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Topic: psg with adjustable bridge? |
Ben Godard
From: Jamesville NC
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Posted 16 Feb 2013 10:45 pm
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I was reading an older post discusing the pros and cons of ET vs JI tuning methods and Paul Franklin came up with an interesting conclusion a while back. He said that the next step in steel guitar evolution was to have an adjustable bridge like most other guitars have.
My question, is Has anyone tried to build one of these yet. |
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Roger Shackelton
From: MINNESOTA (deceased)
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Posted 17 Feb 2013 12:55 am
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I believe I saw a One-Off S-12 PSG in St.Louis some years ago, made by the son of the owner of Howard Steel Guitars. Each bridge lever was ajustable back and forth.
Roger |
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Jim Pitman
From: Waterbury Ctr. VT 05677 USA
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Posted 17 Feb 2013 2:53 am
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Lamar makes a PSG with a straight pull changer that I imagine makes it possible to adjust each string's intonation individually. However, that's supposition on my part. Someone else more familiar may chime in and counter that. |
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Georg Sørtun
From: Mandal, Agder, Norway
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Posted 17 Feb 2013 3:48 am
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Tested out adjustable - intonation - bridges at both ends during the final modifying process of my Dekley S10 back in the early -90s.
What I found out was that that PSG lost some of the sonic character that makes a PSG stand out, if length of individual strings were adjusted too fine for perfect intonation - it started to sound a bit too much like a regular guitar. This has - to my ear - to do with the characteristic "clashes" between base frequencies and harmonics on "high-tuned straight-bridge PSGs", a sonic character I very much wanted to keep despite the fact that the tone of each string isn't "pure".
Found the best-working compromise was to angle the regular straight-bridge/changer slightly to make high (thin/plain) strings intonate reasonably well with low (thick/wound) strings. String 10 is about 3 millimeter longer than string 1 on that PSG now, which keeps the bridge-angle well within what that PSG can handle without causing mechanical problems with the changer.
That PSG is by far the easiest to tune up and play in tune of all my PSGs, and some of that can be contributed to the bridge-angle that balances the strings better than before I modified it.
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IMO, to make an adjustable bridge work on a PSG without damaging its sonic character, both the bridge and nut should be adjustable and optimized for tone and intonation - and nothing else. As I see it, that is only possible if the changer is moved beyond the nut - changer integrated in the keyhead, so "tone" won't depend so much on mechanical compromises as it is on all regular "bridge = changer" PSGs.
So, that is what I am working on for my own PSG design - complicated and delayed by the fact that I want a PSG with regular-looking keyhead despite the fact that all tuning keys must move individually to introduce changes. Fun project |
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Ben Godard
From: Jamesville NC
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Posted 17 Feb 2013 7:59 am
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Wow George
Sounds like you have been down this road for quite some time. And tackling such a project is one hell of a task. I wouldn't know where to even start. It always seems like the more parts there are, the more possibility of it being less mechanical stable and subject to detune due to flexing or thermal growth.
But by god if you were to accomplish this design without losing much of the quality (namely tone, sustain, string separation,playability, and resistant to detuning) You would be completing the next step in psg evolution and I believe it would make its mark on all of the players out there.
My personal advice which you probrably already know. Stay away from aluminum on as many parts as you can. Aluminum may be light but it expands and contracts too much with temperature change in my opinion. Also dont make the mechanical advantage of the changer mechanism too sensative. Yes a tight guitar with short throws can be nice but if it is really easy to push a pedal down a short ways and change the note, then it will that amount easy to detune as well if any of the aluminum parts expand or retract in temperature.
My emmons push pull stays in tune the best of any guitar I've ever had. Its all steel roddding. Of course a push-pull is a totally different design and that may play a big part of its stability.
My Franklin D10 which is obviously a nice guitar, is real tight and quick too play. And I love the clean tone. Nice guitar but all the rodding is aluminum plus the changer has an angle that produces more mechanical leverage than the average psg. Due to both of these factors contributing together makes a very sensative changer which is prone to detuning with temperature change.
That being said, if you are playing in a climate controlled studio, then all the above isn't that important. |
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Jim Pitman
From: Waterbury Ctr. VT 05677 USA
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Posted 17 Feb 2013 8:21 am
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Yes Ben, I too favor steel rodding over aluminum. The coefficient of expansion is quite high for alluminium.
It's rather unfortunate that our most popular pedals are the farthest away from the changer. Since most all pull guitars have a length of rod between the changer and the pedal stop, they are quite affected by temperature change as the rod grows and shrinks. There's one "all pull" exception. The Kline PSG has its' stops at the end plate near the changer. That guitar is quite stable with temperature change as a result. The price paid for this is some extra complexity as a pulling yolk is required though. |
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Jim Palenscar
From: Oceanside, Calif, USA
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Posted 17 Feb 2013 8:25 am
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"the changer has an angle that produces more mechanical leverage than the average psg"- would you care to expand on that comment Ben? In looking at the Franklin changer in the past it seemed to me that the pivot points were very similar to the older MSA changer. |
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Dickie Whitley
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Posted 17 Feb 2013 9:24 am
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OK, now you're got my curiosity up because the pivot point of the Franklin steel guitar is a "selling" point that is mentioned on the site. So did MSA have a similiar changer and go away from it? If so, just curious why. I know there is a price/weight difference, but I've always wondered why the changer and other parts are aluminum instead of steel, seems to me we're shooting ourselves in the foot using a metal with a relatively high expansion/contraction issue temperature-wise. My info is that aluminum is nearly twice as bad than steel in that regard.
Again, I understand the price/weight issue, but if performance is what we really want then we appear to be headed in the wrong direction from my point of view.
Thoughts? |
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Richard Sinkler
From: aka: Rusty Strings -- Missoula, Montana
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Posted 17 Feb 2013 10:04 am
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Oh boy. I just see all the posts from people who screw up the adjustments complaining they can't get their guitar in tune. _________________ Carter D10 8p/8k, Dekley S10 3p/4k C6 setup,Regal RD40 Dobro, Recording King Professional Dobro, NV400, NV112,Ibanez Gio guitar, Epiphone SG Special (open D slide guitar) . Playing for 54 years and still counting. |
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Georg Sørtun
From: Mandal, Agder, Norway
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Posted 17 Feb 2013 10:14 am
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Ben, you mention many of the potential problems I have been wrestling with for years.
Changer will be a "knife-edge" variant All-Pull, with 3 positions in the knife-edge coupling to "gear" it right for strings that need long travel, medium travel or short travel for full-note changes. That will pretty much take care of sensitivity issues at that end. Obviously the changer will be made mainly of steel, with hardened steel in the knife-edge couplings to assure accuracy and long life.
Simplifying and minimizing the number of parts is one of my goals. Close to linear pull on strings is another. Time and money spent in designing and building it isn't much of an issue ... I aim at getting it just right.
Once up and running those who like (some of) it will be able to copy whatever, as I will only develop and build two versions - one fully mechanical and one servo controlled - of the same base-model.
As for aluminum and temperature...
you may not believe it but the old modified Dekley with its 20 millimeter thick laminated aluminum neck, has gone from being in freezing temperatures in a car for hours, into room temperature, and been immediately ready to play without retuning - and it remained stable. That is not because its aluminum neck doesn't expand and contract - it does, but that the neck is mounted so it expands and contracts "in sync" with the strings and the aluminum frame holding the mechanics. Back half of the neck expands into a rubber-filled void between it and the nut, and the fact that the neck is solid and laminated of two 10 mm thick "plates" and raised - floating in the air above the sound-board, means it only expands/contracts a tiny bit in length with the strings - just enough to follow the rest and keep tuning pretty stable more or less regardless of temperature swing.
I am no expert on metal alloys, but I do know what to ask the real experts for. For the aluminum neck for my Dekley S10 I explained the problems and asked for the most stable and resistant aluminum alloy they could get hold of. They ordered some made for toughest conditions and smallest tolerances on oil platforms in the North Sea - don't ask me what that aluminum alloy is called/numbered or exactly what it is used for - and told me it was the best they could find on the market that might minimize my problems. One thing they said though, was: "you can't polish it to a true shine no matter the method", which was fine with me since I'm not particularly fond of shiny things
No question about it: my regular and unmodified Dekley D10 with its wood neck, fluctuates a lot more with temperature than my modified Dekley S10 with its solid aluminum neck. Also much stronger body-vibrations, purer tone and better string separation in the modified Dekley S10 with its "center-mounted floating neck".
I will use a similar "center-mounted floating neck" construction for my own design, and just hope I can get hold of the right aluminum alloy once more. Since my design won't have a sound-board or regular body, I am also designing in an adjustable "backbone" for the neck to increase and fine-tune its stability and sonic properties. Think of the neck as a "T" profile put together of different materials to get the right properties.
No wood anywhere in my design, so those who like nice lacquered surfaces will be disappointed. It will have individual-string adjustable bridges at both ends though |
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Gary Patterson
From: Gallatin, TN
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Posted 17 Feb 2013 10:32 am
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Well, I know some will find this controversial, but I can show that compensation (if it's needed at all) is just as effective by changing length at the NUT END as the bridge end. This defies intuition, but it really does work. Geoff Stelling demonstrated this decades ago with his compensated nut design for banjos. More recently, Buzz Fieten has promoted this concept on 6-string guitars.
The reason it works is that the process of varying the string length requires an offsetting change in string tension to tune the open string. The reason compensation is needed at all is to offset the increase in string tension when the string is pressed to the fret.
For a PSG, I would think it would be far easier to implement an adjustable length roller nut than to add such a feature to an already complex changer (bridge).
Let the flaming begin. |
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Dickie Whitley
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Posted 17 Feb 2013 10:33 am
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Well, Richard, we have had endless banters on tuning with different people insisting their's was the only way and everybody else was wrong (despite the fact the "big dogs" use JI in some form and they're the ones making the big money, go figure). My question is why we're using aluminum on steel strings? Is it written somewhere "Thou Shalt Not Use Steel Changers"? |
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Bob Littleton
From: Camas, WA
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Posted 17 Feb 2013 10:55 am
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Easy fix! Play in tune! |
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Richard Sinkler
From: aka: Rusty Strings -- Missoula, Montana
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Posted 17 Feb 2013 11:05 am
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Actually, if someone misadjusts the bridge to where the intonation is off , there really is no way to play in tune consistently all the way up the neck. Had a regular 6 string guitar that was this way until I had someone adjust the bridge saddles and get the intonation set right.
Dickie, I hear ya. I would rather have stainless or some sort of plated steel for my changer fingers. My first guitar were ZB's, and they had steel fingers (actually they were steel caps that were removable if need be, although I never had issues with them getting grooves in them from the strings like aluminum fingers do). _________________ Carter D10 8p/8k, Dekley S10 3p/4k C6 setup,Regal RD40 Dobro, Recording King Professional Dobro, NV400, NV112,Ibanez Gio guitar, Epiphone SG Special (open D slide guitar) . Playing for 54 years and still counting. |
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Georg Sørtun
From: Mandal, Agder, Norway
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Posted 17 Feb 2013 11:10 am
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Gary Patterson wrote: |
Well, I know some will find this controversial, but I can show that compensation (if it's needed at all) is just as effective by changing length at the NUT END as the bridge end. |
Not quite, but close. Improved intonation for open strings - with and without pedals - at the nut, do follow the bar up the neck, IF the bar is played at a slight (barely visible) angle. Since we all (I hope) place the bar and play by ear, that slight angle isn't a problem.
Best result is achieved by having individual-string adjustable bridges at both ends though, as the angle with which strings enter the bridges from beyond the bridge-points are not the same at both ends - especially with regular keyheads, and these "entering-angles" skew the exact points at which each string start vibrating over the two bridges. Add the skew and intonation behavior for wound vs unwound strings, and the (although slight) advantage in having lengthwise fine-tuning at both bridges should become even clearer. |
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Dickie Whitley
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Posted 17 Feb 2013 11:25 am
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I would ask the following question: Are the changes you are suggesting going to be looked upon as cost justifiable?
Sounds like a lot of "tooling" to make this work, and with all the possible adjustments that may have to be done, are we complicating this beyond reason?
At this writing, I'm not convinced the cost or complication is worth the effort. With that said, I certainly don't want to disuade anyone from trying to improve our instrument. I just don't believe in complicating it more than it already is. Then again, I'm the one advocating for steel changers. |
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Richard Sinkler
From: aka: Rusty Strings -- Missoula, Montana
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Posted 17 Feb 2013 11:44 am
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If I remember right, the ZB's I owned had an adjustable nut assembly, I believe for the purpose of adjusting intonation. Notice the slots in the nut assembly where the screws hold it down.
_________________ Carter D10 8p/8k, Dekley S10 3p/4k C6 setup,Regal RD40 Dobro, Recording King Professional Dobro, NV400, NV112,Ibanez Gio guitar, Epiphone SG Special (open D slide guitar) . Playing for 54 years and still counting. |
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Georg Sørtun
From: Mandal, Agder, Norway
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Posted 17 Feb 2013 12:06 pm
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Dickie Whitley wrote: |
I would ask the following question: Are the changes you are suggesting going to be looked upon as cost justifiable? |
For regular PSG designs, no ... well, maybe adjustable nut can be on most PSGs, if enough players want them.
I design mine to be a very cost effective construction, despite the fact that I won't produce it in series for sale. Design/development is costly though - especially in Norway, but who cares ... retired engineers also need hobbies |
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Dickie Whitley
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Posted 17 Feb 2013 12:08 pm
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Georg, I understand, my retirement is in the cards in about 5 years (I hope). I think my other hobby will help though (ham radio). |
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Shorty Rogers
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Posted 18 Feb 2013 9:46 am
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Richard, Did you ever consider switching the steel caps on the ZB changer to aluminum. Greg Lasser did this mod on a few ZBs: his, mine and Pete Grant's to name three. Idea was to soften the ZB shrill. I really preferred that softer sound. |
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Richard Sinkler
From: aka: Rusty Strings -- Missoula, Montana
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Posted 18 Feb 2013 9:50 am
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Shorty, no I never did. I knew Greg made them, but I never felt the need. I was also thinking of having him make some of his ball bearing rollers for me, but never could afford them at the time. _________________ Carter D10 8p/8k, Dekley S10 3p/4k C6 setup,Regal RD40 Dobro, Recording King Professional Dobro, NV400, NV112,Ibanez Gio guitar, Epiphone SG Special (open D slide guitar) . Playing for 54 years and still counting. |
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