GR-55 -Modification to use as multi effects with any guitar

Started by baratijas, October 04, 2011, 05:08:31 AM

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baratijas

It is a very simple modification, one must add an input jack and solder the PCB GK, see photos.

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(En español)
Hola, es una modificacion bastante sencilla para usar el Roland GR-55 como multiefectos/pedalera estandar con cualquier guitarra, es decir sin tener que usar una pastilla del tipo GK.

Por tanto no tendremos acceso a las funciones que utilicen las pastilla GK, pero tenemos la ventaja de poder usar los efectos y simulaciones de amplis con cualquiera de nuestras guitarras electricas, seria como tener una version reducida de la GT-10. El modulo afinador no funcionaria en tal caso y habra que usar un afinador externo.

Se trata de añadir una entrada de jack y esta conectarla a la plaquita de circuito impreso donde esta alojado/soldado el conector GK. La modificacion no afecta para nada al GR-55

No hace falta esquema alguno, una imagen vale mas que mil palabras.

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(English)
Hello, it's a fairly simple modification to use the Roland GR-55 as a multi / standard with any guitar pedal, ie without having to use a GK type pickup.

Therefore we will not have access to the functions that use the GK pickup, but we have the advantage to use the effects and amp simulations with any of our electric guitars, it would be like having a reduced version of the GT-10. The tuner module will not work in this case and we will have to use an external tuner.

It is adding a jack input and connect it to the plate this printed circuit which is housed / soldier GK connector. The modification does not affect the GR-55

Needless to any scheme, an image is worth a thousand words.




Elantric

Realize to use this mod with a guitar or bass with passive pickups, you must insert an active buffer amp between your instrument and the new 1/4" input jack.

any Boss compact pedal will work as an active buffer amp, and simply set the Boss pedal in "Bypass".


Read the GR-55 Gk Input Reference thread
https://www.vguitarforums.com/smf/index.php?topic=12249.msg89023#msg89023

prsrick

Yes, Thanks To Elantric,  it worked with the buffer much better.
I thoguht Boss pedal is true bypass, but looks like it is gone through buffering stage.

Elantric

QuoteI thought Boss pedal is true bypass

Nope - never have been, and never will be ;)

baratijas

Quote from: Elantric on October 04, 2011, 09:50:12 AM
Realize to use this mod with a guitar or bass with passive pickups, you must insert an active buffer amp between your instrument and the new 1/4" input jack.

any Boss compact pedal will work as an active buffer amp, and simply set the Boss pedal in "Bypass".

OK, thanks.

I use guitars with passive pickups without an active buffer insert my instruments and amp Between the new 1 / 4 "input jack, and my guitar work reasonably well. But my guitars have passive pickups with high output  ::)


But it is good idea to use an active buffer  ;)...

IC1b its the buffer in the schematic of GK2 Pre Amp Board

gumtown

Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

baratijas

True, it sucks tone.

Elantric solution:


My solution:
http://www.till.com/articles/GuitarPreamp/



paults

Nice job! Is the 3 meg resistor on the other side of the connector, or did you omit it from your circuit?

baratijas

Quote from: paults on October 07, 2011, 03:10:25 AM
Nice job! Is the 3 meg resistor on the other side of the connector, or did you omit it from your circuit?

My R1 is a 3,3 meg resistor, C2 no is necesary, a use a 9V battery as power supply

Gastric

Why not build a 7V compatible buffer and slave it off the GK power and install it all inside the chassis?

Based on my experience if you use a BOSS pedal as a buffer it always needs to be last in your chain right before the GR-55.

baratijas

Quote from: Gastric on October 07, 2011, 02:47:52 PM
Why not build a 7V compatible buffer and slave it off the GK power and install it all inside the chassis?

Based on my experience if you use a BOSS pedal as a buffer it always needs to be last in your chain right before the GR-55.

You say that I use +7 V from pin 12 of the GK pickup., but I think it's best to use 9V as power supply  ::)

Gastric

Quote from: baratijas on October 08, 2011, 09:40:40 AM
You say that I use +7 V from pin 12 of the GK pickup., but I think it's best to use 9V as power supply  ::)

I wasn't saying, I was asking why you didn't simply pull the 7V from the GK internally? Thus no 9V battery necessary.

baratijas

Sorry, my English language knowledge is very poor, I use the google translator.

I think it's best to use 9V, since the buffer circuit is designed to work with 9v, work with less voltage (7V) can cause signal clipping.

master613

it,doesn`t matter to slave your circuit to the interal +7v supply,just change your resistor value to match the drain current. ;)

augie1

why would it not work just to use and old unused or extra gk3 or gk2 with a short 13 pin cable attached, leave it beside the gr55, or mount it on a small pad, and then plug our regular guitar cord into the  guitar in of the gk3??? would this not solve all the buffering problems, and even allow a wireless guitar setup if desired? is there a limit on how long of a cable can be used to go from the guitar to the gk2/gk3 ?? I have several gk2 gk3 and yamaha midi pickups laying around, this seems like a no brain er?? I realize the retail price of a gk3 compared to adding a 1/4 guitar jack to the gr55 is a little more money, but if you the have to buy a buffered pedal, and 9 volt batteries often, the used gk3 idea does not seem all that bad to me. In fact if it were mounted in  nice sturdy pedal fashion, or a sturdy box, it could easily set next to the gr55. then we could even run into some effect pedals if needed or desired, before going into the gk3. then you have even more choices, any reason this will not work, or be impractical, I really want to know, and learn... thanks...

Elantric

Quote
why would it not work just to use and old unused or extra gk3 or gk2 with a short 13 pin cable attached, leave it beside the gr55, or mount it on a small pad, and then plug our regular guitar cord into the  guitar in of the gk3??? would this not solve all the buffering problems, and even allow a wireless guitar setup if desired? is there a limit on how long of a cable can be used to go from the guitar to the gk2/gk3 ?? I have several gk2 gk3 and yamaha midi pickups laying around, this seems like a no brain er?? I realize the retail price of a gk3 compared to adding a 1/4 guitar jack to the gr55 is a little more money, but if you the have to buy a buffered pedal, and 9 volt batteries often, the used gk3 idea does not seem all that bad to me. In fact if it were mounted in  nice sturdy pedal fashion, or a sturdy box, it could easily set next to the gr55. then we could even run into some effect pedals if needed or desired, before going into the gk3. then you have even more choices, any reason this will not work, or be impractical, I really want to know, and learn... thanks...

Sure why not - that would work too.

But most guitarists i know I already have a spare Boss pedal, and not a spare GK-3

So for the cost of drilling a hole and mounting a TRS 1/4" switching jack ($6) its easy to add an external Normal Guitar FX loop that also acts as a 1/4" normal guitar jack.
 

Other threads on this same topic are here:

GR-55 FAQ: TOP THINGS TO KNOW
https://www.vguitarforums.com/smf/index.php?topic=4006.0



mitchyboy

Hi
I am using a Godin LGXSA and a gr55 . I also use an Italia Rimmini 12 string.

I have been using the Godin with the Gr55.s fx using the stereo outs and havebeeen pleased so far.
My question is ,using a box and 2 female 13 pin sockets and a 1/4 " jack socket.
Could i break into the 13 pin wiring and use a a/b dpdt switch to swap from Godin to Italia and use the GR55 fx?
This would save me using 2 amps
Regards
Mitch

Danno

Regarding this mod, I can't quite make out exactly which pins to solder the two wires from the jack to.  Also, my understanding from this post is that with any Boss (or similar) pedal between the guitar (with passive pickups) and the new input, any guitar can use the GR55's reverbs, chorus, COSM; just not any of the functions that use the individual string pickups.  Is that correct?

When soldering to the circuit board is there anything that should be heat-sinked in order to avoid damage to components on the board?

Thanks in advance for any help!

Regards,

Dan

gumtown

Quote from: Danno on December 31, 2014, 03:53:46 AM
Regarding this mod, I can't quite make out exactly which pins to solder the two wires from the jack to.  Also, my understanding from this post is that with any Boss (or similar) pedal between the guitar (with passive pickups) and the new input, any guitar can use the GR55's reverbs, chorus, COSM; just not any of the functions that use the individual string pickups.  Is that correct?

When soldering to the circuit board is there anything that should be heat-sinked in order to avoid damage to components on the board?

Thanks in advance for any help!

Regards,

Dan

The Jack ground solders to the board ground (closest pin to the chassis, furtherest pin in picture),
the jack socket tip solders on to the pin 7 (7th pin from front view in picture).

There is no need to heatsink anything, just use a sensible sized electronics soldering iron (25~40 watts) with resin cored solder,
and not a blow torch.

And as always, use a grounded antistatic work mat and wrist strap when working on electronic equipment  (although I am guilty of not always doing that).
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

Danno

Thanks for the reply GT.  Can you comment on the other questions in my post about exactly what functions this jack will give to standard guitars plugged into it?

- Dan

gumtown

This will not give you PCM synths or instrument modelling,
but it will give you NS, Amp & cabinet modelling, MOD effects, MFX effects, chorus, delay, reverb.

My GR-55 has one step further with two jack sockets, where the pin 7 circuit is intercepted (wire cut) so as well as a guitar input, it also works as an external preamp/effects insert loop for the normal pickup tone.
I like to have real knobs to provide instant level/tone with a Tech21 preamp pedal or GT-100 multi effects in the loop.

One of the two jacks is a switch type, so if nothing is plugged in, the GR-55 works business as usual. 
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

Danno


Toby Krebs

I use mine every time I use one of my GR55s. No regrets about modding them as I will never sell them.

Danno

I agree Toby.  The longer I own mine the more I find I can be creative with it.  Pretty cool toy and with this mod I'm thinking about selling most of the pedals I no longer use.