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Clipping problems

Discussion in 'Amps and Cabs [BG]' started by S. Byrnes, Jan 16, 2005.


  1. I've been playing on a Fender Bassman400 combo amp that has a blown speaker. Even when the gain is at 2/3 and the volume all the way up, the amp clips. It didnt used to be like this but its getting worse, and I have tried other basses and use the active pad when playing. The EQ on my bass is set flat and the EQ on the amp is pretty flat with the lows cut a little and the mids boosted a little. Could the blown speaker make the amp clip or poor input connections be adding to the problem? Thanks
     
  2. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Why are you playing through a blown speaker?
     
  3. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    Yes, you'll get clipping when the gain is at 2/3 and the volume is all the way up, what do you expect???

    Replace that speaker, and turn your gain and volume down below half, and see if the clipping stops. I think you'll be amazed. :rollno:
     
  4. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    i saw that too and thought it might be a typo, it was 1:30 am so i decided to take another look at a decent hour - (i only got 2 hours of sleep sat nite/sun am after my sat gig and my kids kept me going all sun so i didnt feel qualified to type intelligently anymore - :p )

    yeah, that's a recipie for clipping and blown speakers.

    hey, ya never know. that cool sound geezer butler had on the original black sabbath album was due to him playing thru a cab with a blown speaker. i actually really dug his tone on that album.
     
  5. So am I just trying to get too much out of too little? I have had a lot of problems hearing myself and have had to turn it up like that to compensate.
     
  6. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    yes

    when using a bass amp that has preamp and master volume controls you'll get your max volume by 1st adjusting the preamp until it begins to clip/distort or when the compressor/limiter (if any) starts to kick in. Then 2nd you adjustthe master volume until it begins to clip/distort on your loudest notes and then backing off a bit. (on many amps this happens with both control in the 12 o'clock position). how you set your eq can casue the preamp or poweramp to clip earlier, (such as boosting the bass).

    im not sure what kind of speaker(s) your combo has. Many combos have an 8 ohm load for speakers and have a speaker extension jack that allows you to hook up another 8 ohm cabinet for a 4 ohm load (if the amp can handle a 4 ohm load). some combos have an internal speaker load (4 ohm or 8 ohm) that is all the poweramp can handle - you cant use any more speakers with it. a few combos have a 4 ohm internal speaker load and can safely drive a 2 ohm load, allowing you to hook up another 4 ohm cab or 1 or 2 8 ohm cabs to it for more volume. If your combo allows you to hook up another speaker cab to it you'll get more volume that way. (just be sure to verify this and use a cab with the appropriate impedance).

    it would help if you could give us the specs on the amp (# and size of speakers, what the net impedance of the internal speakers are, how much it puts out into 8 ohms, 4 ohms, and 2 ohms (if it can do 4 ohms or 2 ohms), if there is an external/extension speaker jack, (it might say something like "extension speaker-8 ohm minimum"), and the sensitivity of the cabinet protion of the combo is (it will probably be something like "100 dB @ 1 watt @ 1 meter @ 1 kHz"). If your owners manual doesnt tell you fender should be able to, or another person here may have one and know.
     
  7. Passinwind

    Passinwind I Know Nothing Supporting Member

    A blown speaker could do a lot more than just make that amp clip, it could potentially cook the output stage.:eek:
     
  8. Tritone

    Tritone Supporting Member

    Jan 24, 2002
    Santee, America
    +1 It's happened to me.......on a gig. :mad:
     
  9. Wow thats scary, will it cook the output stage if the speaker is still functional? I think the surround ripped or seperated so it sounds like I have distortion going.
    The amp is solid state and puts out 350watts at 4ohms. It has 2 10" speakers and a net 4ohms. It is only safe down to 4ohms, so an extension cab won't work. I'm thinking about replacing the current speakers with eminence neo's, I entered all the T/S specs into WinISD and they should work like the originals. There is a compressor on the amp that I have turned up all the way. It totally kills the lows but highs and mids come through ok, and the amp doesnt clip as much.
     
  10. Passinwind

    Passinwind I Know Nothing Supporting Member

    You'd do well to put a meter on those speakers, and be sure the impedance is actually still around 4 ohms. If a voice coil is partially displaced, pushing the speaker hard may make things even worse, and the failure mode isn't always predictable. With a solid state amp, the worst thing that could happen would be for a coil to short out. The amp "should" have protection built in, but an awful lot of the amps I've repaired have managed to fail in spite of that. If the problem is truly in the surround, a reconer could maybe fix that for you for fairly cheap. You also might find that just disconnecting the speaker in question gives better results than playing through it, if the second one is still OK. I'd almost bet that this would be the case, actually.

    Good luck, and try not to abuse your gear needlessly!


    --------------Charlie Escher
     
  11. The sound on the Sabbath album didn't use a blown speaker. Instead, they cut slits around the outer edges of the speaker so the speaker was free to flap around. That's still not good, there's better ways to get that tone!!
     
  12. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    didn't know that. i was just quoting what geezer said in his last bass player interview.
    either way, i'll stick to some sort of overdrive :p