ELANTRIC - Roland US-20 "Magic Box Mod"- I/O External FX Loop, and Remote S1/S2

Started by Rhcole, April 14, 2011, 04:27:16 PM

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zapantalambda

****UPDATE****
so guys after almost 3 months, i have managed to score myself a Roland US-20 Line Selector pedal.
next thing is, how to contact @elantric so i can have my unit modified?
or who mods US-20 in australia? pls advice


Fusion

Try hitting Elantric's PM on this site, he probably does not get around to looking at everything. I think he still does the mod.
"Long ago in days of old when magic filled the air..."

Elantric

Sadly the cost of round trip shipping from Oz to California to Oz really creates an undesirable high cost which makes other GK 13 guitar FX loop options from third parties more cost effective.

All are listed here

https://www.vguitarforums.com/smf/index.php?board=174.0

Primova Sound

DR Wayne Joness

RMC Fanout box


zapantalambda

Quote from: Elantric on March 24, 2015, 09:21:34 PM
Sadly the cost of round trip shipping from Oz to California to Oz really creates an undesirable high cost which makes other GK 13 guitar FX loop options from third parties more cost effective.

All are listed here

https://www.vguitarforums.com/smf/index.php?board=174.0

Primova Sound

DR Wayne Joness

RMC Fanout box

i see & understand @Elantric. question though. since the roundtrip cost is undesirable and not the best option for me who is based down under, would you be happy to share to me the diagram on how to tweak the US-20 so that I'll just try my best to do it myself? or do you have a spare modded US-20 that I can buy from you? just bcos Im desperate to complete my analog + GR55 combined pedal setup. I reck'n thats the best option I got, isn't it?

stevelukather

Hi ! .. Same problem here !. I live in Chile (South America).

It's is possible share the diagram or sell complete and moded unit ?

Thanks !

KeldAmpworks

Hi,

If you can't use Elantric's mod for shipping reasons, maybe you might be interested in an FX loop PCB i made. I've got one going spare, it should be cheap(ish) to ship just the PCB to Chile (I'm in the UK). It doesn't do the S1/S2 breakout or US20 function though, you'd need Elantric's mod for that.

http://ampworks.co.uk/experiments/gr55-gk-bobbib7/

Hope you don't mind me suggesting this Elantric, I don't want to steal your business. :)

Elantric

No problem - my "- Roland US-20 "Magic Box Mod"s are not earning enough   -after 4 years, I think I've done 10 total.

FWIW - its really a basic mod, and the US 20 schematics have been posted for a while
https://www.vguitarforums.com/smf/index.php?topic=480.msg1909#msg1909


- I guess you just need to know where in the circuit to cut and splice the new jacks

or buy a PrimovaSound GKFX-21 for the Guitar Input
https://www.vguitarforums.com/smf/index.php?topic=15681.0


or add a Guitar Input to your GR-55


Elantric

PDF Instructions for Roland US-20 "Magic Box Mod"-  I/O External FX Loop, and Remote S1/S2

(see attached)

Ron G

I love my GP-10 but would like to have an effects loop.  I'll admit to not understanding of lot the posts here.  I did purchase a GKFX-21 from CodeSmart that I use to alternate between my GK equipped guitar and a mandolin plugged into the guitar in on the GKFX-21.  The mandolin of course doesn't require any effects pedals but I would love the option to run a couple pedals between my guitar and the GP-10.  I don't know how to do this and use the 13 pin GK cable.  I use time based pedals after the GP-10 and it works beautifully (I primarily run direct to a DI and to FOH).

Am I missing a way to incorporate a loop into this set up?

Thanks!

KeldAmpworks

I'm not sure about the GKFX-21, but with my (very affordable, but badly named!) BreakOutBreakInBox http://ampworks.co.uk/experiments/gr55-gk-bobbib7/ you'd do this...

GK guitar into the BreakOutBreakInBox GK input,
connect the BreakOutBreakInBox jack output to the jack input on your drive pedal,
the drive pedal output to the BreakOutBreakInBox input jack
the BreakOutBreakInBox GK OUT to your GP10 GK in.

You could probably do something similar with the GKFX-21 unit, but you'd need a second separate switcher box to do what you're after if you keep your mandolin in the rig.

Shameless Plug alert...
I've got one board left and I'll include a connection drawing detailing what you want if you buy it! I won't be building any more at this time, because it looks like Primova has it covered!

Elantric

These "FX Loop " options ( Modified US-20 or GFX21 or the Buffer  / FX Loop box from DR Wayne Joness) function on the normal 1/4" pickup signal path only.

The hex pickup is 6 signals  - and if you seek to place FX on that signal path  - there is the Spicetone 6APPEAL, which provides a hex Fuzz and many other options

more here:

Spicetone 6APPEAL
https://www.vguitarforums.com/smf/index.php?topic=12104.0


And check out the RMC Fan Out Box
https://www.vguitarforums.com/smf/index.php?topic=2062.0

More GP-10 FX loop tricks
https://www.vguitarforums.com/smf/index.php?topic=17552.msg125267#msg125267

Ron G

Thanks for the information and links.  At this point I'm not sure the extra real estate required on my pedal board for these items would be worthwhile.  I'm content with  with my sound, just suffer from the guitarist next best thing disorder.

Great info found as usual on this forum!

Ron

Elantric

Quoteheavyweather wrote>
Hi,

Before selling the GI-20, I wanted to A/B it with the GR-55 (using the US-20, of course) to see if it had better tracking - I didn't want to sell the GI-20 if it was inherently better - and right away I encountered the issues of MIDI triggering external Synths differently
As you've described in many of your posts with the US-20, it doesn't AB/Y switch control between the GI-20 & the GR-55 -and both GI-20 & GR-55 MIDI out's are live all of the time).

I understand your posts where you say the US-20 doesn't actually switch all 13-pins, but rather, passes a signal to tell the "off" unit to take its volume to zero.  The GI-20 doesn't have this issue, but ONLY if the GI-20 is plugged into Ch. A.  Per your posts, I went into the SYSTEM settings and ensured that the GK-VOL setting = PATCH VOLUME, but it didn't correct the issue with either unit.  Also, with the VG-99, when I selected BOTH, the COSM output drops significantly.  That doesn't happen when I take the US-20 out of the circuit.

Essentially the US-20 is a Y cable for all 6 audio signals from the source GK guitar and the two destination GK processors.

As we know, the resulting user experience for all aspects of each GK processor is directly correlated to the GK String Sensitivity Level

The measured GK String sensitivity (as monitored on the provided Meter on the GK processor ) WILL be different when physically connecting the US-20 A/B/Y Switcher and two GK processors due to insertion loss on the 6 String audio channels

Most users find they may need to raise the string sensitivity a bit higher, to compensate for the added signal load on the String audio channels when the US-20 A/B/Y Switcher and two GK processors are powered ON  - as typical for live performance use.
   

Inserting the US-20 into the GK 13 pin signal path and connecting both target GK units