McNaught owners...read me

M

mrmojorisin

Member
Messages
1,332
Guys,

I own 5 McNaughts. I love the necks on these thngs...more playable than anything else I've ever owned. And the worksmanship, woods and finishes speak for themselves.

Anyway, 2 of my 5 have P90's in them (a singlecut with a pair, and a Phoenix with triplets). I use Lollar P90's.

I noticed that the Lollars were noisier in the McN's than other guitars I had them in. Being an EE, I started digging in...

Anyway, I found how to fix it and another item which will both quiet down your McN enormously (even with buckers) and also imrprove the tone quite a bit.

First, I noticed that the TOM bridge, NOT the stop bar, was run to ground. Then I measured resistances to ground from each of the saddle tops...huge variations....not a reliable ground. What is going on here is that while the TOM base is grounded, the saddles dont reliably electrically interconnect to the base. Hence the strings don't ground reliably either. This is the source of the noise.

Fixed this by grounding the stop bar. You put a wire inside the hole that the mounting insert goes into, reinstalling the insert over the wire, running the other end of the wire to the back of a pot (this required me to drill a very small hole inside the mounting hole to run the wire into teh control cavity. Took me about 15 minutes to do this.

Bingo. Noise gone.

Second item. I noticed they use .05 microfarad caps on the tone pots. Stealing a trick from Hamer (who really know their electronics) I replaced them with .01 microfarad caps. No more mud when you roll the pots way back...just beautiful singing woman tone. And also because the smaller pot value is bleeding less to ground when the tone pot is off, tone improves as well when the tone pot is full up. This took another 15 minutes.

So, 30 minutes of work and I took a guitar with the body and face of Shania Twain, but like her, a great, but not exceptional voice, and gave her an exceptional voice (Susan Tedeschi!). Its now PERFECT in all respects.

I called the guys at McN and filled them in. I expect them to start doing this as standard fare...

Carl
 
phretbored

phretbored

Member
Messages
4,970
Carl,

Right on.
That's some very useful info.
Thanks for taking the time to investigate the problem and for posting your findings.
I'm sure Dave & Dave are very appreciative.

Any pics of your McNaughty guitars available?
 
ChrisP

ChrisP

Member
Messages
2,950
Originally posted by mrmojorisin
Guys,

I own 5 McNaughts. I love the necks on these thngs...more playable than anything else I've ever owned. And the worksmanship, woods and finishes speak for themselves.

Anyway, 2 of my 5 have P90's in them (a singlecut with a pair, and a Phoenix with triplets). I use Lollar P90's.

I noticed that the Lollars were noisier in the McN's than other guitars I had them in. Being an EE, I started digging in...

Anyway, I found how to fix it and another item which will both quiet down your McN enormously (even with buckers) and also imrprove the tone quite a bit.

First, I noticed that the TOM bridge, NOT the stop bar, was run to ground. Then I measured resistances to ground from each of the saddle tops...huge variations....not a reliable ground. What is going on here is that while the TOM base is grounded, the saddles dont reliably electrically interconnect to the base. Hence the strings don't ground reliably either. This is the source of the noise.

Fixed this by grounding the stop bar. You put a wire inside the hole that the mounting insert goes into, reinstalling the insert over the wire, running the other end of the wire to the back of a pot (this required me to drill a very small hole inside the mounting hole to run the wire into teh control cavity. Took me about 15 minutes to do this.

Bingo. Noise gone.

Second item. I noticed they use .05 microfarad caps on the tone pots. Stealing a trick from Hamer (who really know their electronics) I replaced them with .01 microfarad caps. No more mud when you roll the pots way back...just beautiful singing woman tone. And also because the smaller pot value is bleeding less to ground when the tone pot is off, tone improves as well when the tone pot is full up. This took another 15 minutes.

So, 30 minutes of work and I took a guitar with the body and face of Shania Twain, but like her, a great, but not exceptional voice, and gave her an exceptional voice (Susan Tedeschi!). Its now PERFECT in all respects.

I called the guys at McN and filled them in. I expect them to start doing this as standard fare...

Carl
Click to expand...

Wow :D You are the man!


This thread should be archived...this is great info.
 
M

mrmojorisin

Member
Messages
1,332
A couple of folks have asked me some questions, so I will post here in case other have the same questions...

How do you remove the stop bar mounting insert?

The insert is what the stop bar post screws in to. To remove it you need an old post, or a bolt with the same thread. Screw the old post or the bolt into the insert. Now get a pair of vice grips and lock it on the post/bolt head, with the grips in the same direction as the post/bolt so you can pull it straight out of the body. Hold the body and apply steady even pressure and the insert will slide right out. Some come out easy...some are harder. Just apply steady even pressure and it will pull right out...they aren't glued or anything...they insert is just tapped into the hole.

NOTE - You only need to remove the stop bar insert closest to the control cavity.

Now get a long drill bit in a diameter just big enough for a piece of wire that you'll use to ground the stop bar. Start your hole in the insert hole about 1/4" from the guitar top, in the direction of the control cavity, at about a 30 degree angle (angled toward the guitar back). The hole will emerge into your control cavity.

Now take some wire (I use 18 gauge solid core bell wire, available at Home Depot, etc) and strip one end about 1/2". Thread the other end down into the hole you just drilled. You want to bend the stripped end down into the hole for the post insert so when you put the post back in there is a good connection. Once you have the stripped end of the wire pointing down along the side of the insert hole you can tap the insert back into place. Do this by threading the same post/bolt you used to take it out back into it, and tap the head of the post/bolt gently with a small hammer etc until the insert is flush with the guitar top.

Now all you need to do is ground the other end of the wire to the back of one of your pots.

Where do you get the caps?

I have had very good luck with some .01 microfarad caps I picked up from Radio shack. They are mylar film (not ceramic). They are small, flat, green rectangles with two leads coming out one side of the rectangle. Cant remember who they are made by, but they are "hi end, hi quality" caps...and much better than ceramic caps.


BTW guys, I now have "converted" all five of my McN's. All the guitars are much quieter, especially the P90 guitars, but even the humbuckers are quieter now.

The improvement in tone is quite noticeable in all the guitars too, particularly the humbucker guitars. .05 microfarad is just way too big a tone cap value in anything but a strat. .01 will cut the treble back just fine when you roll it back, yet wont get muddy even when you roll it all the way back. Even more important, with the tone and volume pots full up the hi end tone spectrum will be much better defined and more clear. This was really quite striking to my ears.

Just for the record, the guitars I have done this with have the following pu arrangements:

1) pair Lollar P90 (SC, black limba, rosewood board)

2) triplet Lollar P90 (Phoenix, Mahogany, rosewood board)

3) pair PRS McCarty humbuckers (SC, white limba, rosewood board)

4) pair Lollar Imperial humbuckers (DC, black limba, ebony board)

5) pair of SD Phat Cat P90's (DC, mahogany, ebony board)

I mention this because the tone improvements you hear might depend on the pu's. I can vouch that changing the caps made marked improvements for all the configurations above.

Oh yeah, one last thing. For each of the guitars, before I did the stop bar gounding I checked to see how effective the stock TOM grounding was. I didn't have a good connection between the strings and ground on any of the five.

Lesson learned:

Always ground the stop bar, not the TOM bridge.

Carl
 
phretbored

phretbored

Member
Messages
4,970
illinimax

illinimax

Platinum Supporting Member
Messages
1,594
Thanks for sharing this (think you're a gEEk? - I've got a physics degree, hehe). I've got a few tweaks that worked to quiet my McNaught as well, basically eliminating some ground loops. I'll post a picture when I get back home later this week. Pretty simple stuff.

I can't wait to try this mod. I have a Gibson ES135 that's too damn noisy, and I wonder if it suffers from the same issue.
 
illinimax

illinimax

Platinum Supporting Member
Messages
1,594
Question for ya. Given that the stoptail now serves as a superior ground, do you disconnect the other faulty ground going to the bridge?

Thanks again for sharing your findings.
 
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