Author Topic: Build a 1/4" Guitar Input > GK 13 pin out adapter cable?  (Read 10755 times)

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Offline bigfoot

Build a 1/4" Guitar Input > GK 13 pin out adapter cable?
« on: January 28, 2012, 07:27:19 PM »
I'm replacing the 1/4 in jack with a 13 pin jack.  (and will no longer have a 1/4 in jack) Would it be possible to make a short adapter cable (13 pin to 1/4 in), so I could still connect to a conventional guitar cable?  And would there be any down side to that? 

Note, the outer edge of the guitar (Ibanez S series) tapers down to barely 1/2 in, and it would be a major deal to install an additional 1/4 in jack...
« Last Edit: February 12, 2016, 11:14:59 AM by Elantric »

Offline Elantric

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #1 on: January 28, 2012, 09:28:41 PM »
13 pin In > 1/4" Guitar Out adapter  is rather straight forward - but know the normal guitar signal is being passed through an internal opamp buffer (IC4A below) prior to being sent out Pin #7 of the 13 pin Guitar Output jack.
 

But know that many "tone purists" who seek "True Bypass FX" in their guitar signal chain WILL hear and detect the  sonic difference this GK-3 buffer makes on the Normal PU signal output

Quote
Does anyone know if or where I can get a standard 1/4" Guitar Input > GK 13 pin adapter cable?
so that I can use the effects on my GK-55 with other guitars without having to install a GK pickup?

There are a few custom GK 13 pin box adapter available here
http://www.vguitarforums.com/smf/index.php?board=174.0

Or you can build a cable to do this.

On the GR-55  side of the 13 pin connection, Pin # 7 is the  Normal Guitar signal input.

So a cable with a 1/4" male plug on one end ( to your guitar) , and a DIN13 Male plug on the other, with 1/4" plug Tip wired to DIN13 #7 Pin (Normal Guitar input) , and 1/4" plug Sleeve wired to  DIN13 Shell (Ground) gets you half way there.   



Here is a Locking 13pin DIN Male plug for the GK13 end of the cable.

http://www.iec-usa.com/cgi-bin/iec/framefly?;DN13MS-L

http://www.connectworld.net/cgi-bin/cabled/DN13MS-L

ISSUES:  The GR-55's Pin#7 Guitar Input is Low impedance. It relies on an external opamp buffer (Inside the GK-3) .
If you have a guitar with Active electronics or EMG pickups, you should be fine.
But if you want to use a normal stock Strat / Les paul, you will need an external buffer.
Any Boss FX stomp pedal can accomplish this. Even in Bypass mode, the Boss pedals still employ an opamp or FET  buffer to make your signal have lower impedance

The Next issue, No sound on most patches  because if the GK-3 "GK-VOL" control (or equivalent in your Axon/ Yamaha/ RMC / Ghost / LR Baggs  GK 13pin preamp) , you may have to tweak all your GR-55 patches to adjust the level. Also realize 90% of the GR-55 patches DO NOT employ the Normal Guitar Signal, you will have no sound until you Enable the Normal Guitar on each patch.

The next issue is the 1/4" to 13pin adapter cable described above is missing several important "GK-3" features, for example it does nothing for the missing GK-VOL Voltage control (Pin # 8 )

Here is a work-around solution!
Inside the 13 pin plug on your adapter cable, you can add one 240 ohm resistor (243 1%) and one 120 ohm (121 1%) and wire as a voltage divider and feed +5VDC to Pin#8 (Synth Volume  / GK Volume), this makes the GR-55's internal circuitry think an external GK-3 GK VOL control set at "10" exists on the other end of the 13 pin cable
http://www.vguitarforums.com/smf/index.php?action=downloads;sa=downfile&id=80

   
http://www.vguitarforums.com/smf/index.php?topic=4218.0


Back in 2011, I thought I might build and sell this type cable, but I had less than 3 folks interested, and it was deemed too little demand,  = zero sales.

But most just use an unmounted GK-3 Control box, and simply plug regular guitars into the 1/4" Input on the GK-3, then GK out on GK-3 into the GK 13 pin processor.

--

http://www.vguitarforums.com/smf/index.php?topic=13405.msg131406#msg131406
Gumtown wrote>

A centre mounted GK-3B pickup for a 4 string bass would normally use the 4 inner pickup poles, and exclude the 2 outer pickup poles,
so it would use GK 13 DIN pins 2,3,4,5 and common ground on the outer shell.

If you wanted to include a GK Volume control, you could use this simple arrangement in the schematic below, with only a 390 ohm resistor and a 1K ohm potentiometer.
The schematic is for a simple "regular bass jack to GK", but the GK Volume part can be used.

« Last Edit: September 27, 2017, 01:36:32 PM by admsustainiac »

Offline flabergaster

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #2 on: February 24, 2012, 05:19:55 PM »
I'm wanting to do this too. Has anyone successfully sought out the locking 13 pin plug only. I found the CP-1013-ND on Digikey, but it doesn't have the locking clip. I'd like to make a 3 inch 13pin to 1/4 female adapter, in case I ever want to play without the GR55, but I'd rather not spend the $$ on a cord just to cut it up.

Thanks!

Offline bigfoot


Offline Elantric

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #4 on: February 25, 2012, 12:24:39 AM »
Quote
http://www.connectworld.net/cgi-bin/cabled/DN13MS-L

Excellent find ! Good job Bigfoot.

Offline flabergaster

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #5 on: March 01, 2012, 09:25:48 AM »
Awesome! Praise be to Bigfoot!!!!

Offline flabergaster

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #6 on: March 19, 2012, 03:14:26 PM »
Okay, finally got a chance to try this. I ordered the connector found by Bigfoot, and I built two cables with the tip of the 1/4 inch to pin 7, and the sleeve to the outer bracket of the 13 pin cable. It kinda works but produces a ton of hum when plugged into an amp. I'm guessing that there in something in the Connector PCB that is isolating (at least somewhat) the path to ground.

I've noticed in the few pin outs that I have seen for the 13 pin, that pin 12 is labeled +7VDC and 13 is -7VDC. I doubt that they are actually running a 14v system and and using -7 as a ground reference, so I wonder if I tied pin 13 to the shield as well, if the hum would go away. I guess it wouldn't hurt to try it. Since I won't be powering the GK with my adapter I can't imagine any damage to the unit.

Any thoughts? Am I missing something?

If I had a schematic of the GK, I'm sure it would be obvious.

That last line got me thinking, so I searched for the word schematic and low and behold:
http://img141.imageshack.us/img141/5518/gk2schem1da0.jpg

Bad news, it appears that the guitar input goes through an op amp before it gets to the 13 pin connector. This means that a 13 pin to 1/4 inch adapter won't work in and of itself. Anyone who really wants to pursue it will need to add a DPDT toggle switch to bypass the GK board with the normal p/u hot lead and ground. I may just forget about it, because if I'd known going in, I'd have planned my switch layout differently. Oh Well, for any of the rest of you hoping to get around having two jack holes in your GK project guitar, a true bypass with a 13 pin to 1/4 inch adapter is the way to go.
« Last Edit: March 19, 2012, 04:05:59 PM by flabergaster »

Offline gumbo

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  • Changing the 13-pin interface - one Jack at a time
Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #7 on: March 20, 2012, 04:23:28 AM »
Yep..f-g..

..exactly the result I got when I tried this with my RR Strat many moons ago.. ;D

..I came to the same conclusion when I read the schematic..  couldn't see how the signal was going to get out ..perhaps this is a different case if one has another setup with on-board battery power, but....


..alternatively, I guess one could do some wizz-bangedry with pin 9 depending upon what the guitar was going to be plugged into, but I feel that might be fraught with other dangers down the line...   :o



Read slower!!!   ....I'm typing as fast as I can...

Offline sixeight

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #8 on: February 26, 2014, 12:46:37 PM »
I built a 13 pin to jack cable today, so I can play bass guitar over my GR55.
I hooked pin 3 and pin 7 together. This way the modelled guitars are working (though limited in sonic quality) and I have the regular guitar in.

I was hoping to get the PCM sounds working as well. Monophonic, but heck it is a bass. But unfortunately they do not work.... Any clues as to what I am doing wrong? I do recall somebody who had this working, but I can't find the post...
« Last Edit: March 08, 2014, 01:23:09 PM by sixeight »

Offline Elantric

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #9 on: February 26, 2014, 12:58:03 PM »
Quote
so I wonder if I tied pin 13 to the shield as well, if the hum would go away. I guess it wouldn't hurt to try it.

Actually you WILL damage the Host processor (VG-99 / GR-55, etc) if you tie Pin #13 (-7VDC) to the Shell (GND) !

Myself - I find it valuable to build the "GK-13 Snooper" break out board as described here:
http://www.vguitarforums.com/smf/index.php?topic=8391.0
 

In this manner its easy to explore the impact of the separate bandpasss filtering which the Roland units apply to  each of the 6 separate string input signals (GK-13 pins 1,2,3,4,5,6


If you short all pins 1,2,3,4,5,6,7 - that can work - but playing chords delivers results which are both problematic and amusing.
« Last Edit: July 28, 2014, 04:33:41 PM by Elantric »

Offline sixeight

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #10 on: February 26, 2014, 01:44:20 PM »
Thanks for chiming in, Elantric, though that project is quite a lot of work.

In bass mode you can be quite flexible in which string you select by swapping the direction of the pickup and changing the different pickup settings.  I can hear the difference clearly in the resulting sound of the bass models.

But I thought somebody had PCM sounds working from a regular pickup. Has anyone managed to ger this working?
« Last Edit: March 08, 2014, 01:22:16 PM by sixeight »

Offline Elantric

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #11 on: February 26, 2014, 01:57:33 PM »
Actually it should work  to trigger PCM synths - even MIDI (check your GR-55 Patch and verify PCM1, PCM2 are enabled?)
Remember if using a passive instrument with typical Hi-Z output , you need to insert a low impedance Active driver / buffer in front of the GR-55's GK-13 input, signals on pins# 1-7 must be low impedance.

Try inserting any Boss Compact pedal between your Instrument and  your homebrew 13 pin to jack cable.
« Last Edit: February 26, 2014, 02:10:48 PM by Elantric »

Offline sixeight

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #12 on: February 26, 2014, 02:59:08 PM »
Actually it should work  to trigger PCM synths - even MIDI (check your GR-55 Patch and verify PCM1, PCM2 are enabled?)
Remember if using a passive instrument with typical Hi-Z output , you need to insert a low impedance Active driver / buffer in front of the GR-55's GK-13 input, signals on pins# 1-7 must be low impedance.

Try inserting any Boss Compact pedal between your Instrument and  your homebrew 13 pin to jack cable.

I tried that and checked all the options. My guitars are active as well, but no PCM. The only thing I haven't done is adding the resistors for the GK volume pin. Maybe I will try that tomorrow.

Offline Elantric

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #13 on: February 26, 2014, 03:48:33 PM »
Just map the GK Vol control to something other than Volume.

To duplicate a GK Volume pot in "10" Pin8 typically has +5VDC Control Voltage for max volume,

Using two 1% resistors as indicated in schematic below creates a voltage divider and placed +5VDC on Pin 8



243 resistor = 243 ohm 1% Resistor

121 resistor = 121 ohm 1% Resistor

Feed a buffered signal (low impedance) Guitar 1/4" jack wired to DIN13 plug Pin#7
« Last Edit: March 02, 2016, 01:59:44 PM by Elantric »

Offline JolietJake

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #14 on: February 26, 2014, 04:35:40 PM »
If you're not planning on using your tone control you could always do what I did here and stick a jack socket in place of it. You can always replace it later if needed.

Offline BTPA USA

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #15 on: April 24, 2014, 11:09:52 AM »
We would 100% be able to offer this as long as a pinout/wiring diagram is provided (which I believe that I saw above). Let us know if we can help.

BTW The tone knob mod above looks sweet!
Best-Tronics Pro Audio (BTPA)
Custom Audio Cables - 100% Made in USA
Artist Relations / V.P. of Audio
BTPA

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Offline JoBoss

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Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #16 on: January 09, 2016, 10:18:15 AM »
JolietJake - The image posted shows a volume control knob with a 1/4" jack - I'm seeing that for the first time - do such knobs exist..?

Offline chartzog

Re: 1/4" Guitar Input > GK 13 pin adapter cable?
« Reply #17 on: March 01, 2016, 09:18:32 AM »
Actually it should work  to trigger PCM synths - even MIDI (check your GR-55 Patch and verify PCM1, PCM2 are enabled?)
Remember if using a passive instrument with typical Hi-Z output , you need to insert a low impedance Active driver / buffer in front of the GR-55's GK-13 input, signals on pins# 1-7 must be low impedance.

Try inserting any Boss Compact pedal between your Instrument and  your homebrew 13 pin to jack cable.

Hi Elantric,

Would using a DI box achieve the same impedance match as a Boss FX pedal?  But I suppose if this did work the cable would need to be a XLR to 13 pin instead of 1/4" to 13 pin.  Is this possible or am I out in left field?

Thanks.

Offline Elantric

Re: Build a 1/4" Guitar Input > GK 13 pin out adapter cable?
« Reply #18 on: March 01, 2016, 09:40:27 AM »
Active Di - yes, or MXR Micro-Amp.

But I use any typical Boss pedal (like a Tuner or Chorus or DS-1 - does Not need to be "on" because all Boss pedals have active bypass and will buffer the signal to low impedance.


But a much easier method is use an unmounted GK-3 Control box, and simply plug regular guitars into the 1/4" Input on the GK-3, then GK 13 pin out on GK-3 into the GK 13 pin processor.
« Last Edit: March 01, 2016, 09:53:28 AM by Elantric »

Offline wda7700

Re: Build a 1/4" Guitar Input > GK 13 pin out adapter cable?
« Reply #19 on: March 02, 2016, 01:40:52 PM »
Does anyone have a legend for what all the symbols and numbers mean?  I have an idea but don't know much about electronics.  I went to buy some components and they asked me questions I couldn't answer.

Thanks.

Offline Elantric

Re: Build a 1/4" Guitar Input > GK 13 pin out adapter cable?
« Reply #20 on: March 02, 2016, 01:55:19 PM »


243 resistor = 243 ohm 1% Resistor
http://www.amazon.com/Metal-Film-Resistors-Through-243ohms/dp/B00LUDTVXI/ref=sr_1_23?s=industrial&ie=UTF8&qid=1456949454&sr=1-23&keywords=243+OHM+RESISTOR


121 resistor = 121 ohm 1% Resistor
http://www.amazon.com/Dale-RLR07C1210FS-Resistor-121-0-25w/dp/B00B05ZOZK


Feed a buffered signal (low impedance) Guitar 1/4" jack wired to DIN13 plug Pin#7


---
Quote
I have an idea but don't know much about electronics.  I went to buy some components and they asked me questions I couldn't answer.

Most folks skip the DIY approach above and instead just use an unmounted GK-3 Control box, and simply plug regular guitars into the 1/4" Input on the GK-3, then GK out on GK-3 with 13 pin cable into the GK 13 pin input on the GK processor (VG-99 / GR-55 / GP-10, etc).
« Last Edit: March 02, 2016, 05:23:21 PM by Elantric »

Offline Elantric

Re: Build a 1/4" Guitar Input > GK 13 pin out adapter cable?
« Reply #21 on: April 28, 2017, 01:36:46 PM »
http://www.vguitarforums.com/smf/index.php?topic=13405.msg131406#msg131406
Gumtown wrote>

A centre mounted GK-3B pickup for a 4 string bass would normally use the 4 inner pickup poles, and exclude the 2 outer pickup poles,
so it would use GK 13 DIN pins 2,3,4,5 and common ground on the outer shell.

If you wanted to include a GK Volume control, you could use this simple arrangement in the schematic below, with only a 390 ohm resistor and a 1K ohm potentiometer.
The schematic is for a simple "regular bass jack to GK", but the GK Volume part can be used.

« Last Edit: September 27, 2017, 01:35:23 PM by admsustainiac »

Online admsustainiac

Re: Build a 1/4" Guitar Input > GK 13 pin out adapter cable?
« Reply #22 on: November 30, 2017, 10:18:11 AM »
My mini breakout cable and any hex preamp can do all of this and much more.

allows Any Electric Guitar with 1/4" output jack access to a Roland GR-55 synth voices. or VG-8/VG-88/VG-99/GP-10 tones

MINI BREAKOUT CABLE

1  13-Pin line-socket. GK pickup input for recording separate strings. V-synth input with re-amping, re-guitar and re-synth etc.
2  13-Pin GK pre-amp power cable (3M).  Connects to a v-synth (power) or an optional dual 7-9vdc PSU.
3  Separate string output/input jacks (including Pin-7 normal guitar).  XLR and phonos are an option.
4  Extremely durable oxygen-free-copper cable for separate string signals. Fully shielded. Very low cable resistance. 40cms / 16" length. 
5  Pin-8 ‘Phantom power’ with internal in-line socket resistors. Pin-8 allows Any Electric Guitar with 1/4" output jack access to a Roland GR-55 synth voices. Thanks to Elantric.

Price: £75.00GB plus trackable shipping.  3 years warranty with RTB.

Regards,

Bill Bax
http://www.separate-strings.co.uk
« Last Edit: November 30, 2017, 10:22:43 AM by admsustainiac »

 

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