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Bridge – PU distance

Posted: Mon Jul 02, 2012 4:05 am
by kpettert
Hi Everyone,

I'm about to build my first lapsteel. Its a 8-string with a Jerry Wallace PU.
I think I got most of it figured out but I'm still thinking about the distance between the bridge (i will be using a 12mm diameter brass rod) and the Pickup.
Im looking for a warm jazzy western swing sound.

Ant thoughts or suggestions?

best
Petter
Sweden

Re: Bridge – PU distance

Posted: Mon Jul 02, 2012 12:51 pm
by neatlick
Hi, Where in Sweden have you your bed???
My is in Äppelbo, Dalarna!!!
The distance on my MSA Vintage XL are 2" or 50,8mm, OK
I'm on SKYPE: korksteel1.

Neatlick

Re: Bridge – PU distance

Posted: Tue Jul 03, 2012 2:58 pm
by richard37066
Hey, Petter -

This is a pet subject of mine and I just may have an answer for you. A couple of years ago I asked the same question and some research supported my thinking. I thought that I had stumbled upon something new until I discovered that my friend, Georg Sørtun, had applied the concept to his guitar some years before.

Here's the skinny: - The distance that the pickup is from the bridge determines the ratio of the signal of the fundamental frequency of the string versus the harmonics present on the vibrating string. The amplitude of the harmonics will not change. However, as you move the pickup further AWAY from the bridge (the changer), the greater the amplitude of the fundamental that will be detected. An apparent "mellower" tone. In a sense, it's analogous to the "treble" control on a Hi-Fi set. As you roll off the high frequencies, the overall "tone" becomes mellower. There are those on the SGF, for example, who will swear that the ONLY place for the pickup is 2" from the center of the changer. This is hogwash. The only reason for such a belief is that such a position provides the typical "traditional country" sound, and nothing else. To each his own. We - you and I - prefer something a little different.

I have played passable jazz guitar for over 50 years and I, too, love a mellower tone. I'm in the process of refurbishing an old Dekley. I'm going to expand the pickup cavity away from the changer. Then, I intend putting a pad of Velcro in the cavity, another strip on the bottom of the pickup and then move the pickup - fore and aft - until I get a baseline tone which appeals to me. Then, and only then, will I consider making a permanent installation. If you have the room under the strings for such an experiment then I would suggest doing it. The obvious advantage to this experiment is that you haven't butchered up the guitar while making an uneducated guess as to where it should be placed. In my case, the cavity may then look gawd-awful but I can always fabricate some sort of cover in the interest of attractiveness. Further, if - at some point down the road - I decide that I would prefer a slightly difference sound, I'm not locked into a given position and have to perform major surgery in order to make the change. If you DON'T have room under the strings to accomplish this then I would suggest borrowing a "skinny" pickup - like an old DeArmond - and move it around until you find something which flips your switch. At least you'll then be in the ballpark instead of just playing a guessing game in the dark.

Hope that this sheds some light on the possibility of changing the base-tone of the guitar instead of spending megabucks on electronics which may - or may not - resolve the problem.

Richard

Oh - when I lived outside of Denver, Colorado some years ago and was a fervent Avalanche fan, Peter Forsberg was my absolute hockey hero! A tip of the hat to Swedish hockey players!

Re: Bridge – PU distance

Posted: Wed Jul 04, 2012 2:49 am
by kpettert
Thank you so much richard! I will definitly concider a movable pickup mount!

There is Peter Forsberg, and then there is no one else. :-)

Re: Bridge – PU distance

Posted: Wed Jul 04, 2012 9:04 am
by Bent
If someone can give me ideas to make a moveable pickup, I am all ears. This is to be achieved with adjustment screws or similar, metal moving on metal; not rubber bands and the like. It should be able to move say from starting point which would be pup o/c 2" from the top of the changer finger, towards the finger about 1/2" and from the same starting point(2") 3/4" the other way. Pup must still be height adjustable. It must be an arrangement that requires zero technical knowledge to perform.

Re: Bridge – PU distance

Posted: Thu Jul 05, 2012 7:53 am
by richard37066
Bent -

No guarantees but I'll give it some thought since it might ease the pain in my project. How "readily adjustable" must it be? From the top of the guitar or would you accept having to climb underneath?

Richard

Re: Bridge – PU distance

Posted: Fri Jul 06, 2012 6:27 pm
by Bent
Richard, It has to be so easy that the operator will need no technical knowledge. It should be like adjusting the pup up and down. From the top for sure.
I visualize 1 or 2 screws from the top, of the rack and pinion type. Preferably something commercially available so I wouldn't have to make the actual adjusting mechanism. My visualization, might or might not be what's needed. That's why I am asking for ya'll's ideas ;-)

Re: Bridge – PU distance

Posted: Sat Jul 07, 2012 11:46 am
by richard37066
I'm thinkin' - for whatever that's worth.

Re: Bridge – PU distance

Posted: Sat Jul 07, 2012 4:36 pm
by michaelm
Here's one idea for a movable pickup:

Make a cavity in the guitar body the width of the pickup, the length of the desired travel and deep enough for the pickup and the wires.
Install two parallel rods for the pickup to rest on.
The height of the rods should place the pickup at the desired distance under the strings.
The distance between the rods should be just less than or just greater than the distance between the pickup mounting holes.
Replace the two or four pickup mounting bolts or screws with small J-hooks and nuts that will hold the pickup to the rods.
If small J-hooks are not readily available, they should be easy enough to fabricate from some #4 or #6 all-thread.
To move the pickup, a nut driver or tuning wrench can be used to loosen the nuts, then slide the pickup to the desired position, and retighten the nuts.

This is an untried idea. If this description isn't clear enough, I'll take a crack at drawing up a section view or something similar. HTH.

Re: Bridge – PU distance

Posted: Sun Jul 08, 2012 12:52 pm
by Bent
Michael, your idea does hold water. I need to have time to ponder all things, plus figure out if it is still height adjustable. If you have time, I certainly would like a sketch. If you would do that, send it to this email address: bero1"at"rogers dot com
Thanks!