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Behringer/Avatar- big hiss

Discussion in 'Amps and Cabs [BG]' started by ron_a218, Apr 18, 2005.


  1. ron_a218

    ron_a218

    Apr 18, 2005
    I just bought a new rig, a Behringer Bx3000T and an Avatar 2x12 cab. I'm getting a very annoying hiss in the horn if its turned on at all. I read the threads on the crossover problems in these cabs but how do I tell if this is in the amp or the cab? If I get my bass close to the amp the level of hiss increases significantly. I know its not the bass cause I play through other rigs w/o this problem. Also on the amp the needle on the gain meter never moves. I've changed out the speaker cable but it made no difference. I can play an epi chet through the rig and the hiss is not noticeable making me think its coming from the pickups on the bass (Carvin LB70). I don't have another cab handy to check out the head but I figure thats the next step. If this is a problem with the head, I need to send it back in the next day or so (30 day return is nearly up). Thanks for your input. Ron A
     
  2. Jack

    Jack

    Sep 6, 2003
    Newcastle, UK
    Ill bet you its the head, or bad shielding on the bass.
     
  3. alibloke

    alibloke

    Dec 17, 2004
    Bristol, England
    Hi, what gain setting are you using at present?

    I had the same problem at first, because I've been used to setting the gain to 2-3 O'clock on my old Trace Elliot combo. Also, be careful about using the 'bright' function.

    The input gain on the Behringer's preamp is quite sensitive, I've found 10 to 11 o'clock normally suffices.

    Try turning your output dial to 0, and then adjust the gain on the pre so that the needle peaks just short of the red, when you hit the open E-string on your bass.

    Other than that, I have to say that I've also found the VU meter to be pretty useless! :rollno:
     
  4. ron_a218

    ron_a218

    Apr 18, 2005
    With the bass plugged into active and the output on zero, I can crank the gain all the way up and the VU meter will only move about 1/4 way. If plugged into passive then it will finally get to the red at about 4 o'clock. The bass is active, but when I plug into the passive jack I don't have to run the gain as high to get volume ( this seems backwards??) and you're right, turning off the bright switch removed most of the hiss. I get very little movement of the vu meter when the gain is at 10-11 o'clock, is this normal on this head? Ron A
     
  5. alibloke

    alibloke

    Dec 17, 2004
    Bristol, England
    I tend to use the 'passive' jack for my active EMGs for this exact reason.

    The 'active' jack isn't very sensitive. I think it is meant only for people who add alot of volume boost and EQ on their active basses.

    [edit]

    How does the gain needle respond to your Epi using the passive and active jacks?

    Another thought is that if the above doesn't work, and you are only experiencing hiss with the Carvin, have a quick look to see whether the connection for your bridge ground has come loose.
     
  6. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    The BX3000T doesn't have a signal-to-noise rating, so it could just be a noisy amp. It's also a powerful amp, so if it has (for instance) a signal-to-noise of 90 dB, and your speaker has a sensitivity of 100 dB/1W/1m, then you will get 34 dB of hiss under the best of circumstances. You would probably notice this in a quiet room with the tweeter turned on.
     
  7. dgce

    dgce

    Jun 17, 2001
    Massachusetts, USA
    Say, why not just contact Dave at Avatar. He's a friendly, helpful guy who definitely knows his stuff. Bet he could help.
    (208)762-5251 or avatarspeakers@imbris.com.

    r
     
  8. Stinsok

    Stinsok Supporting Member

    Dec 16, 2002
    Central Alabama
    I own two Avatar cabinets and the tweeters are "hissy" by nature. I rarely use them.
     
  9. ron_a218

    ron_a218

    Apr 18, 2005
    I get no hiss from the amp at all using the Epi Chet (piezo pickup) and it actually sounds great through this amp and cab.
    I get no response on the gain meter at all, with the gain all the way up in active and just slight movement in the passive jack.
    I did call Avatar and they said try out the amp on another cab and if its a problem with their horn they would gladly replace the horn. I didn't have another cab handy but plugged into a 8 ohm floor monitor and got the same hiss with the bass. I can Eq most of the hiss out by turning off the bright switch and and turning down the gain levels as earlier suggested. I guess most of it just going to be the learning curve of getting to know this amp and possibly noisy pickups in the bass (even though I never noticed a hiss through the other amps I use, Fender bassman 60 and Ibanez Sw65 or playing direct through the board). Thanks for the help,any other suggestions are greatly appreciated. Ron A
     
  10. I had hiss with the original Single cap 6db crossover for the horn, however when I made a 4th order 24db crossover most of the hiss is gone. Another way to get rid of some hiss is to use an Equalizer that has at least a 10Khz band adjustment and put that all the way down to kill hiss without effecting the sound of your bass hardly at all. Between the new crossover and the EQ I have no noticable hiss.
     
  11. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The source of the hiss is the amp. It's noise caused by the amps own circuitry and can be quite pronounced with a speaker that is sensitive to high frequencies, such as one with a tweeter. If the amp has separate input gain and output volume controls you will minimize the noise by running the input gain high and amp volume low. If there is an active and passive input use the passive. The root cause of this noise lies in the quality of the components used in its construction (the technical terms are resistor noise and semi- conductor noise) and there may be nothing that you can do about it.