Empress Buffer+ Hum

Discussion in 'Effects, Pedals, Strings & Things' started by mannyprieto, Apr 20, 2015.

  1. mannyprieto

    mannyprieto Member

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    This is a new one. I've yet to do some in depth trouble shooting, but figured I'd ask here to see if anyone has had a similar issue before and could provide some pointers.

    I've got an Empress Buffer+ mounted underneath my board (a few inches to the left of my VL PP2+). I'm using the tuner out and it's my I/O interface basically. I haven't been using the boost feature at all since I got it, but i like the availibility should I ever need it. Yesterday I was playing my Jazzmaster and decided I wanted to push my amp a little and turn the boost on at about 9 oclock. Loved pushing the amp but it introduced the strangest electrical hum. It was throbbing/pulsing, not constant like cycle hum. Moving my physical location in the room seemed to make a difference in the loudness of the hum, but sometimes it would flare up regardless.

    At first I thought the boost was just making my single coil hum louder, but I decided to experiment with my compressor, using that as a boost and didn't experience the same problem. Not to mention that it wasn't present in any of my drives. When the boost feature is off, this particular hum is completely absent from my signal.

    Any idea what the problem might be?

    I should also mention that this hum was loud enough (unlike my regular single coil hum) that playing did not cover it. Even at full volume with loud strumming it was noticeable as an off key B drone underneath all my playing. (For the record I just turned the boost off for the set haha, but still would love to be able to use it in the future without that nasty hum)
     
  2. superdave2001

    superdave2001 Supporting Member

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    I'm assuming you're using the tuner out for a tuner, right? Are you using anything in the loop? What settings did you have the input and noise filter switches? And are you using the sag control knob on the side? Just trying to get full picture...because I've never experienced this with my Buffer +.
     
  3. mannyprieto

    mannyprieto Member

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    Yep. Using the tuner out for my Polytune mini 2. The loop has my entire pedalboard in it. Input and sag settings are standard (nothing) and the noise switch was at "little"


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  4. Adagietto

    Adagietto Supporting Member

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    Could it be another pedal in the signal chain? Pulsing implies a modulation pedal. A B-note drone indicates 60Hz AC (or rectified 120Hz) is getting in there somehow. That could mean a sensitive pedal is too close to the power supply transformer, signal cables are too close to AC cables, ripple on one or more DC outputs, or perhaps something else. Note that PP2+ outputs 5 & 6 can be noisy if set to 12V.

    Not sure why you'd hear it with the Buffer+ and not with the compressor.
     
  5. Glitch Magnet

    Glitch Magnet Member

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    I don't know if this is your problem, but I did discover on my Empress Compressor that the chassis is not properly grounded from the factory. IOW, the metal box is not tied to ground at all, so it's not providing good shielding. As a result, I'd get a bit of hum whenever I'd touch the footswitch or one of the toggles. I had to scratch off a bit of paint, wedge a wire between the box and bottom cover plate, and tie that wire to a ground point on the PCB. That fixed the problem for me.
     
  6. Glitch Magnet

    Glitch Magnet Member

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    Also, if you're using both stages of the Buffer +, you could potentially have a ground loop. A ground loop is a perfect antenna for picking up electrical noise. Hopefully the Buffer + is designed to prevent ground loops. I don't own one so I can't say if it is or not.
     
  7. mannyprieto

    mannyprieto Member

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    What do you mean by both stages?


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  8. Adagietto

    Adagietto Supporting Member

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    The 'stages' are the sections on either side of the loop. If not using the noise reduction, they could be considered independent.
     
  9. Glitch Magnet

    Glitch Magnet Member

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    Yeah, that's what I meant. Stage One is between the "guitar in" and "loop out" jacks, and Stage Two is between the "loop in" and "amp out" jacks. So, all I meant was, are you using it as it was designed, with your entire pedal chain in the loop?

    If you have all your pedals in the loop, it may be possible to create a ground loop if the grounds on the Buffer + are all tied together. As previously stated, a ground loop can create a big antenna for noise. On the other hand, if Empress lifts the ground at the "loop in," then that shouldn't happen.

    Another thing to consider, I learned the hard way that it can be important to run your cables close together on your pedalboard. More specifically, avoid creating a big loop around the board. Better to send and return your signal along the same physical path. Any deviation can create the dreaded "antenna for noise," even if there's no ground loop per se.

    Sorry. I know this is bothersome, low-level detail stuff that one would hope to avoid. But this is stuff I've gone through with noise problems myself. Hopefully your situation is not so complicated.
     
  10. Adagietto

    Adagietto Supporting Member

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    Mine is quiet, no ground loops. I've run two separate boards with different supplies in the loop, no problems. Manny still hasn't commented on post #4.
     
  11. mannyprieto

    mannyprieto Member

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    I do have a modulation pedal (chorus) in the loop, with output on the PP2+ set to 12V. The pedal was off when this noise was happening and again only when the boost was engaged, but I will experiment this week with removing that pedal from the physical location and from the loop altogether to see if that helps


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