This is the original article as posted to the VG-8 maillist, with corrections to the measurments.
Folks,
Today is a very good day for me... and for you if you own a Godin LGX-SA.
SUMMARY:
Perfectly usable alternate tunings. No tuner bleed through from
adjacent strings, even at high driver settings of 80 or even 90.
Shrill sounds next to nonexistent. Factory patches sound stellar.
Analog sound directly from piezos improved. HRM sounds never mis-track
(and for those with a GR 30, it now tracks perfectly whereas before it
was almost unusable). Built-in tuner actually usable. Some
distortion sounds which were borderline are now perfectly fine. Acoustic
sounds now have much greater dynamic range, much more like a real acoustic.
Net: VG8,100 percent as intended by the designers. All of these improvements
were made by simply installing a strain relief bridge in parallel with
the piezo bridge. I will be adding a tiff file and photos of the
bridge at my WebSite so that anyone interested can build one for themselves.
I will try to make the WebSite have the address:
http://charliemb.home.mindspring.com/lgxbrig/html/index.htm
and I'll let you know if it's different than that.
DETAIL
I was contemplating selling my beloved LGX-SA and perhaps getting a
Parker with Gk2a, or perhaps hanging a gk2a off my lgx-sa when it occurred
to me... all that's happening is those piezo's are being over driven mechanically.
That is, not electrically. Then my day dream switched to some figures
i saw while reading some of the patents from L.R.Baggs and from Richard
McClish. At first a picture of a piezo with a string angle of roughly
13 degrees to minimize the strain. I remember reading that part of the
problem with obtaining good sound from piezo's is that they are forced
to take the entire vertical load. This vertical force is much larger
than the vibration forces and special amplification techniques had to be
employed in order to extract this low-level vibration signal from this
high-level relatively static signal. "THAT's IT!" I thought,
if I can take the majority of the stress off of the piezo I'll get greatly
improved dynamic range and a cleaner more-true sound. While I looked
around the room for makeshift parts I even theorized that it would solve
the alternate tuning problem. I took a piece of plastic tie wrap
and a thick mono filament fishing line and squished it between the bridge
base -- the black part of the bridge -- and the low E and A strings right
up against the piezo saddle. It sounded great almost completely lacking
in second harmonic. I couldn't resist, I immediately switched over
to an alternate tuning, set it to dropped D (since I only had it installed
on two strings) and long and behold... perfect alternate tuning with no
trace of the original signal at all! (editorial note: for this particular
patch, a Les Fradkin short scale Ric . I'm not ready to make his claim
for all patches just yet, and I know of at least one sound where the high
E had some minute trace, but for example the patch Bendin B was perfect
as well, all bass sounds are perfect etc.)
At this point I had to pinch myself several times. I dropped all the plans I had for this weekend and presumed a new project... to make a precise bridge for all the strings. I thought about just taking my guitar to my local luthier, but I could not contain myself, I couldn't wait till Monday, I had to do it right away. I'm happy to say that I'm writing this on a Sunday night after successfully building the bridge. I was even able to play it for hours earlier today and I even went through all my patches including factory patches and they all sound unbelievable.
HOW I BUILT IT
I actually decided to build it as two bridges, one for the wound strings
and one for the solid steel strings since I figured the heights would be
slightly different due to the diameter of the strings. I thought
about making six bridges, one for each string, but could not help thinking
that the key to this success might be that adjacent strings are coupled
and it may be this coupling that is helping with the alternate tuning.
This would be the case if the VG8 had an algorithm which looked for and
canceled similar vibrations from adjacent strings, which presumably they
do have. I also wanted to be able to change my strings without having
to worry about the bridge coming loose (since I don't want to use any sort
of adhesive or in any other way alter this beautiful guitar). Building
it as a single bridge would not be possible because of the slight scale
length differences between each string and mainly between the wound vs.
un-wound strings. So I had to build it as two bridges.
I built it by making a mold out of paper and Scotch tape, and filling
it with five-minute epoxy. Then filing it down till it was perfect.
If I had the right type of wood I would have built-in out of wood but I
didn't and I've had experience making things with epoxy's in the past so
that's what I had in hand so that's what I used. The bottom line
is to need something with this shape:
(change to a fixed font such as courier to view this)
>
--------+
> ---------
|
> +-------
|
> |
|
> +------------------------+
which follows the radius of the frets and bridge.
For the wound strings the dimensions of the stair steps are
90, 102.5, and 115 mils or thousands of an inch. For the plain
steel strings the dimensions are
85, 100, and 115 mils.
(Editorial note: don't worry if I haven't explained it so well below,
the pictures make it very clear)
Getting back to the way I built it, I have a photo inkjet printer which
is capable of printing on thick card stock. So I drew that shape
out in my image editing program and saved it as a tiff file then printed
it on the card stock. I then cut the printed stair step shape with
a pair of scissors. The card stock being thick enough to have structure
and act as a mold. I printed a total of four and used two per bridge.
These obviously defined two of the side walls, the other two walls I simply
made with Scotch tape. I simply stood the two side walls up on a
strip of Scotch tape with the sticky side up. The two side walls
were put down parallel to each other about 3/16 of an inch apart, hence
that's how wide the bridges end up being. Once the side walls were standing
on their own, I then used more Scotch tape to close off the other two sides
completing the mold. I then used scissors to cut off any of the tape
which extended beyond the dimensions of the card stock. I then mixed
up some epoxy slurped it into a disposable syringe and injected/poured
the epoxy into the mold. It's amazing how true to the mold the epoxy
settles. If you use the tiff file, the correct dimensions are roughly
after all of the printed black is filed down. It took me a while
to file down to that point so you might want to cut out the papers so that
most of the black Ink is not showing. But don't be too greedy it
is better to start too large and have to do some filing than it is to be
shy and have to use spacers. You'll end up having to file the overall
underside and each individual stair step in order to get it perfect.
You want to file just so each saddle is plainly visible when viewed parallel
to the neck, including the deepest part of the notch. Under tension
the strings should not slide within the saddle.
Simply install the bridges behind the piezo saddles, string it up and play away enjoying alternate tunings and all of the other benefits! (By behind I mean between the piezo saddles and where the strings go through the guitar body... let's not make THAT mistake!)
Enjoy, Charlie