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White noise/hiss in signal

Discussion in 'Amps and Cabs [BG]' started by Lonnybass, May 18, 2003.


  1. Lonnybass

    Lonnybass Supporting Member

    Jul 19, 2000
    Minneapolis by way of Chicago
    Endorsing Artist: Pedulla Basses
    Greetings,

    I had a gig this afternoon using my big rig with some
    newly added components - a BBE 482 sonic maximizer and
    an Aphex parametric equalizer (both rackmounted).

    I've noticed a good deal of white noise/hiss when the
    Aphex is engaged through the effects loop of my
    Alembic F-1X preamp. Even without radical gain at any
    frequency setting, there's definitely audible fuzz in
    the signal.

    My signal path is as follows:

    Alembic F-1x --- tuner
    I I
    (output) e/fx loop --- Aphex EQ
    I
    BBE
    I
    Compressor
    I
    Crown CE 2000 power amp
    I
    2 x Acme Low B2's

    Any advice for eliminating/minimizing hiss would be
    much appreciated. This is a super hi-fi rig and noise on top of the signal makes me very unhappy - Disengaging the Aphex from the effects loop is
    the only thing that has worked so far...which kind of
    eliminates the point of a parametric EQ in the effects loop, doesn't it!

    Looking forward to hearing your ideas.
    Lonnybass
     
  2. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    The BBE manual says to put it last before the amp. I would put the compressor first. Maybe try those changes out.
     
  3. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    The only way to fix this is to isolate the offending piece of hardware. Use a process of elimination. Start by pulling devices out of the chain one at a time until you notice the his has disappeared.

    Once you've dont that, deternine if the unit is faulty, or if it just prefers to slotted into a different part of the signal chain.
     
  4. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    It might be a gain structure issue. Where do you have the gain set on the power amp and on the preamp?
     
  5. Most likely your BBE is intruducing some hiss and the compressor is boosting it. I like to put the compressor between the guitar and the pre-amp or at least the 1st one in the effects loop. That was you've got a consistent signal all the way through.