn't distorting very badly, it might be your bass? My Ibanez gets a naturally ovder driven sound. It might also be your pregain being up high? If I put my pregain to about 8 on my head, I'll start to distort.
  5. Eric Cioe

    Eric Cioe Supporting Member

    Jun 4, 2001
    Holland, MI
    blown speaker...ouch. how much to replace?
  6. CrawlingEye

    CrawlingEye Member

    Mar 20, 2001
    Easton, Pennsylvania
    I suggest reconing?
  7. Call SWR at (818) 253-4799 Adrian will give you a price for recone or replacement.
  8. jasonbraatz

    jasonbraatz Supporting Member

    Oct 18, 2000
    Milwaukee, WI
    if it distorts at lower volumes, then it's probably a blown speaker.

    if it only happens when it's loud, and you're not clipping anything in the preamp gain stages, it's probably your poweramp clipping.

    careful - poweramp clipping will blow speakers. ask me how i know :(

  9. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    I've used a 400RB from 1993 for about a year. It never distorted, but then, with some settings, it could.

    Set the input gain below 12 oc'clock. Set the boost to 12 o'clock. Set the master to 12 o'clock. There should be no problem with distortion unless you're using a bass with a preamp that has lots of gain. If you need to be louder, boost the master rather than the input gain or the boost.

    Manuals for GK amps are available at gallien.com, too.

    Good luck.

  10. CrawlingEye

    CrawlingEye Member

    Mar 20, 2001
    Easton, Pennsylvania

    If you turn your pregain up a lot, it'll distort also... Regardless of the volume. :)
  11. Nikehawk

    Nikehawk Guest

    Jul 29, 2001
    Yorkville, IL, USA
    Ok, I have a Crate 100 watt combo. Ive been using a passive Ibanez into a bass multi fx pedal. Just recently it started to distort at low levels, kind of flapping noise on anything below the G on the E string and anything on the low B string. I thought it might have been the fx pedal and the fact that I had the low end boosted a little, so i set it flat. Recently, I bought a Carlo Robelli 6er with active pickups. I found that I got a lot worse distortion from the Carlo, and tried fooling with the settings. Even on a flat setting the amp distorts more than it used to. So, I replaced the 9V battery, and tried it, to no avail. Figuring it was the bass and the crappy pickups I tried my old passive Ibanez and found the amp to distort the same amount.

    1) I do not peak the amp, and the bass settings were barely boosted, and I only play this amp in my room to cds (aka not very loud). I used to use this amp for practice in my band and for shows, and it never made this sound. Does this sound like a blown speaker? Or does this sound like maybe I have weird settings?

    2) I tried my active Carlo on my Firebass II and 4x10, and it distorts when I pluck somewhat hard. My Ibanez does not distort on my Firebass. Is it possible that a weird active pickup setting could cause distortion, or is it more likely that the bass has pickups that are so terrible it can not handle any sort of powerful signal?

    Any help will be appreciated!