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EQ question

Discussion in 'Amps and Cabs [BG]' started by DownCaster, Sep 1, 2000.


  1. DownCaster

    DownCaster

    Aug 22, 2000
    ok...i have a Laney BC-75 15' combo. I have found that whenever i try to turn up any of the sliders (from the total cut position) that i get a real distorted sound to my bass. is there any way that i can get rid of that distorted sounds? should i maybe buy a EQ pedal?

    any suggestions would be respected
     
  2. wreckall

    wreckall

    Aug 21, 2000
    well probably not. the problem is likely the laney speaker.
    I have a laney amp too that i use for practice in my room. and it sounded really distorted with any volume. so i changed the speaker to a ev force driver. now the amp sounds great. if you have any friends with a bass cab just try using the output on back of your amp to drive it and see how it sounds.
     
  3. It might also be the fact that you are gained up too high. If the Eq is in front of the powerstage, you might distort the signal when boosting.

    Try to reduce gain and see if that helps, if it doesnt, I have no idea.
    Good Luck!
     
  4. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Just a little background. In an amplifier, there are usually several stages of amplification. If you use an active bass, the first stage would be the preamp in the bass. If you turn it up to something above zero dB, you are amplifying the signal. Then the signal enters the amp, and is boosted again by the pre-amp. If you have cut/boost EQ, any frequency you have boosted adds amplification (so-called EQ gain). This can be significant if you have 12 or 15 dB of boost available.

    On the EQ, you should try to limit your boost to about 3 dB, and cut the undesired frequencies a bit. This will tend to result in an overall EQ gain of zero dB, which is desirable. (By the way, you also can have significant EQ gain in an active bass, with the same attendant problem, namely, overdriving your amp's pre-amp.)

    After your EQ is applied (usually) the signal goes to the power amp stage, where one or more tubes or solid state devices are ready to crank out your final sound. If the signal has been juiced up too much in the previous stages, it will overdrive the power stage, producing the characteristic crappy sound. Further it can damage your speakers.

    The solution is to consider how much amplification is applied at each stage of the signal path, and try to limit it to zero dB in the pre-amp stages, and get your power from the power amp stage. As Mesa Man said, turn down your pre-amp at first. Then set your bass and your amp's EQ. Turn up the power amp as high as you like it, then increase the pre-amp little by little for max volume. When the amp starts to distort, back off the pre a little, and see if you can turn up the main for more volume.

    Remember, a speaker can take only so much power before it distorts under any circumstances. One 15 should give you pretty good volume, but isn't going to be adequate to compete with a couple 100-watt half-stacks from the guitars. It may turn out that you just need more equipment. Hope this doesn't give you G.A.S. Good luck.
     
  5. Yes MunjiBunga, I guess you got it all covered there.. good indepth explanation. Couldn't have done it better myself. Hope he manages now to get it all right. Indepth is always great, too bad i am too lazy to write all.. :)

    Oh well, until then,

     
  6. DownCaster

    DownCaster

    Aug 22, 2000
    i have the Gain turned up all the way (i am in a band) and that was what distorted it. it sounds great at mid Gain. thanks you guys for the help. only thing is if i turn up the when i turn up the gain again (to practice with the band) it sounds bad again...but i guess that will do for now. hey is when we play outta a PA it will be fine.

    thanks again
     
  7. Ok, but where is your Master volume at? Out back? Is that at max too, if so then I would say you have got a too weak amp for your needs.

    Right, see ya!
     
  8. I tried one of those same combo amps at a local store and had one of the same problems. I'm just glad I didn't pick to buy that one.