GR-55 guitar pickup input output fx loop Mod with Pictures!

Started by Beirne, June 05, 2011, 04:13:31 PM

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Elantric

Yes

Could use the same strategy shown here








Toby Krebs

All I want to do is to insert say a Visual Sound Jekyll and Hyde distortion/overdrive pedal into this modded loop and have overdrive/distortion and the GR55s' wah(which I like) available all the time in every patch using of course my mag pickups. Yes I will have to assign and turn on/off things in each patch to do this. A severe limitation of the GR55 as a stand alone unit is the inability to use an overdrive distortion and wah at the same time. I believe the internal wah of the GR55 is still in the right place in the chain to do this the way I want to. If not I will put one of my real wahs in front of the Visual Sound. I also have a BK Butler Real Tube pedal sitting around that sounds amazing. I am going to give this simple use of this mod a try and let you know how it goes.

Toby Krebs

Installed the second switching jack. Bundled the GR55 back up for testing and inserted my 1980s BK Butler Real Tube pedal in the loop. Plugged GR55 mono out into one full range PA cab. Using a Jeff beck patch I wrote I am happy to report that it sounds very good.Feels good too(probably the tube in the Real Tube pedal). That was with a guitar with passive pickups. Tomorrow I will test it with a Boss Compressor and then a Visual Sound Jekyll and Hyde overdrive /distortion in the loop. This will make the GR55 a much better stand alone cover gigging unit for me as I can now use my dist/od stomps in front of the GR55s amp modelling and time based effects.Very Cool!!! Thanks to all for the info-photos and discussions!

CodeSmart

Throwing in an ad here 8) If you don't want to drill holes in your GR-55 you can also get the effects loop + 4 buffered inputs using the GKMX-41 guitar switcher.
https://www.vguitarforums.com/smf/index.php?topic=9143.0

I tend to connect my Marshall amp directly to my GKMX Send Jack. Less digital noise...regular pups never reach the GR-55, also I believe I get more highs).

But I got more gear than I need...and I like it!

Toby Krebs

Thanks CodeSmart. I have a newer black GR55 that I will leave stock and may possibly want one of these GKMX-41 switchers with it. The one I hacked I had gigged extensively with and made my money back a few times already with. I will see if the switcher will work for me.

Tek

I just installed the FX loop mod and am very happy with the results. Much less noise than the stock guitar out jack. I'm using the send to feed my Eleven Rack. Sounds great! Thanks to all who contributed! I have been lurking around for quite some time now and really appreciate all the effort put into this forum. Most of this info I would probably never find out about. I've gotten to where I check the forum almost every day, just to see what's new. Anyway... thanks again!

Toby Krebs

GR55 and Eleven Rack with this mod should absolutely kill! Glad it's working for you.

Elantric

QuoteMost of this info I would probably never find out about. I've gotten to where I check the forum almost every day, just to see what's new. Anyway... thanks again!

Tek - Welcome to the forum! Tell your friends! 

SLICK

I'm just in the process of repurchasing a gr55 after missing the brass sounds and trying to downsize my cumbersome analog digital hybrid rig so this mod is pretty interesting to me.
I assume that if people were hesitant to mood their £500 bit of kit you could do the same thing by just hacking up a 13 pin cable?
Parker fly deluxe,
Roland GR-55,
Laney LC30II

CodeSmart

Hacking up a cable is not really the same thing (even though it probably works if you put an external pedal/buffer to it) as adding an operational amplifier circuit for proper impedance of input and output. You should read the complete thread as Elantric pointed towards.
But I got more gear than I need...and I like it!

SLICK

Thanks.
I have read the whole thread ( a number of times) the majority of which is about a non buffered "simple" way of breaking into the pickup feed of the guitar signal.
I was only pointing out that if people are hesitant to drill holes in their GR 55s then you could presumably do the same thing by splicing a couple of connectors into a 13 pin cable.
Parker fly deluxe,
Roland GR-55,
Laney LC30II

CodeSmart

Quote from: SLICK on November 27, 2013, 01:45:11 PM
Thanks.
I have read the whole thread ( a number of times) the majority of which is about a non buffered "simple" way of breaking into the pickup feed of the guitar signal.
I was only pointing out that if people are hesitant to drill holes in their GR 55s then you could presumably do the same thing by splicing a couple of connectors into a 13 pin cable.

In that case, if taking about unbuffered access, you are completely right  ;)  This would be the cheapest way to access the GTR (pin 7) signal without drilling the GR.
But I got more gear than I need...and I like it!

Beirne

Just to clarify about my original post...
This is meant as an FX LOOP to add stompboxes and or rack effects to the direct guitar pickups signal...that is mixed INTERNALLY in the GR55 with the GK pickup and synths.
.. Which means you should patch a stompbox like a compressor or something to buffer the raw guitar signal IF YOU USE MAGNETIC PICKUPS . All my guitars and basses have onboard PREAMPS/tone so the guitar signal is hot enough to plug straight in if needed without any effect boxes.
www.intangiblesny.com
www.facebook.com/intangiblesband

gumtown

The normal guitar pickups are buffer through the GK-3 anyway,
the output is a low impedance at around 100 ohms, which helps minimise induced noise through the GK cable.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

kellynorris63

Is it possible to hijack the guitar signal and run it to a processor while passing it on through to the GR-55?  I'm interested in taking the hijacked signal and running it though my Eleven Rack then to ch 1&2 on my mixer.  Then take the output of the of the GR-55 and run it to ch 3&4 on my mixer. That way I can have two distinctive sounds.

gumtown

Quote from: kellynorris63 on January 29, 2014, 05:49:12 PM
Is it possible to hijack the guitar signal and run it to a processor while passing it on through to the GR-55?  I'm interested in taking the hijacked signal and running it though my Eleven Rack then to ch 1&2 on my mixer.  Then take the output of the of the GR-55 and run it to ch 3&4 on my mixer. That way I can have two distinctive sounds.
The simplest way would be to use the GR-55 "Guitar Out" port, giving you either/both the Dry normal guitar and modeled guitar tones.
Or you can 'mod' your GR-55 box and 'tap' into the normal guitar signal before it enters the GR-55 circuitry.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

kellynorris63

Thanks Gumtown. I've decided to mod the GR-55 with a send a receive. That way I can send the hijacked signal to my Voodoo Labs GCX guitar input then coming out the guitar output on the back (buffering the signal) then use one the loops as an A/B box between the GR-55 and the Eleven Rack. What that will allow me to do is keep the GK-3 in Mix mode all the time and use the Ground Control Pro to choose between sound sources.  Then I'll be able to call up the patches and switch between sound sources with one button. Should be interesting..

steph069

Quote from: Elantric on April 25, 2012, 12:31:07 PM
This thread should help explain
https://www.vguitarforums.com/smf/index.php?topic=3793.0
https://www.vguitarforums.com/smf/index.php?topic=3793.0




and here is the GK-2A schematic - note that Pin#7 is the "Normal guitar" input path - and that is the signal where these insert jacks are being installed in the posts above.





Hi all,


I am about to start this mod on my GR55:

I have 2 questions for Elantric
1) Can I use a UA741CN ST micro electronics as the ampOp as I have few in hands or should I definitely go fro the TL072B (also is the B important, or any like TL072CP works)
http://www.mouser.fr/ProductDetail/STMicroelectronics/UA741CN/?qs=wnz1wyZ0ZnWrt9WAQ171Aw==

2) How can I supply the Voltage (+7V and -7V) on the AMP OP (can I use some pins on the GK connector or should I supply it from a battery?

Thank you for your help


Elantric

1) 741 opamp. Will be ok.

2) GK13pin Input
pin 12 = +7v, pin 13= -7v

steph069

Thanks a lot for the so quick answer (appreciate as I am currently sorldering ;))


greekjgg

I get the first input is so you can plug a "regular" guitar into the GR55. Can't believe I'm just not reading this thread.

Regarding the 2nd input that is used for external effects on the same "regular" guitar.

1. Couldn't you just plug the guitar into those effects first then into the input?

2. Wouldn't that also act as the "buffer" that is needed too?

3. Is there a way to use external effects on the GK controlled guitar? Outside of adding them to the "guitar out" jack afterwards? I would like to use a harmony/pitch shift pedal for some solos on some songs we cover but would prefer to keep them in the same mix vs the "guitar out" jack running to another input somewhere.

Setup:
Homemade EVH Frankenstrat with built in GK3
GR55
Rocktron Talkbox
TC Helicon Voicetone C1
Tech 21 Power Engine 60

Elantric

Quote1. Couldn't you just plug the guitar into those effects first then into the input?

Yes - many do  - anyone can already use normal FX for normal guitar signal path by inserting Guitar stomp pedal FX between the normal guitar 1/4" output jack and the GK-3's 1/4"  Input jack.

Quote2. Wouldn't that also act as the "buffer" that is needed too?

Yes  - this is described in the GR-55 Input Mod thread here:

GR-55 FAQ: TOP THINGS TO KNOW
https://www.vguitarforums.com/smf/index.php?topic=4006.0
GR-55 Mods
*  Add a Normal Guitar Input jack on your GR-55
https://www.vguitarforums.com/smf/index.php?topic=4624.0




Quote3. Is there a way to use external effects on the GK controlled guitar?

Use an RMC Fanout box which has 1/4" TRS Insert points for each of the 6 string signals - but know that this will impact Guitar to PCM and Guitar to MIDI in a severe negative fashion, and probably deliver unexpected results for COSM modeling too.
http://www.rmcpickup.com/fanoutbox.html


greekjgg


https://www.vguitarforums.com/smf/index.php?topic=4624.0[/i]



Use an RMC Fanout box which has 1/4" TRS Insert points for each of the 6 string signals - but know that this will impact Guitar to PCM and Guitar to MIDI in a severe negative fashion, and probably deliver unexpected results for COSM modeling too.
http://www.rmcpickup.com/fanoutbox.html


[/quote]

For #3, I may have mis-stated my question. I don't want to actually run a GK equipped guitar on a separate effects processor,  I'm merely wondering if there is a way to "add" external effects besides the "guitar out" jack? Basically similar to the external effects loop mod created for a "regular" guitar but for the GK equipped guitar? Ideally I would have any generic patch I created for my GK equipped guitar but want to add a harmony pedal into the mix but I don't want to have to run that from the guitar out jack separately to my amp as I have everything running out of the L/R channels to the mixer.
Setup:
Homemade EVH Frankenstrat with built in GK3
GR55
Rocktron Talkbox
TC Helicon Voicetone C1
Tech 21 Power Engine 60

greekjgg

Can I purchase 2 of these and be done or do I have to find the version that isn't "switched" also?

Quote from: Elantric on September 12, 2012, 04:01:01 PM
I prefer this type of isolated 1/4" Phone TRS switching Jack

These are similar to the old Re-An  / Cliff UK style jacks used by Marshall and they are robust and electrically isolated from the Chassis

http://ca.mouser.com/ProductDetail/Amphenol-Audio/ACJS-IH/?qs=sGAEpiMZZMv0W4pxf2HiV35EdOeKop2q0bVDXJUTLs0%3d


Amphenol # ACJS-IH

Mouser# 523-ACJS-IH


Setup:
Homemade EVH Frankenstrat with built in GK3
GR55
Rocktron Talkbox
TC Helicon Voicetone C1
Tech 21 Power Engine 60

Elantric

I would just buy these switched jacks and simply not connect the switch elements  - order in bulk, save money and one Jack type in your parts bin works for several different projects