Redesigned PSG

ed packard · From: Show Low AZ

Some time ago, I did a series of posts re Properties of Materials that could be used re steel guitar construction; That was to think my way through which to use on the anticipated redesign. I am sitting behind the redesigned unit as I type.

The instrument that was modified is a 14 string, 9 pedal, 7 lever, with lok Sierra Session Series hardware.

The modifications are:

1.The Tuner has been integrated with the Changer (one unit). It is still on the players right.

2.The strings are 11/32" apart at BOTH ends of the neck. I did not know that I would likw this so much! Pull offs, Hammer ons, finger pulls, are all cleaner to make. Bar/string noise is down because the bar can be used on only the strings that you want. Rips and arpeggiated chords are more defined.

3. The NUT has NO rollers.

4. The angle of the strings to the NUT and the CHANGER fingers is <2.5 degrees!!! A real worst case re rattle etc. This minimizes the pressure (hence the friction) against the finger and the nut, thus minimizing material deformation for both strings and what they press against.

5. The "unplayed" string length for the G# at the changer/tuner end is 1.1"; This is the longest "unplayed" string length. This is from ball to the top of the finger. The length from the ball through the winding is 3/4". The "stretch" to get to pitch for the G# is about 0.280" for two octaves. The amount of stretch for one halftone (G# to G) is 0.027", or about one turn of a 4X40 screw.

The unplayed string length at the NUT end was set at 1/2". My "played" string length is 25". My "stretched" string length is therefor 26.6". The string motion at the nut
would be 1/26th of 0.027", or about 0.001", and at nearly zero friction; I see no need for a roller! The nut end unplayed string length can easily be reduced to <1/4", reducing the motion to <500 microinches!

6. There is no need for pull tools to replace strings. The same string can be removed and replaced if desired.

7. The string planarity can be adjusted to suit if the Strat type string saddles are used for the nut. These need to be reduced a bit in width to make them fit. You could play with variations in string length for intonation (if that is your choice)if these were on the bridge end.

In an earlier post, I described nut rollers with an offset axle to allow adjustment of the string planarity; I decided against that for this redesign in favor of simplicity.

8. The fretboard is now an etched glass drop on/in. Later I will mill/route out the neck to allow using backlighting, circuitry, and such, ..quarter tone scales anyone?

To do the above mechanical mods, I set up a minimal machine shop (poor man's edition).

To check for any possible sound changes that might have occurred I obtained a Spectrum analyzer, a storage oscilloscope, and other electronic stuff, ..so we can now put numbers on "tone", "sustain", so that they can be objectively compared.

Now to get the Changer/Tuner and the Nut placed on opposite ends. When that is done, the Strat saddles can be changed out for the ones with Piezo pickups in them. I won't do that, ..I will let a builder do it.

[This message was edited by ed packard on 05 August 2004 at 06:21 AM.]

Ray Minich · From: Bradford, Pa. Frozen Tundra

C Dixon · From: Duluth, GA USA

Good luck dear friend,

carl

Fred Justice · From: Mesa, Arizona

Hi Ed,
I remember talking to you about this when I was at the Casino in June,sounds like your getting there buddy,when will we see photo's of your labor?
BTW,i'll be in Flagstaff the 5th 6th &7th at the Zoo Club with the same band,come on over.

------------------
Fred Justice
Events Dir.
SWSGA www.swsteelguitar.com

David L. Donald · From: Koh Samui Island, Thailand

This data, and a finished [prototype will very interesting to see.
Ed keep up the great research.

Pete Burak · From: Portland, OR USA

Hi Ed,
Are you bringing this axe to the Arizona show in Jan?
'Might see you there.
Pete B.

Jackie Anderson · From: Scarborough, ME

Ed, in what file formats will your sound lab accept data...?

ebb · From: nj

just talked paul redmond (whitney) who thought your post was dead on target.

ed packard · From: Show Low AZ

Ray M: Data will be mostly "on request" by direct e-mail, as will photos. The problem with "data" is that understanding what it means usually means learning a new language/jargon.

CD: Thanks. "Luck" sir??? How about serendipity? I believe more in experiment, analysis, and diligence than in luck, ..if you prepare good "luck" will happen.

Fred: Justice is alive and well in AZ! Photos on demand via direct e-mail.

DLD: This is the "proof of concept" model. It is applied in such a way that the instrument can be returned to it's orig' form. As above, Data and Photos if requested as the project progresses.

PB: Probably have one at the AZ show.

JA: I do most of my comp' stuff in Excel or 123. Have Mathcad, and access to Ansys, and Vector Fields software for the BIG issues.

EBB: Gotta do something twixt the cradle and the grave; Glad that PR likes it.

All: The "data" to be derived will be "comparitive"; Modified vs non modified, ..Session vs Show Bud Pro, ..Session vs Elegante, ..as these are the instruments that I have. I have access to an old MSA also so may throw that into the mix.

The "sustain" units will be either db loss per unit of time, or % loss per unit of time, ..I lean toward % signal decay per second as db would be less understood than %. Charts/Graphs will probably be the medium.

The "tone" units will be some form of frequency magnitude vs time. The effect of volume pedal loading on the spectrum will be considered. Again, Charts/Graphs.

Null(dead)spots on the neck, differences in pickup response, the effect of string tension on output spectrum can also be evaluated with the available equipment, as can string stretch vs tension.

Pitch change vs body stress, pedal/lever activation, temperature, etc. can be resolved to tenths of cycles or better.

This may be a bit extreme for PSG, but I don't have hard disk drive design issues to fret about any more (tired and retired).

If you are interested in this kind of "stuff" (think George Carlin's routine) let me know and I will add you to the e-mail list.

edp

David L. Donald · From: Koh Samui Island, Thailand

Ed send me what you got.
I am at home with Jargon... lived with her for years.

Too bad you won't have it at ISGC.
I would love to see it side by side with Carl Dixon's pet projects and the two of you in deep discusion.

ed packard · From: Show Low AZ

The first data set is about to be sent (this PM on the west coast)to those that have asked for it. It will be sent in 4 parts as photos and charts take up a lot of space.

Part1 covers the modifications to the instrument, mand the philosophy behind them.

Parts 2, 3, 4 cover the results of the basic sound performance measurements taken at frets 12, 24, and 36 using a spectrum analyzer.

Scott Swartz · From: St. Louis, MO

Ed,

I would be interested in your data and pics.

I sent an email with the correct address to send to.

Thanks,

Scott Swartz

C Dixon · From: Duluth, GA USA

ed packard · From: Show Low AZ

The first four parts covering including the photos of the "redesigned PSG" and the data/charts showing the effect of picking location upon harmonic content(the "tone" thing)were e-mailed yesterday. Sorry about the sizes of the files, that is the nature of the "data" business.

If you did not get yours, then you are not on the list, ..if I missed you please let me know.

The next "data" send will cover harmonic content as a function of how hard the string is picked. Then we start on the "sustain" issue.

Ray Minich · From: Bradford, Pa. Frozen Tundra

bob grossman · From: Visalia CA USA

Years ago, Tom Bradshaw and I were discussing what else we could add to a PSG, what with dual levers at three knees, two up levers, a wrist lever (MSA)and so on.

How about a chair that swivels and tilts backwards? Connect a cable to each side and the front for three additional pulls. Right, left, and rear backwards.

No?

[This message was edited by bob grossman on 11 August 2004 at 01:19 PM.]

ed packard · From: Show Low AZ

Glad that you picked up on that Ray, "data" was in quotes just for you. The "data" is actually in picture form where the reader can derive their own numbers and form their own relationships from the charts, hence the hi resolution and large files.

The charts are screen captures (using Hijack) of Spectrum Analyzer and O'scilloscope presentations of PSG signals. The SA and O are a software that can be downloaded for free in it's basic form, and upgraded to what I am using for <$100.00. It uses your computer's sound card as the input/output for the signals. The result can be a numerical and repeatable discription (and visualization) of instrument signals, which in turn will allowe "objective" comparisons of instruments and design changes re their sounds.

BG: It is a good thing that chaps like you and TB sat around joking about what to add and how to add it or we would still have horse and buggy transportation and non electric lap guitars. Once upon a time one of my relatives bought a Ford auto. After an extended trip and lots of problems he went back to the plant and complained about how things were done and how they could be made better. They did not want to hear it and told him "if you are so damn smart, why don/t you go build your own?". He did, you figure out which Auto it was.

I redid the Tuner pieces in the experiment to eliminate the string slot and installed them yesterday, ..looks better, measures (sounds) the same as before.

I have taken the "data" for the "soft picking" harmonic content comparison, and for the content two seconds after picking (first cut at defining "sustain". I will put words to the music and send these by next weekend.

Just think, if I did not do this thread CD would have one less place to "spread the word".

Ray Minich · From: Bradford, Pa. Frozen Tundra

Ed. I wonder what one would see if they attached strain gages in the classic rosette pattern to the body in several places and looked at the 3D behavior of the body as the note sustains. Digitize about 9-12 axes at 100 kHz each.

Jimmy Stewart and "The Flight of the Raindeer" comes to mind

(oh, the good old days of data acquisition...)

Nice job Ed, I'm enjoying your project!

[This message was edited by Ray Minich on 12 August 2004 at 04:36 PM.]

ed packard · From: Show Low AZ

RAY; One way to see the body/string connection is to excite the body (calibrated hit in several places) and do a spectrum analyzer look at the output of the pickup. The strings sympathetic to the body/leg/axle vibrations will be the most excited. We will do some of this on the various instruments available as part of this excercise.

ed packard · From: Show Low AZ

Just e-mailed part 5 showing the spectral response (think available tone)of the three tap positions of the pickup on the modified Sierra Session With no load, and the result of volume pedal loading (500 K Ohms)and no amp attached. This is for those that might not be on the list but be interested in this aspect.

Ray Minich · From: Bradford, Pa. Frozen Tundra

Ed, I always liked Bruel & Kjaer's "calibrated hammer"...

ed packard · From: Show Low AZ

Some folk have said that the text came thru but the images did not. The documents were sent as a WORD file. I have just sent, to those on the list, a WORD file with an assortment of image formats. Please let me know which ones do and do not open for you.

Anyone else interested in this test send?..or have an input?

This is probably the wrong place for this subject but it is tied to the thread.

ed packard · From: Show Low AZ

Replacements for the last two parts done. Tightened up the loop to reduce extraneous noise.

Thanx to those that replied re PHOTO receipt problems. The format will be in WORD with GIF or JPG photo inserts as these seem to work the best.

5 PARTS will be sent tonight or tomorrow, ..the two are replacents for the tapped pickup spectral response, and the sustain spectral response at 0,2,5,10, and 20 secs.

The new parts are string noise for various and grouped strings, body to free strings coupling effect, and body to constrained strings coupling effect.

All 5 of these parts were taken re the same calibration setup. Interexsting things to be seen in these charts.

ed packard · From: Show Low AZ

All 10 Parts to this series have been edited into one and sent to those that requested to be on the send list. A number of interesting things showed up from the testing. If any one else wants the edited into one paper, please let me know. The principles and methods shown therein will be used when (next week?) we start comparing to the Show Bud Professional instrument.

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