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

Started by hugowester, June 22, 2008, 09:10:45 AM

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shawnb

#25
I have the same setup, US20=>VG99 & GR55.   No hum problem. 
Address the process rather than the outcome.  Then, the outcome becomes more likely.   - Fripp

musicman65

Thanks ShawnB. I suspected others were using the US20 without issues.

As to the question of my exact setup:

RRStrat to US20 to VG99 and GR55. Both VG and GR are connected to my studio mixer with Left and Right 1/4" cables. No USB or MIDI to outboard gear. Both VG and GR power supplies are on the same power strip.

I am going to plug in Headphones to the VG and the GR directly while they are not connected to the mixer to see if the ground loop is in the audio circuit.

I'm leaning towards a bad US20. We'll see. Thanks to all who have responded.

Musicman65


kenact

Quote from:  musicman65 on March 01, 2011, 11:07:33 AM
RRStrat to US20 to VG99 and GR55. Both VG and GR are connected to my studio mixer with Left and Right 1/4" cables. No USB or MIDI to outboard gear. Both VG and GR power supplies are on the same power strip.

If all your cables are grounded, you might try using a pair on one of the units with the grounds lifted, just to ensure there's no ground loop.
Godin Session & Montreal FTP, LGXT, LGX SA, Redline, ACS, A12, A11, A10, A4
Danoblaster Baritone w/GK-3
Gretsch Nashville, Viking
Fender Strats
Fret King Supermatic
Larrivee DV03RE
Parker Midi Fly
Seagull, S&P 12
VOX Phantom XII
GR-55, 33, 30, 20, GI-20, RC-50, US-20, VG-99, VP-7
Sentient 6
Cyr 7

Elantric

QuoteBoth VG and GR are connected to my studio mixer with Left and Right 1/4" cables.

This might be the problem

If you have balanced 1/4" TRS inputs on your mixer,
Use the VG-99 XLR Sub outputs - these are  balanced

Use XLR female to 1/4" TRS balanced audio cables to connect your VG-99 to your mixer.

if hum persists, then Lift / float  the shield connection on these XLR female to 1/4" TRS balanced audio cables between the VG-99 Sub Outs to the Mixer Balanced Line inputs.

Brent Flash

You may know this already but just in case I would like to add some suggestions to this thread.

Ground loops can really be hard to figure out. Anything that is plugged into AC and then connected (audio cable, USB, MIDI, 13 pin cable, video cable, etc.) to another device that is plugged into AC has the potential to create a ground loop. And as other devices that are added to the connection that give potential ground paths increase the chances of getting a ground loop increase. It usually is caused by the device that you least suspect. Like USB or the mixer or something plugged into the mixer that is not part of your guitar rig.

One way to trouble shoot is to start unplugging audio cables, USB cables, while listening for the hum to go away. Also PFL channels on the mixer to see if it is coming in from one unit or both. For example just the VG or GR or both. Does you guitar have a GK3 and if so do you have the 1/4" cable from guitar out connected to the GK guitar in. Is there a guitar out of the VG connected to an amp?

If you have narrowed it down to the VG try an isolation transformer between the audio out and the mixer. Also if your VG is connected with XLR have you tried the ground lift on it.

If headphone outs are clean on both units more than likely it is the connection to the mixer. Use the XLR on the VG and run the GR into DIs that have ground lifts.

I guess it is possible that the US20 is defective but just because it starts when you use it does not mean that is the cause if you know what I mean?
Good luck in your quest. Let us know what you find.

djidoe

#30
Hi guys, will the GK S1 and S2 switches will work if I use a US-20 to send signals to a VG-99 and a GR-55. Also if I'm using the DIY "Poor man US-20" http://www.xs4all.nl/~pekveren/us20/ will thoses S1 and S2 switches are supposed to work ? Because my brother made me this DIY project and the S1 and S2 aren't working when I plug the pedal in front of my 2 units. He want to know if he just made an error or if those switches are simnply disabled in the DIY project plan.

Thanx

Elantric

#31
QuoteHi guys, will the GK S1 and S2 switches will work if I use a US-20 to send signals to a VG-99 and a GR-55.

Yes they do work with a factory US-20.

On the GR-55 the S1 & S2 should manipulate the GR-55 Bank Up / Down functions.

And the HomeBrew US-20 schematic should work too


Check the wiring of IC1 - since Mr Pekveren when he poorly copied the version from Harold Milz forgot to include the CD4066 IC pin numbers and the IC1 Power connections on that US-20 schematic!
http://www.muc.de/~hm/music/us-20/





Check the wiring of IC1 - the CD4066 Quad Analog Switch.

A better set of plans with complete details is here:
https://www.vguitarforums.com/smf/index.php?topic=480.0



klunk

#32
Has anyone tried to make a three way 13 pin splitter using two US-20's  (will it work?) and/or is anyone interested in getting rid of a GKP-4?

paults

Someone offers a three way splitter, with on/off buttons, I think.  Try a site search.

Elantric

#34
Look here:

VGuitar Forums > For Sale > GK Pickups / Tools / Accessories
https://www.vguitarforums.com/smf/index.php?board=174.0

klunk

Hi, thanks for the replies. sorry for originally posting in the vg99 section--i wasnt paying attention!  Awhile back i ordered an SGUS (freaking exspensive, by the way): it took two months to get here, with alot of "we are not sure where it is but we sent it" response to my polite email inquiries which i didnt start sending until a month had gone by (shipping was estimated at 25 days).  When it finally did arrive, it was D.O.A. (which to them was impossible/unbelievable)...i sent it back (it is made in europe, shipped out of germany, so shipping wasnt cheap). They said they would send me a new one if i sent the old one back. I replied i prefered a full refund. They said they would refund my return shipping if the unit was faulty...they never refunded my shipping. i guess it magically started working once they got it back!...i dont think i will try buying another one from over seas. So, Has anyone tried chaining two us-20's or is there a reason it wont work...does anyone want to get rid of a gkp-4? or get rid of a fully functioning SGUS from the united states? Thank for any help.

ericar123

I have been doing research on this subject and have come up with this. Buy a manual rotary switch like the Manhattan data transfer switch.
They are a simple rotary switch with around 30 poles on them. buy 5 - 13 pin DIN female jacks and replace the jacks on the data switch. Do some soldering and you have a simple cheap switch that can be used either as a 1 into 4 or 4 into 1 switch. Depending on how you wired it you could even customize the configuration into something like GK into a,b or c and d together. You should be able to do this for around 50 clams. Also if you wanted to get 2 switches you could have 4 switchable GKs going into 4 switchable Roland units. The ultimate rig! The only down side is that these
switches are not foot switches. It doesn't matter to the basement musician like me but maybe to the live musician.

Eric


ericar123

Here are some links for the switches. the jacks are harder to come by.

http://www.cablesnmor.com/manual-switch-box.aspx

https://www.cablemax.com/150644.html

Use the DB15 or the DB25 I think. They have enough wires for the 13 pins.

http://connector.telecomnet.com.tw/DS-101.htm

You could use epoxy like JB Weld to fix the jacks to the case.

Elantric

#38
For multiple Hex Guitars into one GK13 processor, many have adapted these type VGA Selector Box's for this purpose

For less than the cost of a 15pole, 4 way rotary switch, you can buy a Asian VGA selector box .

Then build  DIN 13pin to HD15 adapter cables.

http://www.amazon.com/Ports-VGA-Switch-Selector-Monitor/dp/B003DTZQFY


http://www.electronicplus.com/content/ProductPage.asp?maincat=cs&subcat=csb

klunk

Thanks for your inputs: Interesting idea with the computer junction box thing; is anyone out there using a homemade 13 pin splitter?  From the looks of the us-20's guts (resistors, capacitors, an IC chip and some things labed  "Q1,Q2,Qetc.")...it seems abit more comlex than simple wiring connectors/cables to a switch box. But i dont even solder, so good chance of it taking me forever and still not work!  I'd have to hire someone to build it and i am sure the end cost would equal or near-equal a roland factory built product...since i would prefer a 4way switch, the question regarding the chaining of us20's is mostly curiosity, partly a "plan B" if it will work and i cant find a gkp4, and partly an obsession to get an answer to a long unanswered question ( i began my inquiries on this matter about a year ago). It seems no one on the midi-guitar forum, this forum, and the gr30 forum has ever tried to chain the us-20's! I dont even know anyone in my town that has a us-20 that i can borrow!

ericar123

It's funny how forum topics get so off topic. I am sure that two us20s would work. The only thing a US20 won't do is work in reverse. You can only split 1 GK into many outputs. If you had 3 US20s then you would have 4 outputs and so on. Each additional US20 would add 1 more output. If I were you, I would ask some friends. Someone you know must have a little experience soldering. The computer switch thing will work for sure and is a cheaper way out. Good luck.

A2theT

I still have a similar issue which I posted in another thread but mine is a light crackle.  Turning up noise gate on vg-99 resolves it but it is impeding the overall signal.
I wish I could solve this.  My setup is pretty basic.  VG-99, GR-55, US-20.  Both VG and GR outputs are sent to my Behringer Powered Keyboard Monitors.  If i disconnected the GR  1/4" outs or vg 1/4" outs the crackling stops.  Doesn't matter which one I disconnect but they both can't be going at the same time without crackle.  I have a balanced in on these speakers and have also tried that to no avail.  I also tried the ground lift switch on back of VG-99 but it still happens.  Wish I could solve this one.  I have replaced every possible cable. I even tried using the headphone outs of both vg and gr and sending them to my powered speakers but same result...  Must be a loop somewhere.  jeeshhhhhhhhh! ??? ??? ??? ??? ??? ???
HEAVY on the METAL
Axe-Fx II, Roland VG-99 + FC-300, Roland GR-55, Digitech Jamman Stereo, Ibanez/ESP/Jackson Guitars

Brent Flash

Quote from: A to the T on May 03, 2011, 06:37:50 PM
I still have a similar issue which I posted in another thread but mine is a light crackle.  Turning up noise gate on vg-99 resolves it but it is impeding the overall signal.
I wish I could solve this.  My setup is pretty basic.  VG-99, GR-55, US-20.  Both VG and GR outputs are sent to my Behringer Powered Keyboard Monitors.  If i disconnected the GR  1/4" outs or vg 1/4" outs the crackling stops.  Doesn't matter which one I disconnect but they both can't be going at the same time without crackle.  I have a balanced in on these speakers and have also tried that to no avail.  I also tried the ground lift switch on back of VG-99 but it still happens.  Wish I could solve this one.  I have replaced every possible cable. I even tried using the headphone outs of both vg and gr and sending them to my powered speakers but same result...  Must be a loop somewhere.  jeeshhhhhhhhh! ??? ??? ??? ??? ??? ???
Plug the VG's AC into same place the GR is plugged in or experiment where they are plugged in. It could be anything that is connected to AC and audio.

Elantric

#43
QuoteBoth VG and GR outputs are sent to my Behringer Powered Keyboard Monitors.  If i disconnected the GR  1/4" outs or vg 1/4" outs the crackling stops.


The noise you describe is caused by switching power supplies in all your gear, and a ground loop in the Audio path.
True  - no 60 Hz Hum is heard, instead you have pops and crackling - yes this noise is due to a ground loop.

Solve this problem by breaking the loop - by Inserting a Passive DI box (not active ) between the 1/4" Outputs of either the GR-55 or the VG-99 and the target  Behringer Powered Keyboard Monitors.


DO not use an Active DI box - these do not provide the galvanic isolation required to break the ground loop.
This works as a Passive DI box:

http://www.amazon.com/ART-Direct-Professional-Passive-Box/dp/B0009GYIL2

A2theT

Quote from: Brent Flash on May 03, 2011, 06:52:56 PM
Plug the VG's AC into same place the GR is plugged in or experiment where they are plugged in. It could be anything that is connected to AC and audio.

Everything is plugged into my power conditioner.  I've now split everything into different outlets in my house but same issue.
HEAVY on the METAL
Axe-Fx II, Roland VG-99 + FC-300, Roland GR-55, Digitech Jamman Stereo, Ibanez/ESP/Jackson Guitars

A2theT

Quote from:  Elantric on May 03, 2011, 10:29:00 PM

The noise you describe is caused by switching power supplies in all your gear, and a ground loop in the Audio path.
True  - no 60 Hz Hum is heard, instead you have pops and crackling - yes this noise is due to a ground loop.

Solve this problem by breaking the loop - by Inserting a Passive DI box (not active ) between the 1/4" Outputs of either the GR-55 or the VG-99 and the target  Behringer Powered Keyboard Monitors.


DO not use an Active DI box - these do not provide the galvanic isolation required to break the ground loop.
This works as a Passive DI box:

Thanks Elantric, will try this next.  In 25years of playing guitar and jamming and mics and PA's etc I've never experienced this..
HEAVY on the METAL
Axe-Fx II, Roland VG-99 + FC-300, Roland GR-55, Digitech Jamman Stereo, Ibanez/ESP/Jackson Guitars

Brent Flash

Quote from: A to the T on May 04, 2011, 05:02:53 PM
Everything is plugged into my power conditioner.  I've now split everything into different outlets in my house but same issue.
Those things can be hard to track down. I will never forget back in the analog days when we had racks of FX units and racks of Compressors/limiters/gates all hooked to a Yamaha 4K with insert cables and I had a ground loop. All the racks and the board were hooked to the same leg of the distro which should have given us a loop free setup. After lifting this ground and lifting that ground, nothing was working, I decided to plug the FX rack into the AC power condition in the Compressor/limiter/gate rack. The hum went away. So just for kicks I plugged the Compressor rack into the FX rack, hum was back. The only way it would work was the FX rack plugged into the Compressor rack. And this only happened at one venue in Galveston, Texas and no others.

Isolation transformers are usually the best fix, but sometimes there is no way to isolate the audio like in the situation I had in Galveston. I would have had to have about 24 of them to isolate all the inserts.

Good luck with it!

Elantric

#47
QuoteThanks Elantric, will try this next.  In 25years of playing guitar and jamming and mics and PA's etc I've never experienced this..


Switching power supply noise is a relatively new phenomena with unbalanced Guitar gear, due to the 2005 era EPA legislation mandating "Green" external power supplies must replace all inefficient DC linear power supplies.

Even pre 2005  Roland  / Boss ADA and PSA supplies (for Boss pedals )have been redesigned and replaced by new versions

http://www.bossus.com/gear/productdetails.php?ProductId=911&ParentId=253


More here:
http://en.wikipedia.org/wiki/Switched-mode_power_supply


http://www.energy.ca.gov/papers/2005-03-03_WILSON.PDF









A2theT

I'm going to the store tomorrow to buy the ART DualZDirect box and see how that goes.  I was looking at the HumX by ebtech but man, $71 !
HEAVY on the METAL
Axe-Fx II, Roland VG-99 + FC-300, Roland GR-55, Digitech Jamman Stereo, Ibanez/ESP/Jackson Guitars

klunk

I will definitley look into the computer switchbox idea because i am curious to see if it will work. maybe, if nothing else, it'll be the impetus for me finally learning how to competently solder. thanks to all for your responses.