Graph-Tech Ghost Info

Started by Elantric, March 10, 2008, 11:15:34 AM

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Elantric

#50
In my experience, I was attempting to play Jeff Beck style Harmonics, on the "G" string, but it was impossible because the sound would completely cut out when using the whammy bar to lower the pitch more than 3 whole steps.  Various other strings would "drop out" along the way too, by simply pushing the whammy bar down.
Its simple physics -

No string pressure on the piezo Saddle = no sound.

and FWIW - lowest cost GK-KIT-GT3 is Andertons UK $135 with shipping

clamhands

#51
Quote from:  cynegetic on February 05, 2010, 10:59:49 AM
Did you get to try the dive bomb thing? I too am curious about that.

Ok...tried the dive bomb thing.  I think the question I'm being asked is "does the piezo output remain solidly consistent up to the point where the a string hops out of the saddle or does the sound start to cut out when the string is still in the saddle (where the string tension is "really floppy")?  The answer is that the piezo output starts to cut out when the string is still in the saddle.  With my current set up, there's only a fraction or two of an inch travel between the point where the sound cuts off and the point where the string hops out of the saddle.  I have to be moving the bar very slowly and purposefully to find this point, but I *can* do it and I see this being a problem if I used the trem more aggressively than I do.

Here's what I just tried (repeating about 10X):

* Turned on the VG-99's tuner in single string mode and made sure I was in tune.
* Hit an open low e and dove the trem until the strings just started to buzz against the frets...The tuner consistently thought this pitch was an A.
* Hit the open low e again and very slowly dove until the string "hopped" out of the saddle...The tuner flickered a lot here and appeared more to be "guessing" the pitch but it consistently displayed a C or C# right about the point where the sound started to cut in and out.  Again- there's a ton of objectionable string buzz going on at this point and with my set up it takes only a slight movement at this point before the string totally hops out of the saddle.

Did I answer the right question?

cynegetic

That's what it does on the ibby double edge too. I thought maybe the would have designed that out of it. Maybe by having the piezo contact angled back and closer to the pinch point of the lock so it retains contact longer. Kind of defeats the purpose of having a floyd if you can't go crazy on it . Oh well ;(

aliensporebomb

This only effects the Ghost and not the GK3 users I take it?
My music projects online at http://www.aliensporebomb.com/

GK Devices:  Roland VG-99, Boss GP-10, Boss SY-1000.

vanceg

Quote from:  aliensporebomb on February 06, 2010, 09:19:18 PM
This only effects the Ghost and not the GK3 users I take it?

Well, sure: The GK-3 doesn't care what the pressure of the strings on the saddles is.  I have had times when I've dive-bombed so far on my guitar that has a floyd and GK-3 that the strings stick to the GK-3...but they are pretty much completely slack by that point anyway (WAAAAAAY more than a third down, more like an octave and a half). 

Generally, NO, this "sound cuts out when I do 'dive bomb' whammy bar work" issue does not present itself when using a GK-3 (or 2).

Vance

Meltdown

The GK3(2) route is still the way to go when using a whammy imho
Visit my website!
http://www.tachyonmusic.com

clamhands

#56
In my case the only string that I've been able to get to cut out on my Graphtech bridge had been the low E.  The E cuts out after bending over an octave downward and seems to be because the string physically falls out of the saddle.  Again, the string is usually so floppy and has made enough contact with the frets at this point that there's very little musically useful happening anymore. All of the other strings in my bridge stay in their saddles and produce consistent output all the way through the downward bend range.  And again,  it requires a movement of only a millimeter or two between the point where the sound cuts out and the point where the string slips out of the bridge.


Elantric

#57
Thanks for the report.

I have a Variax 600 that i swapped the stock L.R. Baggs Saddles for Ghost Graphtech, and now "finally" I can push the whammy bar down a considerable distance before the piezo sound cuts out.

But this also negatively impacted the DSP Alt Tuning - now warbles a lot more due to adjacent string mechanical crosstalk from the Graph-Tech Piezo Saddles

The Graphtech Strat Saddles have the most sensitivity to poor downward string pressure under these conditions.


But i have zero experience with the Ghost Floyd Bridge.

 

clamhands

#58
FWIW...I was watching an interview with Jerry Cantrell's guitar tech last night (Dunlop TV on You Tube).  During the interview the tech was showing off several prototypes of Jerry's new signature G&L model and noted how they had to go through several revisions and ultimately recess the Kahler trem bridge they are using to try to prevent the strings coming out of the saddles during dives with that bridge design as well.

michaiel

I installed Graphtech Ghost saddles in one of my instruments and have feedback problems now. I have set the noise suppressor in the vg 99 at the instrument input and cranked up the threshold, but if I play a chord and mute it with my palm i still get noticeable feedback even with headphones on. I have tried setting the gk input sensitivity down considerably and it is on the G setting.
This is only on high gain amp models. I have also turned all the gain setting down, but it is still present unless the amp is low gain ( tweed, roland, etc..)
I do not have this problem on my gk2 equipped guitar.
Let me know if you have any questions.
thanks

michaiel



michaiel

feedback squeal...i contacted Graphtech and this is the reply I got from them....

Okay, this I have heard of. But I don't know the solution. Apparently some of the high gain amp  models on the VG-99 are prone to this. This is the first I've heard of a side-by-side where the Hexpander exhibited the problem, but a guitar with a GK3 does not.

I know that Roland made some changes to the way the 13-pin jack operates when they came out with the VG-99, and it's possible that some of these changes alter the way it interfaces with the Hexpander.

We're keeping an eye on this, but at the moment we unfortunately don't have a definitive solution. Check the MIDI guitar forums for some discussion about this.


Morgan Ahoff
Ghost Technical Support
www.graphtech.com
Tel: 604.940.5353 ext 26
Fax: 604.940.4961

admin

#63
What type Piezo Bridge do you have?

Fender or Gibson?

If Gibson style, try this

Crank up the volume, and when you have feedback - see if the Feedback stops when you apply downward pressure on the bridge - right above the height adjust posts.

If the feedback stops when you do this,
The solution for Gibson style tune-o-matic piezo feedback problems is:


1) adjust bridge to the Height you like.

2) remove strings 

3) Go to hardware store and buy a 3/8" wooden dowel.  Cut it and sand it to an exact length,  so it can be fitted directly under the middle of the Bridge - to act as a center support "block" for the Bridge - to prevent the bridge from micro pivotal "rocking" on the height adjust posts.
which is one source of  the howling feedback.

4 ) restring guitar   

read below:
RMC says:
"Note that tune-o-matic bridges are notorious for resonating at a
high-frequency in a front-to-back pendulum mode. This results in a
distinctive ringing which can be heard by tapping the front face of the
bridge with a metallic object even if the string segments are damped,
and wont disappear unless the middle of the bridge is blocked
mechanically with a suitable damping support (like a hardwood block)."



So adjust your bridge height action where you like it using the thumb screws under the bridge, then carefully construct a hardwood block which will be fitted under the the center of the bridge, and make contact with the top of the guitar. If constructed correctly it should be hidden directly under the bridge. 

i know Carvin uses Graphtech Ghost Tune-o-matic piezo bridge and electronics -  - but the identical physics apply. 


Read this whole thread too
https://www.vguitarforums.com/smf/index.php/topic,653.0.html


michaiel

Basically they are strat saddles, here is the part #.....
Graphtech
ghost Saddle Pickups PRS Trem
Product #: PN-8220-00

HAMERMAN409

This is a bit of a stab in the dark but I seem to recall a somewhat similar problem happening to some of the people who did Variax "conversions"; it may even have ocurred on some stock Variaxes. The guitars would generally work and behave normally but would be prone to unwanted feedback on high gain patches. In these cases the solution was better shielding of the piezo signals and/or the guitar in general. The thing that throws you off the track is that it manifests itself just like normal (acoustics based) guitar feedback.

No idea if this will be of any help but I figured it couldn't hurt to throw it out there. Please let us know if this does or does not help so that we can build up our knowledge base on the subject.

michaiel

The body cavity is shielded. I am not sure what to do yet....

paults

Here are a couple of thoughts:

If the saddles are PRS size, are there spaces between them when mounted, or do they all touch, like saddles usually do? 

If there are spaces, there may be resonant feedback because of both sides of the saddles are free standing, and able to vibrate independently of the frequencies in the other saddles. 

Since they need the string pressure to function normally, you may be able to slacken sets of five strings to find one or more specific offenders.

If there are specific problem saddles, you may ne able to demonstrate the need for replacement.

If its all of them - is your piezo calibrated to respond similarly to the GK guitar?  Are you using two separate modes for the two pickups?
If the piezo sensitivity is set quite a bit higher than the GK, that could be a likely reason. 

 

michaiel

I will look into this tonight and follow up. I have 4 instruments with this setup and it will give me a good idea what works.
thanks

michaiel

I have not found isolating any of the piezos to help. It is beginning to look like I made a 1200.00 mistake with their products.

I just got the reply from Graphtech....
No, there is no difference whether ghost saddles are touching or not. We just got results from an independent tester at a university, and he reported that the crosstalk between our saddles was so small, he couldn't measure it. It fell below the noise floor.


Morgan Ahoff
Ghost Technical Support
www.graphtech.com
Tel: 604.940.5353 ext 26
Fax: 604.940.4961

clamhands

I have a Ghost equipped guitar and a RR strat as well.  If you can provide a VG-99 factory patch where this is happening or attach an example), I'll see if I can replicate as well.  I've conversed with Morgan Ahoff in the past as well and will add a "me too" with him if I can replicate the problem.

One thing to check for...When playing some of the STUDIO METAL mag pickup only patches I downloaded from the patch section of this site I discovered that with *my* Ghost system if I leave the output toggle in mag only or mag/hex mode my 13 pin output continues to pass a very faint (and highly distorted) signal even when my mag pickup volume knob is turned to "zero".  In most patches this mag output "leakage" isn't audible to me,  but with most of the Studio Metal patches (which have the COSM amp gain level set to something like 120) I can definately hear it.  Backing the COSM amp gain back to ~100 on these patches seems to make this output inaudible again.  My RR stat does not exhibit similar behavior.  I'm asking Mogan for comment on this as well.

michaiel

Factory patch PowerMan will recreate the symptom for me consistantly. Let me know what you find.....

clamhands

Quote from:  michaiel on May 05, 2010, 02:21:41 PM
Factory patch PowerMan will recreate the symptom for me consistantly. Let me know what you find.....

Tried- Unfortunately I'm not able to reproduce the feedback issues using the Powerman patch using my Ghost system.

michaiel

I have ordered Richards (RMC) V9SF subsonic jack. I will update everyone when it arrives.

clamhands

#74
Quote from:  michaiel on May 12, 2010, 07:36:56 AM
I have ordered Richards (RMC) V9SF subsonic jack. I will update everyone when it arrives.

For what it's worth,  VG-99 I used to do my test has the RMC board installed.  I have nothing but glowing compliments for this board when used with the Ghost pickups- it's a great upgrade...even without feedback problems.

Dumb question time...It looks like the part you reference is for a PRS trem saddle...If you're hearing a ringing feedback that muting the strings with your palm doesn't kill,  is there a chance that the "feedback" you're hearing is being created by the trem springs on the guitar vibrating/resonating?  I've had/have problems with spring noise being *very* audible at times with my Ghost pickups and I'm mulling over trying some polymer based "noiseless" springs in place of the steel springs as a result.