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DIY Stompboxes => Building your own stompbox => Topic started by: Pofper on March 04, 2016, 03:24:52 PM

Title: Building a ga-fc foot controller
Post by: Pofper on March 04, 2016, 03:24:52 PM
hi, I want to build my own foot controller for my Roland 40gx, the problem is that I have no idea what's going inside the pedal, since it have 6 switches and one stereo output jack, and I can't find any resources on internet, no schematics, no circuit photos...  :'(
here's a video showing how this foot controller works:




and a photo of the back panel of the controller:

(http://www.quedesamplis.com/images/GA-FC-1-B.jpg)


and another of the back panel of a Roland Cube 40gx:

(http://www.soundhouse.co.jp/images/shop/prod_img/r/roland_cube40gxb_3.jpg)


If you need any other informations please tell me.
Any help would be great. Thanks  :icon_biggrin: :icon_biggrin:
Title: Re: Building a ga-fc foot controller
Post by: Hatredman on March 06, 2016, 05:47:02 PM
In your video you seem to press a switch in the far right that is never seen. What is it?
Title: Re: Building a ga-fc foot controller
Post by: Pofper on March 07, 2016, 06:58:09 AM
Thanks for your reply, the button you're talking about turns on and off the reverb on the amp.
Here is the buttons fuctions from left to right:
Clean - Lead - Solo - Efx - Delay - Reverb
Title: Re: Building a ga-fc foot controller
Post by: feddozz on March 07, 2016, 08:49:23 AM
I am fairly new to this forum but I want to throw my idea in...
Could you open the unit up and post some pics?
At least we could understand is it's just switching or there is some more complicated circuitry involved.
close up of any boards would help.
There are people here with enough experience and hawk eyes able to spot more things that you can imagine.
Title: Re: Building a ga-fc foot controller
Post by: Pofper on March 07, 2016, 12:22:58 PM
hi feddozz, thank you for replying.
I don't own the foot controller, and I can't find circuits on internet, that's why I'm posting here! the video I attached to this post isn't mine, I just found it on youtube.
But I'm pretty sure it's not a simple switch, it has to have some sort of complicated circuit because it has 6 buttons with different functions and it is connected to the amp through a simple 6.3mm stereo jack.
Title: Re: Building a ga-fc foot controller
Post by: feddozz on March 08, 2016, 04:17:03 AM
Ups, sorry for the misunderstanding. I just can't view youtube videos from work. From one of the replies above it sounded like you shot your own video. So I thought you could open it up.

I found this post (http://www.jazzguitar.be/forum/guitar-amps-gizmos/40395-build-your-own-foot-switch-roland-40-80gx-sleeves-ring-no-effect.html). It is referring to a clone of a Boss F6 pedal which seems to work with the 40GX. It looks like simple switching. Have a look and see what you think.

I read the rules and it seems I can post links to other forums. Please let me know if otherwise.
Title: Re: Building a ga-fc foot controller
Post by: Pofper on March 08, 2016, 04:34:04 AM
Thank you, the link works fine, I've already made this footswitch :P it has a button that toggles between lead and clean and an other that jumps to solo.
Title: Re: Building a ga-fc foot controller
Post by: feddozz on March 08, 2016, 05:53:53 AM
>I've already made this footswitch  it has a button that toggles s between lead and clean and an other that jumps to solo.

Really? Success!!
Title: Re: Building a ga-fc foot controller
Post by: Pofper on March 08, 2016, 02:06:48 PM
Yes, it's a really simple switching pedal!
here is the circuit I've made, the buttons are push buttons, the lead/clean button should be closed initially, the switch decides whether the solo button will be closed on rest or not! if closed, then when you press the clean/lead button you'll go from solo to lead chanel, otherwise, you'll go to clean chanel!
(http://dc591.4shared.com/download/p6RAqZHyba/Untitled-1_copy.JPG?sbsr=e0be69b5f1aa9962131335fa7bdaba4f969&lgfp=3000)
Title: Re: Building a ga-fc foot controller
Post by: Chops9012 on July 04, 2016, 01:01:38 PM
I'm wondering if I could have a go at this too. Have a ga 112 but would really rather not spend £75 for the footswitch. Did anyone have any success?
Title: Re: Building a ga-fc foot controller
Post by: anotherjim on July 04, 2016, 03:31:49 PM
I could be wrong - and would be intrigued to know how it works, but...
I would think that if the ga-fc can read 2 expression pedals and a bunch of switches, then it's probably a digital serial interface. Power, ground and data on the TRS jack? 1-wire serial bus does exist.

Title: Re: Building a ga-fc foot controller
Post by: Beo on July 04, 2016, 08:08:21 PM
Quote from: anotherjim on July 04, 2016, 03:31:49 PM
I could be wrong - and would be intrigued to know how it works, but...
I would think that if the ga-fc can read 2 expression pedals and a bunch of switches, then it's probably a digital serial interface. Power, ground and data on the TRS jack? 1-wire serial bus does exist.

Either Midi through TRS, or some proprietary digital interface.

The manual (linked) doesn't say, but it's definitely a TRS... so digital.
http://roland.com/support/article/?q=manuals&p=GA-FC&id=62468246
Title: Re: Building a ga-fc foot controller
Post by: Chops9012 on July 05, 2016, 06:18:32 AM
All I'd like to build is a basic four button pedal to select each of the four channels.

Any ideas on how to do this?- I'm based in Ireland, the only place to buy the footswitch is thomann, but I'm up for doing it myself for a bit of craic.
Title: Re: Building a ga-fc foot controller
Post by: giglesias on August 02, 2016, 02:41:00 PM
Hi everyone! I'm from Argentina and I've just bought a Roland Cube 40GX. It's an AMAZING AMP!

Unfortunately, It's impossible to buy the Roland GA-FC in Argentina, so I decided to make one.

Do you success??

Regards
Title: Re: Building a ga-fc foot controller
Post by: PRR on August 02, 2016, 05:25:00 PM
Welcome!

> Do you success??

I have not even seen a picture of this GA-FC.

What we really need is a Schematic, of the GA or of an amp which uses it.

The Cube 40GX manual implies that basic functions (clean, lead, solo) can be switched by shorting Tip or Ring to ground. Has anybody even tried that??

The full GA can apparently switch those plus EFX, Delay, Reverb. To do this on 3 conductors, it must be sending coded pulses. There must be real "smarts" inside the GA. This would not be a trivial reverse-engineering.
Title: Re: Building a ga-fc foot controller
Post by: giglesias on August 02, 2016, 05:56:48 PM
Hi PRR!

(http://bb.steelguitarforum.com/userpix1403/5683_IMG_2398resized_1.jpg)

This is the Image.
I was looking a lot for a Schematig but it's impossible to reach on internet. I believe that coded pulses are used, but I dont know how it's works.
Althou , the side panel have 2 mono plugs for expresion pedals.Very complicated to understand how does it work thru a TRS cable.

Thanks for your help
Title: Re: Building a ga-fc foot controller
Post by: giglesias on August 04, 2016, 05:35:24 PM
can anyone help me?  :'(
Title: Re: Building a ga-fc foot controller
Post by: Pofper on August 16, 2016, 01:28:02 AM
hey, sorry for late reply, but I'm losing hope, since there's no support in the net, and I can't get my hands on an actual pedal so I can see the circuit!
Otherwise, the Clean/Lead Solo footswitch is fairly easy, and I have made one myself, I've provided the circuit image here in one of the replies, but it seems like something went wrong and the image is not showing anymore, I will try to make another one and upload it =)
Title: Re: Building a ga-fc foot controller
Post by: Pofper on August 16, 2016, 01:47:43 AM
Here is the circuit for the footswitsh :D
https://drive.google.com/file/d/0B01ggt8vJ3MwSEJTSnJuZ011d0E/view?usp=sharing
Title: Re: Building a ga-fc foot controller
Post by: Chops9012 on August 18, 2016, 04:44:00 AM
Thanks pofper, i am going to see if this works with my ga112, a superb amp if you ever see one going cheap.

Title: Re: Building a ga-fc foot controller
Post by: giglesias on September 15, 2016, 10:38:33 AM
Hi!

I've just bought one used in eBAY, it's in transit to Argentina. After receive i'll compare the total cost versus local cost, it's a half price.

And of course, I'll put some pictures, if I can open easyly. Then some genius in this forum can make revesal-engineering  ;)

Regards!
Title: Re: Building a ga-fc foot controller
Post by: potul on September 16, 2016, 03:57:54 AM
Looking at what the footswitch does, you can be 99% sure it has some intelligence, most probably a digital system. No easy to clone unless you debug all the communication between the FW and the amp and recreate that using some microcontroller (arduino, pic, etc...)
Title: Re: Building a ga-fc foot controller
Post by: CarlosPrex on December 17, 2024, 03:19:14 PM
Quote from: Pofper on August 16, 2016, 01:47:43 AMHere is the circuit for the footswitsh :D
https://drive.google.com/file/d/0B01ggt8vJ3MwSEJTSnJuZ011d0E/view?usp=sharing

Could you please share the circuit schematic again please?