Graph-Tech Hexpander HELP

Started by Gaustu, November 24, 2017, 01:13:15 PM

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Gaustu

Hi

Something wrong is going on with my sound (clicks hearable when use up/down butons)

Does somebody know if there  -7 v has to be arrived on the hexpander module??? as same as +7 v

After this small module that is mounted on 13-pin jack I do not see -7v,  but +7v  only.
I see  -7v right on this module on the #13 pin and on some transistor.

Is there something wrong?
Parker PDF85 modified: Sustainiac, SD TB-4, Piezo Hexpander 13 pin out.
GR-55 mod with 13 din thru, 6 analog outputs D-Sub => Presonus FS Mobile  8 analog inputs.
NI Reactor matchHEX Guitar Framer Ensemble custom.

gvidelock

#1
Thanks for attaching the picture.

Yes -7V is required.

It looks like there's no solder on one of the pins where the ribbon cable attaches to the circuit board.

If you have a voltmeter or multimeter you can check if that is the pin that carries -7V, but in any case it should be soldered.

-------------------------

Godin Spectrum SA
Godin Freeway SA
Fender Telecaster with Ghost and Hexpander
Fender Stratocaster with internal GK3 with Synth-Linx
Warmoth custom with internal GK3
Boss SY-1000
Roland GR-55
Roland GP-10
Katana 100W Head

Gaustu

#2
Hi gvidelock
thank you a lot for your reply!

I am sure this not soldered pin is NOT for -7v. This pin is grounged. And it's made so for proper plugging the connector into the slot (to not do casual reverse)
And there are three grounded pins in these rows.

I have a multimeter and made all possible checking in this module. Looks like everything is not damaged.

I sent a mail to Graph-Tech on saturday and I wait for answer soon after this weekend.

You said that -7v required...  Why you sure?
I heard that in Line6 modules they use no minus side and use positive side only, then divide it using a middle point as a ground...
It would be great if someone got this module out and check all these 16 pins -  is there - 7 v ?

Parker PDF85 modified: Sustainiac, SD TB-4, Piezo Hexpander 13 pin out.
GR-55 mod with 13 din thru, 6 analog outputs D-Sub => Presonus FS Mobile  8 analog inputs.
NI Reactor matchHEX Guitar Framer Ensemble custom.

sixeight

I would definitely soldering the pin first and see if it solves the problem. Gvidelock is right: it should be soldered. The way it is now it will give a bad connection. It could be ground, or it could solve your problem. It doesn't hurt either way...

Gaustu

#4
Look here

http://www.graphtech.com/products/brands/ghost/product-detail/pd-0512-00-ghost-interface-wiring-harness?id=cb53f105-b31d-40d4-8e8a-f5581b2acd4d


This is description for a 16-pin Harness that connects the Hexpander MIDI Interface board to the 13-pin Jack:

The PD-0512-00 connects the Hexpander MIDI Interface board to the 13-pin Jack. 12 inches long. This harness has 16 holes, and on each end one hole is blocked to "key" the connector so it can't be plugged into the Hexpander or 13-pin jack the wrong way.

There is nothing to solder because there is blocked hole of connector over this "unsoldered" point.
Parker PDF85 modified: Sustainiac, SD TB-4, Piezo Hexpander 13 pin out.
GR-55 mod with 13 din thru, 6 analog outputs D-Sub => Presonus FS Mobile  8 analog inputs.
NI Reactor matchHEX Guitar Framer Ensemble custom.

gvidelock

Hi Gaustu,

I saw that in the manual and was putting together my reply when my system crashed...

I also am likely wrong about the -7V since the Acousti-Phonic is designed to work from a single 9V battery. They probably designed all of the circuitry to work from a single voltage.

Without a visual inspection of the circuit board and connections I can't think of any reason that the clicking is happening on the UP / DOWN switches.

On a GK-3 the buttons (or switches) take the signal to ground (pins 10 and 11 on the 13-pin DIN). If there was a short between the switches and an audio signal I would think there would be other issues with the audio.

Sorry for the misinformation.

   ...Gary
-------------------------

Godin Spectrum SA
Godin Freeway SA
Fender Telecaster with Ghost and Hexpander
Fender Stratocaster with internal GK3 with Synth-Linx
Warmoth custom with internal GK3
Boss SY-1000
Roland GR-55
Roland GP-10
Katana 100W Head

admin

#6


Most GK 13 preamps ( Roland, RMC, LRBaggs ) employ +7VDC and -7VDC , (14 volts) sourced from the connected GK processor ( GR55, GP10, VG8, VG88, VG99 GR33 , etc)


Suggest RTM
http://www.graphtech.com/docs/default-document-library/ghost-installation-manual.pdf


QuoteIs there something wrong?

Why is there a white wire soldered on the GK 13 jack board?
And many pins are desoldered

If this is a used ghost expander, it appears to have been modded with poor soldering


Gaustu

Hi admsustainiac
I examined that part of my harness that seems like damaged. Really, there is one small peace of tin !!!
But alas, no damaged insulation! I have cleaned it now.

9 pin was unused as you know and I made a little mod in my guitar with additional knob-controller through this #9 pin.

And why you say there many pins are desoldered ?  I have no one  ???

Well, I disconnected this module from hexpander main board and measured all voltages on all 16 pins as shown on my pic.

As we see, there is no negative voltage at all. Since it is on diodes shottky BEFORE pins in there - - 7v
I am puzzled!


Parker PDF85 modified: Sustainiac, SD TB-4, Piezo Hexpander 13 pin out.
GR-55 mod with 13 din thru, 6 analog outputs D-Sub => Presonus FS Mobile  8 analog inputs.
NI Reactor matchHEX Guitar Framer Ensemble custom.

Gaustu

#8
Quote from: gvidelock on November 26, 2017, 02:50:51 PM
...I also am likely wrong about the -7V since the Acousti-Phonic is designed to work from a single 9V battery. They probably designed all of the circuitry to work from a single voltage.

   ...Gary

Gary, yes, but it is just for  Acousti-Phonic +9 v. I guess Hexpander uses both voltages.
Quote
On a GK-3 the buttons (or switches) take the signal to ground (pins 10 and 11 on the 13-pin DIN). If there was a short between the switches and an audio signal I would think there would be other issues with the audio.
Well. in Hexpander these S1, S2 buttons work the same -  take the pin 10 and pin 11  to ground.

This is good I have another guitar with GK-2 mounted and I can compare how it works... No any cliks like I have in hexpander. Clicks are very small but are. And I had some experience  long ago when my Axon lost one side of voltage (-7) - the behavior of GK-2 was very similar.

Thank you guys for your help anyway!!! 
I can't wait for an answer from GT. Need to repair my stuff asap, going to have a party!
I hope I will have not pay another 60 dollars for a new module. Maybe there is some minor bug...

PS.  I think there is somewhere the gap in the copper flat track of -7vdc path after diode shottky. Or so.  Because both diodes found to be good
Parker PDF85 modified: Sustainiac, SD TB-4, Piezo Hexpander 13 pin out.
GR-55 mod with 13 din thru, 6 analog outputs D-Sub => Presonus FS Mobile  8 analog inputs.
NI Reactor matchHEX Guitar Framer Ensemble custom.

Gaustu

#9
Still no answer from Graphtech support.
I defined all pins of this small board (except of this one , which should be -7 VDC)
I think if I will manually  connect #13 pin with that undefined by the +7 VDC... Nothing bad will happen :-X
Parker PDF85 modified: Sustainiac, SD TB-4, Piezo Hexpander 13 pin out.
GR-55 mod with 13 din thru, 6 analog outputs D-Sub => Presonus FS Mobile  8 analog inputs.
NI Reactor matchHEX Guitar Framer Ensemble custom.

Gaustu

#10
So the finish line, I got the info from GT and that made sure all is ok with my boards.
They call this board as HEX-HEADER. The scheme they show is mirrored picture from mine own I made.
In mine I was wrong with pin#3, pin#9, pin#14.   Strange, In my board pin#9 appears to be grounded (with multimeter), maybe it's ok...
So, pin#14 (near +7) is for Volume.

They say:
The negative voltage is not expected to appear on the header. It is used on the connector board but not on the main board.

So now I think about my problem like I was worried too much about what I hear and that is my exacerbation of the perception.

I am so curious to know what others could say about that.
Maybe this is Hexpander's flaw? 
As we see on GK-3 schematics there are  capacitors with buttons S1 and S2 which are for eliminating of pops/clicks.

Parker PDF85 modified: Sustainiac, SD TB-4, Piezo Hexpander 13 pin out.
GR-55 mod with 13 din thru, 6 analog outputs D-Sub => Presonus FS Mobile  8 analog inputs.
NI Reactor matchHEX Guitar Framer Ensemble custom.

admin

Graphtech must be using DC blocking caps on each strings preamp circuit, and running on +7 VDC alone means it has much less dynamic range compared to a GK-3 which runs on 14V  ( bipolar +/-7VDC)

from my experience - the Graphtech Ghost Hexpander is the least desirable GK 13 preamp, its noisy, has a lot of hiss, and it points that Graphtech engineers designed this for Guitar to MIDI systems only, and  never considered  folks would connect the Ghost MIDI Expander to VG-8, VG-88, VG-99, GP-10  COSM hexaphonic Modeling systems  - where the Ghost Hexpander reveals its poor noise floor.  Its like buying an expensive stereo , then running a cheap , poor performing/ noisy phono preamp full of hiss for your turntable

Gaustu

Quote from: admsustainiac on November 28, 2017, 02:14:31 AM
Graphtech must be using DC blocking caps on each strings preamp circuit, and running on +7 VDC alone means it has much less dynamic range compared to a GK-3 which runs on 14V  ( bipolar +/-7VDC)

Yes, really. When I compare both, the difference is. But not 2 or 1.5 times worst. Some more noisy, but yet not so bad. BTW I use additional shielding for each of 6 wire right after the saddles.
If not to use very hard-driven algorithms, it's ok. And if to use acoustic modeling algos they sound even more interesting over magnetic setup.
Parker PDF85 modified: Sustainiac, SD TB-4, Piezo Hexpander 13 pin out.
GR-55 mod with 13 din thru, 6 analog outputs D-Sub => Presonus FS Mobile  8 analog inputs.
NI Reactor matchHEX Guitar Framer Ensemble custom.

Gaustu

One little thought to close this.
maybe I am really too finicky but decided to eliminate tiny clicks of S buttons, added two capacitors paralleled and resistors, like it is in Roland GK, and clicks are gone away completely.

Posted by: gvidelock
QuoteI also am likely wrong about the -7V since the Acousti-Phonic is designed to work from a single 9V battery. They probably designed all of the circuitry to work from a single voltage.
Gary was right.
But I can't understand the design of engineers of Graphtech: If both boards -- Hexpander and Acousti-Phonic are made to work with +polarity only (7 V and  9 v), so why not to get rid of this additional 9V battery and use 7V for a both? I know for sure these ops on Acousti-Phonic would work with 7V as well as with 9. This 7VDC has enough power to drive more ops.
That's why I was sure they use two polarity voltages for Hexpander.
Parker PDF85 modified: Sustainiac, SD TB-4, Piezo Hexpander 13 pin out.
GR-55 mod with 13 din thru, 6 analog outputs D-Sub => Presonus FS Mobile  8 analog inputs.
NI Reactor matchHEX Guitar Framer Ensemble custom.