Roland US-20 GK A/B/Y Switcher / Router pedal

[hugowester]

hi folks,
i have the following problem
with some patches i´ve downloaded from the library,when i switch the US 20 from VG 99 sound to synth/Axon)the VG doesnt shut up,it keeps sounding.For example,the Etherige patch switches OK,but the Walsh not.Obviously,it has to do with some setting in the patch,but i hav´nt discovered ir yet.¿any clue?
thanks
hugo

[ggomez1]

Same problem here but haven't been able to fix, I also have the issue of the VG99 still sounding when the GK3 selector is set to the regular pickup in some patches only. I'll let you know if I can come out with the fix.

[Brent Flash]

I also have the issue of the VG99 still sounding when the GK3 selector is set to the regular pickup in some patches only. I'll let you know if I can come out with the fix.

About the GK-3's Select Switches
As the VG-99 allows you to set the balance between the COSM guitar
and the normal guitar volume in each individual patch, we
recommend that MIX be the basic function used for the select switch.
Also note that if a parameter other than volume is assigned as the
GK volume control function, the GK-3's select switch will stop
functioning normally.

[TGermon]

Hi all,

This is another US-20 problem but I guess it can be put under that same topic.
Just got my US-2O brand new. When I use it with only the VG99 or the GR20, it works just fine. But if I plug both VG99 and GR20, I get a huge hum and buzz from the VG99 (and not at all from the GR20) on top of the sound. No matter which cables I use (short GK cables provided with US-20 or other GK cables, except GK10) or A/B output combination for both machines, I still get that buzz. Clean or acoustic sounds with a lower output volume won't buzz as much as saturated ones but they still buzz enough to make that setup unsable on stage.
Ground lift on the VG99 doesn't help either.

Anyone got the case? Did I simply got a failing unit? I guess I could use some help from knowledgeable fellow users

Thanks,

Thierry

[Brent Flash]

Hi all,

This is another US-20 problem but I guess it can be put under that same topic.
Just got my US-2O brand new. When I use it with only the VG99 or the GR20, it works just fine. But if I plug both VG99 and GR20, I get a huge hum and buzz from the VG99 (and not at all from the GR20) on top of the sound. No matter which cables I use (short GK cables provided with US-20 or other GK cables, except GK10) or A/B output combination for both machines, I still get that buzz. Clean or acoustic sounds with a lower output volume won't buzz as much as saturated ones but they still buzz enough to make that setup unsable on stage.
Ground lift on the VG99 doesn't help either.

Anyone got the case? Did I simply got a failing unit? I guess I could use some help from knowledgeable fellow users

Thanks,

Thierry

Do you have the regular guitar pickups (guitar cable from guitar to GK-3 guitar input) plugged into the GK?

[TGermon]

Yes, but when I unplug that cable, the buzz remains.
When I select the regular pickups with the GK-3 switch, the buzz disappears, though I'm still using the VG99 patch through those PU, except for the guitar modelisation. Doesn't that rule out the ground problem hypothesis I was thinking of in the 1st place? In that case, that would be an internal VG99 problem but no one else seems to have it, do they?

Do you have the regular guitar pickups (guitar cable from guitar to GK-3 guitar input) plugged into the GK?

[Nick]

The US20 has a built-in by design ground loop problem.

Take a piece of electrical tape or better yet, suitably
sized heat-shrink tubing (my solution) and completely
enclose the outside metal portion of the short GK cable
plug that connects to your GR20 input. Hum should disappear.
(the connector will no longer be able to be locked at that end)

For the technically interested, this problem is due to
the fact that Roland chose to ground the cable shields
at both the source and destination ends. The difference
in potential between the two connected units causes
AC current to flow through the shield inducing noise
into the low level signal lines.
The tape trick floats the desination end of one cable
shield, consequently removing the loop.

[Elantric]

There's a rumor this ground loop is date code specific on the US20

I wlll look inside my 2002 era US-20 , and post pics and check to see if mine has similar ground loop issue.


Schematics are here
https://www.vguitarforums.com/smf/index.php?action=dlattach;topic=480.0;attach=432;image

https://www.vguitarforums.com/smf/index.php/topic,480.0.html

[Nick]

If you have an Ohmmeter, just measure the resistance at the metal
shells from the end of one cable to the end of the other while
they are plugged into the US-20 Unit A & Unit B connectors.
If you measure a low resistance (~1 Ohm), the ground loop
problem exists.

[flyboy]

I had same Problem Gkp4-VG8-VG88-VG99.solved by Pluging a 1/4 inch plug into the guitar in of the VG8.I don't Have my guitar pluged into my GK2A

[acousticglue]

Used to use US20 with VG8ex and GR30-33 and never had hum issues so must be date issue.

[Elantric]

Read here:

https://www.vguitarforums.com/smf/index.php/topic,434.msg1902.html#msg1902

[rando]

Greetings.  Anyone else having this problem?  I have a Roland US 20 A/B box with an Axon MK 2 Guitar synth (13 pin) and Roland VG 99 (13 pin) running from my RC 300 pedal board and into my PC through the USB cable (comes with the VG) and I have soooo much distortion.
If I run JUST the VG 99 into the RC 300 through USB to PC, no problem.
I've run the VG in different modes, sysx etc. but the two don't appear to be compatable although both share a 13 pin connection.
Thoughts anyone?

Thanks

[johnnyurq]

Hello All,

Firstly I couldn't think where else to put this request so figured here was as good as any.

Also if this is against the house rules or in any way inappropriate please feel free to delete the thread.

As the title suggests I have need for preferably a Roland US-20 GK switching unit or failing that the parallel GK unit Roland GKP-4. I cannot find any on Ebay in the UK or another country that will ship to the UK.

The GKP-4 is discontinued so cannot be bought new and the Roland US-20 I can only find new at Thomann in Germany (again no US store that will ship to the UK) for £175 inc postage. Which seems expensive as they were much cheaper not too many months ago.

Bottom line is they are as rare as rocking horse sh*te on the second hand market.

If any forumite has either one of these two units they no longer have need of I would happily pay a fair price for one.

Failing that I will have to resign myself to getting the new one from Thomann.

Thanks for looking and here's hoping.

[klunk]

Hey johnny, i am having similar difficulties, although ebay has recently sold 2 gkp-4's and a few us-20's. I recently discovered the sgus-3 which acts as a 13 pin three way selector with individual on/off footswitches for all three channels (like the us-20 plus one) ! Now if i can just figure out how to buy it...

[UncleRage]

I realize that this is rather old post -- but I thought I'd drop a word in as I was actually looking in on both of these issues.

The hum is something I'm dealing with; but more disconcerting was the bleed through I was getting from the VG-99 on top of the GR-20.  Regardless of what I did (swapping cables, powering on and off, summon ancient blind idiot gods), I was getting the VG-99 stepping all over the GR-20. 

So, thinking it might be the GK-3, I switched guitars.  Same thing on two different GK-3's.

That's when it dawned on me... I had changed the setup of the GK-3 on the VG-99 to use the dial as a tone, not volume.  I switched back to volume and lo and behold, 'A' and 'B' were now separate paths. 

I'm still not sure I grok why switch of volume to tone on the GK-3 caused the VG-99 to step all over the GR-20, but it's something to keep in mind for anyone (like me) that's just starting to run through the halls and flipping every switch they find.  Actions do have consequences, who'd have thought?   

[ZenSonic]

I have a US 20 that I want to post for sale on EBay but only now have a GR55 to do a final test with. It always worked as intended but I realized I better check before selling it because I used both the VG and GR units simultaneously almost exclusively.. When I put the GR55 in the A input all lights function and sound is on or off contingent on the foot switch position. When I put the GR55 through the B input. No lights or functioning occurs. Must their be a VG/GR unit in input A for input B to function at all on a US20?

thanks

[paults]

Good news - the US-20 is powered by just one of the connected devices.  If you have just one, it will only power up connected to one side.  If you connect to just the other side, it doesn't work. 

[ZenSonic]

SWEEEEEEEEEEEEEEEEEEEEEEEEEET! thanks dude!

[musicman65]

Guys,

anyone know why a US-20 would create a really loud hum when both VG99 and GR55 are attached. The hum is gone when only one device is connected. I have moved cables around, swapped ports, made sure power supplies are on the same ground, etc. The unit is used so I'm wondering if its bad?

Perhaps Elantric or any other hardware gurus can chime in with their expertise in the internal workings of the US20?

Thanks,

musicman65

[727lawrence]

I had a similar issue with two amps and wasn't smart enough to figure it out. I picked up an EBTECH Hum Eliminator and that did what it claimed to do - eliminate the hum. If one of the gurus on here can't figure this out for you then I would go that route.

[musicman65]

Thanks. Good advice on the Ebtech. I believe that would fix it but I'm perplexed why I'd need it when others don't in the same application. It's a ground loop issue, most likely. Neither device has a lift or polarity switch....so why me?

musicman65

[musicman65]

bump!

so nobody else has a bad hum using a US-20 to interface to a VG99 and GR55 at the same time?

musicman65

[kenact]

The most likely cause would be a grounding problem.  Can you provide more detail on your exact set up?

[djidoe]

Is USB connected to 1 of the 2 units ? That may be the problem...