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Old 06-16-2019, 12:16 PM
T268 T268 is offline
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Default Strange Pop with a newly installed K and K

Hi all. I just used my Collings that just had a K and K pure mini in it at my church. Itís a 1/4 cord to an active DI and straight to a board via an XLR cable. Sounded pretty good with basic EQing. Iím running it through a Behringer Ultra DI100 via phantom power about 50 feet from the board. I noticed that if i was a little aggressive with my muting with my right hand, there would be a pop sound. Not as painful as if I yanked the cord out, but a similar sound at maybe 1/4 the volume. I was able to reproduce it by banging a little on the bridge. Nothing rediculous. Iím not an aggressive player. However, it took less force to reproduce it while playing vs only hearing it with a solid bang on the bridge. Quite irritating. In fact it distracted me to the point where I screwed up pretty substantially.

It wasnít a big enough deal that careful playing didnít cure, but obviously something is wrong. I tried changing cables to no avail. The DI was turned on. The ground lift was also on. I donít hear anything banging around like one of the contact points of the K and K was loose(although I havenít visualized the area directly).

I did inadvertently rotate the jack about a half turn when I installed a Music Nomad Acousti-Lok strap lock adapter. Although looking inside, it doesnít look like the wires are under tension. I suspect this isnít the problem.

The DI100 has 250k of input impedance. I know other DIs have 1 Meg. I did not mess with the -20 dB attenuation to see if that cures it.

Anyone have any ideas what this could be and how to fix it?
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Old 06-16-2019, 02:33 PM
Rudy4 Rudy4 is offline
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This can happen if one of the transducers is put in so it contacts a bridge pin. Stick a inspection mirror in the soundhole and verify that there's clearance between the disc edges and the closest bridge pins.
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Old 06-16-2019, 02:56 PM
T268 T268 is offline
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Other than finding shorter bridge pins(is that even a thing?), I assume that will require some surgery? Given that everything is glued on, Iím guessing it would be hard to remove all the glue. Perhaps a new pickup. I hope not.
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Old 06-16-2019, 03:08 PM
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Looks like thereís about 2-3mm space between the disc and the string end. Thoughts?
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Old 06-16-2019, 03:42 PM
RogerPease RogerPease is offline
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Kind of a long shot:
According to K&K the wires from the discs to the endpin jack must not contact the interior of
the guitar. Normally the wires are twisted to take up any slack and keep them suspended.

Is it possible that when installing the Acoustic-lok the wire got untwisted enough to touch somewhere?
Thumping on the bridge could be making them jump around. It would an easy to twist the jack again.
The wire should be under some mild tension.

Look inside again and make sure the wires aren't close to anything.

Hope this helps. _RP

Last edited by RogerPease; 06-16-2019 at 03:44 PM. Reason: typo
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Old 06-16-2019, 04:31 PM
larryjoh814 larryjoh814 is offline
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After recently installing a K&K in my Rainsong, I had that popping sound until I reduced the signal from the DI to the Bose S1Pro
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Old 06-16-2019, 06:12 PM
sdelsolray sdelsolray is offline
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Several years ago there were several reports of similar noise when the guitar was struck hard on or near the bridge with a K&K installation. IIRC, there was an explanation on the K&K website...something to do with voltage spikes?
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Old 06-16-2019, 08:58 PM
T268 T268 is offline
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Thanks all. Iím just going to call K and K tomorrow. Hopefully their customer service is decent. I inspected the inside and it looks like the wires are largely away from all the surfaces. The wires right out of the contact points with the bridge are fairly close to the bridge plate. I bent them down a little bit. I plugged it into my electric amp and thumped on the bridge with no pop. I donít know how that will translate to the PA run. Weíll see.
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Old 06-17-2019, 01:41 PM
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Quote:
Originally Posted by T268 View Post
Hi all. I just used my Collings that just had a K and K pure mini in it at my church. Itís a 1/4 cord to an active DI and straight to a board via an XLR cable. Sounded pretty good with basic EQing. Iím running it through a Behringer Ultra DI100 via phantom power about 50 feet from the board. I noticed that if i was a little aggressive with my muting with my right hand, there would be a pop sound. Not as painful as if I yanked the cord out, but a similar sound at maybe 1/4 the volume. I was able to reproduce it by banging a little on the bridge. Nothing rediculous. Iím not an aggressive player. However, it took less force to reproduce it while playing vs only hearing it with a solid bang on the bridge. Quite irritating. In fact it distracted me to the point where I screwed up pretty substantially.

It wasnít a big enough deal that careful playing didnít cure, but obviously something is wrong. I tried changing cables to no avail. The DI was turned on. The ground lift was also on. I donít hear anything banging around like one of the contact points of the K and K was loose(although I havenít visualized the area directly).

I did inadvertently rotate the jack about a half turn when I installed a Music Nomad Acousti-Lok strap lock adapter. Although looking inside, it doesnít look like the wires are under tension. I suspect this isnít the problem.

The DI100 has 250k of input impedance. I know other DIs have 1 Meg. I did not mess with the -20 dB attenuation to see if that cures it.

Anyone have any ideas what this could be and how to fix it?
Hi T268

I have a friend who drops his hand onto the bridge when he mutes, and the K&K overloads every time he does it. He finally went with an under saddle because he is a singer who plays, and always has a backup rhythm/lead, bass and drums (plus fiddle) and pretty much his guitar is for him not the audience.

Any bridge-plate transducer will overload with drop strumming, or drop muting with a lot of force. After 30 years of performing in public, and 20 years of it playing an under saddle transducer, he wasn't going to adapt his drops and mutes.


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Old 06-17-2019, 02:08 PM
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I use K&K and JJB pickups and both are sensitive to your hand hitting the bridge. The sound you're hearing isn't a component pop, but the sound of your hand on the bridge. The easiest way to eliminate this (other than changing your playing style) is to lower the preamp output and get your volume from the output of the PA. With my system, if I'm using my Baggs Para DI, lower the gain on the DI and increase the volume on my PA. If I'm playing through my Loudbox Professional, I lower the channel volume and increase the master volume. I know this doesn't sound like it will make a difference, but it actually does make a significant difference.
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Old 06-17-2019, 08:25 PM
T268 T268 is offline
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Thanks Gents for the suggestions. I emailed K and K. I took a pretty detailed video of the installed pickup. They seemed to think that everything looked decent, but they inquired about what DI I was using. The one I am using has 250k of input impedance. They thought that was low for my purposes. They recommended a different DI with better input impedance. Of course they were all too happy to suggest their DI. Ha! I do think itís worth trying another DI(which I can always return) rather than ripping off the brand new pickup in favor of another.

What is interesting is I plugged it into my electric amp and thumped pretty good on the bridge and no pop at all. Iím hoping a more robust DI does the trick.

Thanks again for everyoneís input.

-Drew
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Old 06-18-2019, 04:56 AM
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Quote:
Originally Posted by Goat Whiskey Picks View Post
I use K&K and JJB pickups and both are sensitive to your hand hitting the bridge. The sound you're hearing isn't a component pop, but the sound of your hand on the bridge. The easiest way to eliminate this (other than changing your playing style) is to lower the preamp output and get your volume from the output of the PA. With my system, if I'm using my Baggs Para DI, lower the gain on the DI and increase the volume on my PA. If I'm playing through my Loudbox Professional, I lower the channel volume and increase the master volume. I know this doesn't sound like it will make a difference, but it actually does make a significant difference.
Thanks for that bit of info Mick.
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Old 06-18-2019, 05:01 AM
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The advice that seems to make sense indicates that it is possible for the K&K to drive the first active electronics it is connected into clipping and it is that distortion that turns a percussive bridge hit into an irritating "pop". The direction to turn the volume down at the first DI/amp/preamp/effect seems logical. The K&K Pure Mini puts out a pretty high voltage output relative to other piezo SBTs.
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Old 06-30-2019, 11:47 AM
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Ok so, we’re making progress. Used the SB-4 that has 5 megohm of input impedance. The pop was still there initially. However, the sound guy dialed the gain down and raised the volume and viola! So thankfully it’s not the pickup. Prying the contacts off the bridge plate would potentially destroy them and would be a real hassle to boot.

The question is am I satisfied. It’s tricky because we’re moving to a new worship space in the next 3 months and it’s anyone’s guess if there will more impedance needs. If all the equipment remains the same, I suspect not. However, I can return the SB-4 for something that has 10 megohm impedance, and that should certainly get the job done.

If I go that route, does anyone have any recs on an active DI with 10 megohm impedance?
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Old 06-30-2019, 06:35 PM
Rudy4 Rudy4 is offline
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Quote:
Originally Posted by T268 View Post
Ok so, weíre making progress. Used the SB-4 that has 5 megohm of input impedance. The pop was still there initially. However, the sound guy dialed the gain down and raised the volume and viola! So thankfully itís not the pickup. Prying the contacts off the bridge plate would potentially destroy them and would be a real hassle to boot.

The question is am I satisfied. Itís tricky because weíre moving to a new worship space in the next 3 months and itís anyoneís guess if there will more impedance needs. If all the equipment remains the same, I suspect not. However, I can return the SB-4 for something that has 10 megohm impedance, and that should certainly get the job done.

If I go that route, does anyone have any recs on an active DI with 10 megohm impedance?
One mega ohm is often stated as the sweet spot for impedance matching a piezo transducer. That removes unnecessary loading of your signal and also reduces the R/C filter network that results from your connection cable and the source resistance.

Most people find going up from 1 meg input impedance is unnecessary, and the !meg acutally benefits the sound due to slight loading of the transducer signal.
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