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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Magiamusical

It's been some time since any update to this post but I was wondering if someone has done the mod with the buffer to match a passive guitar. Really interested in performing this mod.

Tks,
Godin LGXT, Les Paul Studio w/GK3, JTV89F w/GK3, GR-55

gumtown

I am just about to try this mod on my GR-55, but first I have passed a shielded wire through the desk lock slot rather than drill my GR-55 chasiss (for now).
I want to try my normal PU in four cable method connection (routing via the external preamp, but not have the synth tones coloured by the external preamp.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

Gastric

If you could get a short enough 13 pin patch cable I'd suggest installing everything in an external project box. It'll be way more easier to work on than taking the chassis off the GR-55 each time you want another mod. Today you want a couple 1/4" jacks, tomorrow you want external S1/S2 and GK Vol jacks or even 1/4" to PCM triggering.

SP2333

Would somone mind making me a diagram/schematic showing the inputs. From the pics above i cant make out which is the switched connection etc....

SP2333

Quote from: SP2333 on January 05, 2012, 09:37:12 PM
Would somone mind making me a diagram/schematic showing the inputs. From the pics above i cant make out which is the switched connection etc....

It's all good.  I got it sorted with some minor thinking.   Now I can run my Satchurator in the normal pickup loop.  Sounds perfect. 





Machh_2

Maybe this modification can be done with only one 1/4 jack...
if u use 1/4 jack stereo with switch you can do in/out audio more simple and using a cable "Y" , 1 stereo 1/4 plug one side and 2 mono 1/4 plug the other side. On the 1/4 stereo plug you use the tip to audio in, and the ring to audio out, and the others 2 mono 1/4 plug you use to in/out audio plugged to effects pedals. With stereo jack unplugged the audio bypass by the switch directly to inside GR-55, if plugged diverts the sound straight to the pedals.
I think this way, can avoid noises and some hummings, because the cable can be more short and is one less cable on the floor...
BTW... one less hole on the GR box...
or maybe you can use this solution to in/out audio and S1/S2 switches, so you have only 2 holes on GR55 rather than their 4 holes...

modification can be a viable,
just a suggestion

SP2333

Doesnt really matter about the holes because if you do it correctly as you can see in the pics above it looks stock.

alanw57

Hi Beirne - you look like you know the GR-55 like the back of your hand.  I've just bought one and it's driving me crazy.  I want to send a mixture of regular guitar pickups AND a modeled guitar sound to the guitar out ONLY - not the main outs.  Is this possible?

Al

romero

I have a few questions about this mod. Where is the signal inserted in the chain? If i use a pedal with a buffer or active pickups there is no need to add a buffer mod? also has anyone done the s1/s2 ext mod yet? and has anyone done the buffer mod and if so would you mind sharing the details? I have a brian moore with passive duncans and sometimes it would be nice to just use some effects from the gr-55 with a 1/4" input and also throw my damage control womanizer in the loop to sweetin it up.

Thanks

celestmark

I'll pay any reputable person who can mod my GR to the best level of this mod... please PM me.

This is so badly needed by Roland, but they most likely have financial interests as to why it wasn't implemented!  >:(

randyrocker

Quote from: audiotrax on June 06, 2011, 06:05:52 AM
Beirne: I just checked out your Intangibles page - the album cover artwork is priceless!  The robot even has a belly "button".  The music is good too  :)

This is awesome man I could do some crazy stuff with this with my Variax and my HD500 and the GR55 do yo have the scematics for the wiring and how to do it I dont want to screw up the GR55?

Man awesome :)

Practus

Quote from: romero on February 22, 2012, 08:45:27 PM
I have a few questions about this mod. Where is the signal inserted in the chain? If i use a pedal with a buffer or active pickups there is no need to add a buffer mod? also has anyone done the s1/s2 ext mod yet? and has anyone done the buffer mod and if so would you mind sharing the details? I have a brian moore with passive duncans and sometimes it would be nice to just use some effects from the gr-55 with a 1/4" input and also throw my damage control womanizer in the loop to sweetin it up.

Thanks

Valid questions here... Would like to know where is the signal inserted in the chain as well... And it would be awesome if someone with the mod could do a video with some samples of what was accomplished with the mod... It seems to be a very good mod indeed...Just curious with the practical results, though...

Hey gumtown... did you do the mod by now?

Cheers
Red Ibanez RG150 (with GK-3 and Fernandes Sustainer FSK-101)
Honey Burst Epiphone LP Standard
Black Fender Standard Strat "a la Blackie"
POD HD500
GR-55
FRFR KRK Rokit 5 Monitors

Elantric

QuoteWould like to know where is the signal inserted in the chain as well..

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.


Practus

Quote from: Elantric on April 25, 2012, 12:31:07 PM
This thread should help explain

Actually I was checking those threads out a few minutes ago... But I guess my electronic knowledge is very poor to understand properly those diagrams... Think I'll have to study a lot more on the subject...
Red Ibanez RG150 (with GK-3 and Fernandes Sustainer FSK-101)
Honey Burst Epiphone LP Standard
Black Fender Standard Strat "a la Blackie"
POD HD500
GR-55
FRFR KRK Rokit 5 Monitors

gumtown

Quote from: Practus on April 25, 2012, 12:27:09 PM
Valid questions here... Would like to know where is the signal inserted in the chain as well... And it would be awesome if someone with the mod could do a video with some samples of what was accomplished with the mod... It seems to be a very good mod indeed...Just curious with the practical results, though...

Hey gumtown... did you do the mod by now?

Cheers
The signal is inserted at the front of the analog chain before any A/D conversion.
This modification breaks into the signal coming from the normal pickup of the guitar.
With nothing plugged in the guitar signal carries straight through (normal GR-55),
when something is plugged into the 'send', the signal is 'Tee' only.
when something is plugged into the 'return', the through signal is interupted.

I use mine in two ways,
For practice, i plug a Tech21 character pedal (preamp/OD pedal) into the loop, you can plug any external pedals you want in this loop.
For gigs, i use the GR-55 connected in four cable method (4CM) where the 'send' goes to a guitar amp 'input', the guitar amp Fx send then goes back into the GR-55 loop 'return', this uses the preamp section only of the external amp on the normal pickups signal, and does not color the PCM tones from the GR-55.
Then the GR-55 L/Mono Output goes to the external amp's Fx return, to use the amplifier section of the guitar amp.

This mod works very well for me.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

imerkat

Hey guys!

For those of you that use this mod with preamp, do you use the cab sim of the Gr-55 or find that only a real cab gives you your tone? Or do you have a cab sim before it goes back into the Gr-55? and what preamp do you use and why??


Elantric

This mod is primary targeted to folks who wish to use their regular "non 13 pin" electric guitars with the GR-55 - to take advantage of the GR-55's COSM AMP  / Cab modelling and FX - and then feed fullrange flat response Amplification systems with the GR-55 main Outputs.


imerkat

not according to the subject line  :). I know Gumtown is using the 4CM system. He turned me to this a while back

gumtown

Quote from: imerkat on July 03, 2012, 10:44:08 AM
Hey guys!

For those of you that use this mod with preamp, do you use the cab sim of the Gr-55 or find that only a real cab gives you your tone? Or do you have a cab sim before it goes back into the Gr-55? and what preamp do you use and why??
While using this mod, I have the GR-55 preamps and cabs switched off, and the output select remains on line/phones.
Also have a set of patches without the preamps, and a duplicate set with the internal preamps and cabs enabled.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

imerkat


concordal

One post above says that this mod calls for a switched normally closed ¼" mono jack.

I did track down switched NC jacks with a plastic bushing.  But which one?

Mouser shows two:

Switchcraft NL112BX
Datasheet says "Tip Closed Circuit"  or "Single Closed Circuit"
(See http://ca.mouser.com/ProductDetail/Switchcraft/NL112BX/?qs=sGAEpiMZZMv0W4pxf2HiV6YB0RWJpyofYBLMQPmSxsc%3d )


OR


Switchcraft NL114BX 
Datasheet says "Tip and Ring Closed Circuit"  or "Double Closed Circuit"
(See http://ca.mouser.com/ProductDetail/Switchcraft/NL114BX/?qs=sGAEpiMZZMv0W4pxf2HiV6YB0RWJpyofmSz5Y6JPNlc%3d )

Can anyone tell me which is the correct jack?  Many thanks in advance!

Elantric

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


cedric

Hello everyone,

I would like to plug a normal guitar jack into the GR55 to use the cosm sound and effect. Can I buy an adaptor somewhere? Any suggestions?

Thank you very much,

Best regards,

Cédric

stelemay

Just plug the guitar cable(the one that is not equiped with the GK pickup) into the 1/4 jack of the GK-3 input, that's what i do when i want to play my second guitar that has not the GK-3 Roland pick-up, you can even use both guitar at the same time with an other guitar player!