Electro-Harmonix HumDebugger

Discussion in 'Effects, Pedals, Strings & Things' started by EddieEzzborne, Jul 26, 2006.


  1. EddieEzzborne

    EddieEzzborne Member

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  2. ZJD

    ZJD Senior Member

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    So far it seems like it just takes the hum away from single coils. Hopefully it'll do more. I'm waiting to see.
     
  3. EddieEzzborne

    EddieEzzborne Member

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    Yeah, it wasn't clear whether it takes away other noises... but, how does it take away hum from single coils? Does it turn them into humbuckers, effectively (at least while it's switched on)?
     
  4. ZJD

    ZJD Senior Member

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    That's my guess.
     
  5. EddieEzzborne

    EddieEzzborne Member

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    Isn't that some kind of intensity switch?
     
  6. ZJD

    ZJD Senior Member

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    Looks like there's a stomp switch to turn the unit on/off and an intensity switch to select normal and strong operation. Looks like a small pedal overall.
     
  7. Memorex

    Memorex Member

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    Since most of the hum from single coils is 60Hz (and related harmonics like 120, 180, etc.), it's probably some kind of multi-band notch filter. With a 5-band 60Hz (and 120, 180, 240, etc.) notch filter, you could easily quiet most any guitar.
     
  8. TieDyedDevil

    TieDyedDevil Member

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    I suspect it's a comb filter. That's really simple to implement with a short delay. If you put the first notch at 60Hz, the successive notches will be at 120Hz, 180Hz, 240Hz and so on... Such a filter would kill the fundamental frequency of the hum and all its harmonics.

    If they're really clever they'll use a servo to find the fundamental hum frequency so it'll work on 50Hz and 60Hz power as well as not-quite-to-spec generator power. That'd be a really simple thing to do, too, if they make you run it from an AC wall wart.

    I'd have to go back and check again, David, but I think the claim is that it's not a "low-pass" (that's gotta be a typo in their copy - they'd have to mean high-pass) filter.
     
  9. g3rmanium

    g3rmanium Member

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    I'm guessing notch filters, too. Waves does a plugin that can do the same.
     
  10. jbro

    jbro Member

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    I'm not sure what to make of this device.. with the awful (IMO) demonstration it gets in that video it's hard to tell what exactly it's doing and how effective it really is.

    All he mentions is that it's not a gate or a low-pass filter (called a low-pass filter, BTW, because it lets the low frequencies pass through and attenuates the highs - so that would be the proper term for it). As for a notch filter or a series of comb filters... it seems unlikely to me that you'd be able to completely negate all the frequencies that "hum" resides in and still have no noticeable effect on the sound of the guitar.

    I'd love to see a better demonstration and some more info about this pedal.
     
  11. TieDyedDevil

    TieDyedDevil Member

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    Yah. Seemed like he had a problem with the foot switch.

    Actually, the fundamental frequency of hum is at 60Hz and the fundamental of the open string of the low E on a guitar is about 80Hz. Therefore, a high-pass filter (if it was steep enough) would kill the fundamental hum frequency while letting the guitar signal through.

    But that's an incomplete (and ineffective) solution. In the real-world you get not just the 60Hz frequency, but also the harmonics. So even if you kill off 60Hz, you've still got 120Hz, 180Hz, etc... all competing with the guitar signal.

    Well, a comb filter will knock out all the hum frequencies.

    I agree that a comb filter would have a noticeable effect on the guitar sound. In fact it'd sound just like a flanger without any modulation or regeneration.

    Me, too. That was an awful demonstration.

    We'll see soon enough, I suppose...
     
  12. jbro

    jbro Member

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    Exactly. I think we'll all agree that the majority of the hum/buzz we percieve with a single coil guitar primarily resides in the upper frequencies. This is why turning down the presence/treble knob on your amp or guitar effectively kills most of the buzz (along with most of the high end, obviously). A high-pass filter or 60Hz notch, in addition to missing most of the audible buzz, would also interfere with baritone or other detunings.. I'm very curious what type of technology is in this box.
     
  13. jlagrassa

    jlagrassa Supporting Member

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    Looks like a cool device! if it works with out degrading your tone that might be a big seller for them, I have to let my friend know about this he's a strat player.............. man I hate 60 cycle hum!
     
  14. abuloso

    abuloso Member

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    I work in a music shop and took one of these puppies out to play a few days ago. It does work. I'm not sure how but it makes adds more presence to your signal. It removes/tightens the bass up a little too.
     
  15. Uma Floresta

    Uma Floresta Senior Member

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    I've heard someone's clips - it definitely knocks out single coil hum, but at the cost of altering your tone pretty noticeably.
     
  16. jaywalker

    jaywalker Member

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    I picked one of these up about a month ago and I guess mine was a dud, it added a horible cheap delay/resonance to everything I put through it. It sounded like a bloody ring modulator with a flat battery. Totally unuseable.
    I'm waiting for it to come back from the service centre, I (will)use it in conjunction with a boss noise gate so I have twice as much silence as anyone else.:rotflmao
     
  17. Lucidology

    Lucidology Member

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    Please let us know if you like it when ya get it back...
    thanks ...
     
  18. gen-x

    gen-x Member

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    If anyone can post a picture of the guts, I can most likely tell everyone how they are doing their magic wand routine. Need to see the circuit though.
     
  19. Macaroni

    Macaroni Member

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    When these first came out, several TGP members bought them - I bought 2. All of them were returned because they are crap. Yes they do eliminate single coil hum when playing clean, but when using OD it's pure garbage as described above - absolutely unusable. Both my units displayed this problem no matter where they were in the chain, and all others had the same issues.
     
  20. mrt

    mrt Member

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    I have one. its only work with overdrive and distortion. I have a peavey XXX and on the distortion channels is works wonders!! Its great for recording, or if you have a bad ground somewhere. it just kills it. any hum or buzz

    I just watched that demo. its weird, but it does just what he is saying.

    I'm selling mine, I got into rack gear. if you want make me a offer

    http://www.thegearpage.net/board/showthread.php?t=286994
     

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