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K&K Rockabilly Fingerboard Transducer Placement?

Discussion in 'Rockabilly [DB]' started by ricobasso, Dec 6, 2019.


  1. bassburner

    bassburner Supporting Member

    Dec 8, 2008
    I would say in terms of sound they're both great. The Shadow does have the notch filter which is invaluable. However, there have been a few people (including myself) that have had problems with their tiny jacks crapping out.

    I've been trying to get a hold of someone at Shadow for a few months now and they never respond.
     
  2. ricobasso

    ricobasso

    Jan 18, 2007
    UK, South East
    dhergert, re velcro, do you have the hook side or the fuzz side on the fingerboard?
     
    Keith Rawlings likes this.
  3. Keith Rawlings

    Keith Rawlings

    Aug 3, 2019
    Yes - I’m interested to know too. I have mine adhered to the back of the fingerboard with that double sided tape; but Vic says we can use hot glue from a glue gun. I never thought about velcroing it.
     
  4. They are rather flimsy, yes. Luckily, I haven't had any problems yet.
     
  5. dhergert

    dhergert Gold Supporting Member

    Jan 17, 2018
    Blue Zone, California
    I have the fuzzy side adhered to the underside of the fingerboard, although from a functional standpoint I don't know if it matters.

    This is the heavy duty Velcro with the very sticky adhesive on one side for attaching to whatever... The hook side of the Velcro also had the adhesive, but I (intentionally) gassed it overnight in a sealed Tupperware container with 90% rubbing alcohol, after which the adhesive peels right off. So the outer (hooked) layer of the Velcro sandwich has no adhesive on it.
     
    Keith Rawlings likes this.
  6. Keith Rawlings

    Keith Rawlings

    Aug 3, 2019
    Interesting - I'll have to give that a try and report back. Thanks for the explanation.
     
    dhergert likes this.
  7. ricobasso

    ricobasso

    Jan 18, 2007
    UK, South East
    I've increased the maximum gain on my pre-amp by 6dB while cutting some bass.
    I've tried holding the pu against the back of the fb in all possible positions while slapping and tapping with my other hand (not easy).
    I've tried sandwiching the fb pu in velcro at the top, middle and end of the fb underside.

    None of these are anywhere as loud as when I scratch or tap the fb pu directly. I'm guessing I'm going to need at least another 10 to 12dB before the output comes close to the bridge wing pu.

    Does the K&K pre-amp have more gain on the fb pu channel by default?

    The K&K fb pu is flat... is it OK to bend it to fit the underside curve of the scooped out part of the fb underside?
     
  8. bassburner

    bassburner Supporting Member

    Dec 8, 2008
    No. That will screw up the piezo element. Is there a flat part of the underside of the fingerboard you put it on?
     
  9. dhergert

    dhergert Gold Supporting Member

    Jan 17, 2018
    Blue Zone, California
    As @bassburner has mentioned, piezo elements are basically fairly thin silica and they break under tension. So no, you don't want to bend it.

    I don't think so, because the K&K pre-amp really doesn't know which channel is going to be used for the FB pickup As mentioned, my K&K pre-amp EQ is set flat-high with gain at about 20% across both channels and with that setting I consistently have to set volume on the FB at least 10% lower than the bridge wing.

    One other thing that we haven't discussed much here is piezos and amps and impedance match. I've not discussed it much because I don't have a huge understanding of impedance to draw from, so I welcome those with better knowledge to speak up... But put simply in a way I can understand, most piezos' output impedance is around 1 megaohm which means they output a pretty small signal, one which can even be negatively affected by cable length. Many amps, expecting a stronger boosted signal, have protective input signal processing that naturally tries to reduce the signal even further. Because of that a pre-amp is often pretty necessary to at least boost a piezo's signal. The K&K pre-amp I'm using is rated at 1 megaohm input impedance, so it matches the common piezo signal impedance.

    I've driven my wing pickup very successfully without a pre-amp; I just didn't have as much headroom. But at that time my FB pickup wasn't working due to some hacked-wiring problems so I can't say how it worked without a pre-amp; I've since replaced the old pickup system -- which came to me with my DB -- with a newer one from the same company and of the same model. At that time, primarily in order to blend the wing and FB pickups I purchased the K&K pre-amp that I'm using now. Of course along with blending and all of its other features, this pre-amp does the impedance matching for the amps and/or FOH systems that I connect to.

    After everything you've tried, it's seeming clear that the problem you're experiencing is pretty different from most of our experiences with the various other FB pickups that we're using... I'm starting to think, as you suspected was a possibility early on, that the FB piezo itself that you're working with isn't working optimally. I haven't heard or read about this happening a lot in the past, so this is pretty unusual for a new piezo. Now whether your K&K is working as designed or not, it doesn't seem clear, but from everything I've read I doubt that their specs would have low FB volume baked-in this way.

    You've already done this to some extent, but since you purchased your FB pickup from him, and out of respect for him and for his excellent business ethic, I'd suggest talking with Mark Gollihur again. He visits TB/DB often and you can refer him to this thread. I really suspect that he can help you solve this issue.
     
  10. ricobasso

    ricobasso

    Jan 18, 2007
    UK, South East
    I will certainly contact Gollihur again.

    I thought the twin pickup K&K set used a stereo jack to connect both PUs to the pre-amp, in which case the two inputs could be dedicated and of different sensitivity.

    I’m swinging towards the opinion that the unbalance I’m seeing could be due to my use of an Ashworth bridge wing pu. The Ashworth pu is long and thin and constructed to work in a differential bending mode. Both sides of the bridge wing gap have to be carved to contact the two pu ends on one side and the middle of the pu on the other side. Vibration of the bridge results in a bending of the piezo. From what I’ve read, this results in a higher output than any other piezo mode.

    I will increase the maximum gain of the fb pu channel some more and report back.
     
    Last edited: Dec 13, 2019
    Keith Rawlings and dhergert like this.
  11. dhergert

    dhergert Gold Supporting Member

    Jan 17, 2018
    Blue Zone, California
    That could be the case if there was a wiring standard for stereo jack wiring to use for the wing pickup and the FB pickup. There isn't a standard for that though. Also, these are general purpose pre-amps, neither the K&K Dual Channel Pro or the ST model are limited specifically to servicing only a wing and FB piezo set. There could be any combination used, including dyn-mics, piezos, mags, etc.

    That sounds interesting... I hadn't seen the Ashworth pickups before. I guess it's possible that it is so much louder that it makes the FB pickup sound quiet.

    Best of luck, I hope it works better for you!
     
    Keith Rawlings likes this.
  12. ricobasso

    ricobasso

    Jan 18, 2007
    UK, South East
    This is what the man at K&K says
    "I suspect the pickup is not in full contact with the surface of the fingerboard, this is essential for good energy transfer and volume.
    The issue of low volume from the fingerboard pickup is not common and is almost universally associated with poor contact between the pickup and the wood."

    This says to me that mounting with velcro is never going to work! (obviously it does for dhergert)

    So, I'm on my own here. I get very little output whether I mount directly on the flat part of the fb with double sided tape or in the scooped curved part using velcro.

    Not being sure which way to go, I'm going to try the pickup on some pieces of scrap wood, all the same size, except different thicknesses. Then do some more tap tests on the fb extension and finally cut a smooth, flat, thinner area into the underside somewhere. Sounds like a plan but maybe it would be simpler to use a mic!!
     
    dhergert likes this.
  13. dhergert

    dhergert Gold Supporting Member

    Jan 17, 2018
    Blue Zone, California
    Hmmm, I'm amazed. But I'm glad you spoke with someone from K&K. Direct information is always the best.

    In the past I've been in contact a few different times with the man who designs and makes the pickup system I'm using, and he expressed pretty much the opposite about his FB pickups. He was aware of my use of Velcro and was pretty encouraging about using it if it worked, also including that hot-glue could be used instead of the 1/32" foam rubber-backed double faced tape that comes with his pickup.

    I think I mentioned this before, but my pickup system is from Vic's Pickups. It's a Model C which is a combined FB (Model A) and bridge wing (Model B) pickup system. I have nothing but the highest praise for the products and the service that Zac Victor provides (NFI). I'm also very successfully using the K&K Dual Channel Pro ST pre-amp (NFI), which was purchased through Mark Gulliher (NFI).

    To me the differences in these two FB pickup manufacturers' emphasis on mounting instructions potentially describes a major difference between the sensitivity specs that these two different FB piezo pickup systems are produced to meet. I'm not aware of actual tech-spec sheets being available from either manufacturer (speaking of tech-spec sheets similar to those available for microphones), but I'd sure like to see them.

    Edit: P.S.
    There is a lot of discussion lately here on TB/DB about using onboard mounted dynamic mics. It's another valid direction that is available and there is a lot of interesting and valuable research happening behind the scenes of the threads that are about this. If you're serious about this I'd encourage you to look at similar threads about this here in TB/DB. Just like with pickups, there are advantages and disadvantages with mics (both dynamic and condenser); one important consideration is extremely high-volume situations and feedback.
     
    Last edited: Dec 19, 2019
    Keith Rawlings likes this.
  14. 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.

     
    May 12, 2021

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