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Hiss and hum

Discussion in 'Effects [BG]' started by Beav, Jun 30, 2007.


  1. Beav

    Beav Graphics Whore

    Jul 17, 2003
    Middle Tennessee
    Designer: Beav's Graphics
    For some reason my Aphex PF and Sansamp BDDI aren't too fond of each other and when they're both engaged I get a pretty bad hiss. I keep the PFs compression set at 3-4.5 and the output at around 6. The mix on the Sansamp is around 12:00-1:00. Then when I use my Jazz bass the noise gets a lot worse. When there's no signal running to the pedals, there's very little noise, but as soon as I plug any bass in, the noise starts at some level.

    I'm wondering if the EH Hum Debugger (or something along those lines) would help me out any, or if I'm just stuck with this noise.

    My rig is a Signal Flex adapter running - BOSS tuner, Rehoused Russian Big Muff, Dunlop 105Q Wah, Aphex PF and a Sansamp BDDI.
     
  2. bongomania

    bongomania Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    The first thing I'd do is try running them off separate power supplies or batteries. Certain pedals interact undesirably through a common ground.
     
  3. Sir Edward V

    Sir Edward V Not Actually Knighted... Yet!

    Dec 11, 2006
    Massachusetts
    could be the bass. are the bass's cavities shielded with copper or any other conductive material?

    My guitarist gets tons of noise when he has any distortion on. He has a fender Tele with no cavity shielding. I get nearly no noise with anything on, I have a ibanez bass, which IS shielded.

    and I'm not just making this up, this is a somewhat common problem. they sell kits to shield guitar cavities yourself incase the manufacturer didn't think it was needed to do it for you.

    try plugging in a bass that is shielded and see if thats the problem, ifit is then you should probably buy one o those kits and DIY
     
  4. Beav

    Beav Graphics Whore

    Jul 17, 2003
    Middle Tennessee
    Designer: Beav's Graphics
    Yes, they're both well shielded :(
     
  5. Beav

    Beav Graphics Whore

    Jul 17, 2003
    Middle Tennessee
    Designer: Beav's Graphics
    I tried them both off batteries and the hum was still very apparent.
     
  6. Sir Edward V

    Sir Edward V Not Actually Knighted... Yet!

    Dec 11, 2006
    Massachusetts
    tough cookies...
     
  7. I am very intrested as I think I have the same problem but no one responded to it....subscribing to thread.
     
  8. Compressors add noise. They also bring the level of all frequencies up [or down, depending on how you set it] - the idea being you have a max level that frequencies won't go beyond, but all frequencies will rise to. So if your bass has some minor humming [Fenders are horrible for this] your compressor will enhance the hum along with the other frequencies. Most cheap compressors use cheap opamps with low headroom that introduce hiss. So, if your compressor is before your Samsamp, the compressor will enhance the noise which the Sansamp will amplify. I say dump the compressor and most of this should clear up.
     
  9. Beav

    Beav Graphics Whore

    Jul 17, 2003
    Middle Tennessee
    Designer: Beav's Graphics
    I wish it was that easy. Unfortunately, I'm stuck with two issues if I lose the compressor. First, there's a much more drastic change in volumes when I swap basses. Second, my right hand dynamics tend to change (which on it's own is ok) and due to that it pushes the overdrive of the Sansamp too much. I basically have my "perfect" tone dialed in with the compressor running through the Sansamp.

    From reading the review of the EH Hum Debugger, it works for removing hum from basses too. Can anyone who has tried one out vouch for this?
     
  10. SpankyPants

    SpankyPants That's Mr. SpankyPants to you.

    Aug 24, 2006
    Brooklyn, NY
    The Hum Debugger is more for hum caused by single-coil pickups rather than a hiss caused by elevated treble freq's. I'd suggest the ISP Decimator over the Hum Debugger.
     
  11. Beav

    Beav Graphics Whore

    Jul 17, 2003
    Middle Tennessee
    Designer: Beav's Graphics
    Spanky, is the ISP a noise gate?
     
  12. SpankyPants

    SpankyPants That's Mr. SpankyPants to you.

    Aug 24, 2006
    Brooklyn, NY
    IIRC it's a downward expander, which is a bit different than a noisegate. You'll need someone with more EE knowledge than I to explain it any further. :p
     
  13. So, by that I assume that it's relatively quiet when one or both are bypassed?

    Noise, in particular hiss, is most often caused by excessive gain. Compressors are noted for it because they control gain over a wide range. Also, setting any pedal into overdrive will cause more noise (again, more gain = more noise) so perhaps you're compounding the problem by taking the increased noise from the sans amp and compressing it.

    I would suggest that you re-evaluate your settings to make sure you're not exacerbating the problem. Make sure you're not needlessly boosting (or attenuating) your signal at any point - ideally you should get roughly the same volume at your amp regardless of which pedals are active or in which combination. In other words, unity gain throughout.
     
  14. Beav

    Beav Graphics Whore

    Jul 17, 2003
    Middle Tennessee
    Designer: Beav's Graphics
    I'm compressing before I go into the Sansamp, but I understand what you're saying. After further tinkering, I notice there's very, very little noise before plugging in my bass. Where as with my distortion pedals, regardless if I have something plugged in or not, I still get hiss.

    Thanks for your advise, I'm going to test out the unity gain, which I believe will help me a little.
     
  15. That's odd. Normally you'd only get noise (hiss) from your bass if the treble controls are boosted. Is it an active bass? Changed the battery lately?

    Keep us posted.
     
  16. Don't rule out something as simple as shoddy cabling. I wired my rig with Mogami shielded cable to eliminate extraneous noise. Quite a bit of the cabling sold - especially the cheap stuff - adds noise to your signal chain.
     
  17. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    Mar 1, 2021

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