Noise on K-Mod using both inner coils

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Noise on K-Mod using both inner coils

Postby Cue Zephyr » Thu Mar 01, 2018 2:51 pm

Howdy folks,

I had my tech K-Mod my Tribute L-2000 with this schematic, because it was the clearest:
https://drive.google.com/open?id=1GJo0t ... oZWfFMrNDR

I went with the 4PDT on-on-on switch and the middle position uses the inner coils.

Great tones, but I'm having some noise issues on the new setting, especially in active. All the original pickup settings are still quiet.

Now my tech reported that he didn't let the positive 9V go over ground because it wouldn't produce sound otherwise.

Now I'm not exactly sure what it means, but maybe one of you does.

At first I thought maybe the separate inner coils from the two pickups aren't hum-cancelling, but somebody on TalkBass assured me they are.

I could make a recording of the noise if it helps you figure out what the problem could be.

Thanks.
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Re: Noise on K-Mod using both inner coils

Postby Ken Baker » Thu Mar 01, 2018 3:07 pm

Cue Zephyr wrote:Howdy folks,

I had my tech K-Mod my Tribute L-2000 with this schematic, because it was the clearest:
https://drive.google.com/open?id=1GJo0t ... oZWfFMrNDR


Not a single coil circuit. Stock L Series circuit. It can be used as a basis for a single coil mod for everything except the coil select switch.

I went with the 4PDT on-on-on switch and the middle position uses the inner coils.

Great tones, but I'm having some noise issues on the new setting, especially in active. All the original pickup settings are still quiet.


If the tech reversed polarity on one of the inner coils, you will be hum additive. If he/she does it right, the two coils will be hum canceling if both levels are set equally.

Now my tech reported that he didn't let the positive 9V go over ground because it wouldn't produce sound otherwise.

Now I'm not exactly sure what it means, but maybe one of you does.


Why did the tech even mess with power? NOTHING should have changed there.

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Re: Noise on K-Mod using both inner coils

Postby Cue Zephyr » Fri Mar 02, 2018 8:47 am

I see. Thanks.

If I have the Tribute L-2000 without the blue wire, can we still use this schematic from your site?

https://www.bassesbyleo.com/paul/k_wiring/l2000k.jpg
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Re: Noise on K-Mod using both inner coils

Postby Ken Baker » Fri Mar 02, 2018 10:07 am

Cue Zephyr wrote:I see. Thanks.

If I have the Tribute L-2000 without the blue wire, can we still use this schematic from your site?

https://www.bassesbyleo.com/paul/k_wiring/l2000k.jpg


You could try it, but I'm not sure how well it would work. Also, it is for single coil on the outer coils, not inners.

K model pickups have, as you've noted, a blue lead. This lead is only connected to the back plate of the pickups and should be grounded at all times. The green lead comes straight off one of the coil connections.

Your bass has 4-lead pickups with no blue lead. There is a small internal, green cross connect lead that goes from one coil to a corner of the back plate. At the opposite corner of the back plate is another green lead that is brought out for connection to the rest of the circuit, and this lead should be grounded for both pickups, which will ground for the pickup and back plate.

Here's an example of that from my L-2500. Understand that the only thing for you to pay attention to here is the coil select and pickup select switches. The volume control and active/passive switch are specific to my bass. Also, this is for single coil on the outers.

Image

This is based upon the circuits developed by member daveplaysbass. You can find his collection of mods here. I have not yet looked into this in depth, so there may be a circuit in there to provide single coil on the inners.

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Re: Noise on K-Mod using both inner coils

Postby Cue Zephyr » Fri Mar 02, 2018 3:14 pm

It looks like I linked the wrong schematic.

My tech used this one:
Image
Last edited by Cue Zephyr on Sat Mar 03, 2018 7:54 am, edited 1 time in total.
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Re: Noise on K-Mod using both inner coils

Postby Ken Baker » Fri Mar 02, 2018 5:25 pm

Cue Zephyr wrote:It looks like I linked the wrong schematic.

My tech used this one:
Image


I've said it before and I'll say it again: Linking images from some other forum does NOT work. You have to log on to the hosting service to view it. If it's visible here, it's because you're still logged onto TalkBass. Do a hard refresh of your browser when not logged in there and the image goes away. Please upload and host images on Imgur and use IMG tags. Kindly do NOT upload this image here as an attachment (see below).

Having said that, I did take a quick look at that image. It's a doctored version of my original L-2000 diagram from many years ago. My name is even there. Kind of pisses me off. It's not like I'm hard to find to ask if it's okay.

This is going to sound corporate as hell, but I have to draw the line some place. Other than member-attached stuff (and I'll be a bit selective here), I'll speak to images and diagrams that BassesByLeo hosts and that we have direct control over. This particular image, even though it carries my name, has been modified and doctored to the point that it is no longer mine. If you want to use the circuit described by the diagram and you're having trouble with it, you'll need to contact the TB member who made the modifications to my original drawing. I'm perfectly willing to stand behind what I do, but not behind what some random TB'er does. Gotta love this free-for-all we call the Internet.

Looks like I'll now be updating the Forum Guidelines.

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Re: Noise on K-Mod using both inner coils

Postby Cue Zephyr » Sat Mar 03, 2018 7:45 am

I'm really sorry - I had no idea that schematic wasn't yours which is why I agreed to using it. We figured it was a clear schematic and went with it. I already was a little confused why the wires were different but there was no series/single/parallel label update. I should have taken note of that.

I've given my tech the schematic you linked and hopefully he can get it fixed.

Is there any chance you could explain to me what's different/wrong with this schematic and what might be causing the noise?
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Re: Noise on K-Mod using both inner coils

Postby Ken Baker » Sat Mar 03, 2018 8:48 am

Cue Zephyr wrote:I'm really sorry - I had no idea that schematic wasn't yours which is why I agreed to using it. We figured it was a clear schematic and went with it. I already was a little confused why the wires were different but there was no series/single/parallel label update. I should have taken note of that.


That diagram, as noted above, started out as mine and is the one you initially linked from a Google Drive. I don't have a problem with that. The reason that I added "Ken Baker and BassesByLeo" to it was because a guy took it to TalkBass and claimed it as his own. Now some other guy grabbed it and edited it extensively enough that I would no longer want my name on it, yet my name is still on it. Am I upset with you? No, you're just trying to get a bass to work and you didn't know any better. Now you do.

I understand that info like this is treated pretty much as grab & go. People want what they want and generally don't give a good crap about how it happens. The idea of proper attribution isn't part of the current Internet consciousness. If someone had taken that drawing and completely redone it, which would probably be an improvement, there would be zero problem. It's an open and publicly available circuit. But to mod one that clearly came from a specific person (ANY person) without even making an attempt to remove the name is unacceptable. To ask that the originator to support the modified drawing is problematic. You didn't know. Now you do. Let's move on.

Is there any chance you could explain to me what's different/wrong with this schematic and what might be causing the noise?


You get one shot at this from me. The way the coil select switch on the TB circuit is set up is the same as I showed you above for my L-2500. Basically, if your tech had closely followed the diagram you'd get single coil on the outers and a quiet bass. Power is as follows: Battery + (positive) goes to the preamp as a hard connection, possibly through a small terminal strip. Battery - (negative) connects to the ring lug on the jack which is then connected to ground, possibly through a small terminal strip. Sleeve on the jack is connected to a ground point in the cavity. Tip on the jack connects to the active/passive switch as shown, possibly through a small terminal strip.

I don't have a circuit for inners that was "built" in-house, which is why I pointed you to the daveplaysbass thread.

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