GR-55 - GK3 guitar out not working

Started by Elantric, February 16, 2011, 10:13:09 AM

Previous topic - Next topic

0 Members and 2 Guests are viewing this topic.

BobTheDog

The hiss is there when nothing is connected to the GR-55 though!

Elantric

#26
True!
The guitar signal must pass through numerous additional buffers, a Normal  / COSM guitar mix stage and a programmable gain stage - all internal to the GR-55 which feed the GR-55's "Guitar Out" jack.

You are never going to get "True Bypass" with a stock GR-55.

BobTheDog

Fair enough.

I would be interested in a low noise mod, I usually have the eq up on the high end which really brings out the hiss :(

Jim Williams

I don't know if this will help, but there is a setting for your normal guitars output in the GK settings. Try playing with that as for myself I have not noticed that problem with my GR-55. I tried sending my guitar out to my SGX 2000 and it worked good but after using Roland gear for so long I found that 80's relic to sound bad... No fault of the GR-55.
Skype: (upon Request)

Everything from modeling to the real deal, my house looks like a music store.

Elantric

The bulk of GR-55 Guitar Out hiss problems will arise when you feed into a high gain tube Amp, or a typical pedal board with overdrive / distortion  pedals. It can become quite noisy if the gain is set too high on anything the GR-55 Guitar Out jack is feeding. 

Will Robinson

Quote from:  Elantric on April 14, 2011, 12:10:54 PM
The bulk of GR-55 Guitar Out hiss problems will arise when you feed into a high gain tube Amp, or a typical pedal board with overdrive / distortion  pedals. It can become quite noisy if the gain is set too high on anything the GR-55 Guitar Out jack is feeding.
So I can expect unavoidable annoying hiss if I use the Gr-55 to model a guitar tuned down and sent directly to a Mesa MarkV crunch or lead channel without using any of the GR-55 amp sims or effects?
I was hoping to use it for synth sounds sent to FRFR and guitar sounds on a separate output (no Roland amp or effect modelling) sent to an AxeFx or Mesa MarkV.

Elantric

I would enjoy a report of your observations with the GR-55 Guitar Output feeding your Mesa MarkV.

If there is too much hiss, there may yet be a modification to the GR-55's internal circuit to minimize hiss and  noise.

I have a Bogner Alchemist here, and I will explore if I have similar noise problems and perhaps  make low noise mods to my GR-55.  If I'm successful, I'll report back. 

paults

If you maximize the amount Normal and model signal within the 55, you can lower the output level, and that will lower the relative level of the hiss.   

If it is still too noisy, use a noise gate, set low enough to just gate the hiss. There would be no hiss between notes, and it should be masked by the guitar signal while you are playing.

I can understand someone saying they don't feel like they should need one, but, they are pretty much a fact of life with complicated high gain rigs.  If you were running a VG-99 into the front end of your amp, you would be using one with it, too.

If you don't want to gate your normal guitar signal when it is going to your normal amp, there are options as simple as sending that signal through a separate cable, or using a breakout box, or as complicated as a MIDI programmable effects loops controller that re-routes the normal guitar and modeled guitar for each patch.

MrSparkle

#33
I did notice the hiss when the USB cable was connected.. Was using the GR-55's midi control and sending 1 synth out and 1 guitar out into my Apogee interface (so my Duet was outputting to monitors)... There was so much hiss I couldn't record (you could hear the hiss compete w/ the recorded audio volume!) At first I was really confused until realizing it had to be the USB cable.

My VG-8 had major hum problems from all outputs, so I got the Hum X jack which has been amazing for a bunch of my units... $60, but really worth it as it silences most ground loop hums. I didn't try yet with the 55, but I'm not sure if that would fix the 55's problem... I'll check it out.

Elantric

#34
QuoteI did notice the hiss when the USB cable was connected..


This is due to a mix of  ground loops and the switching power supplies employed on all your devices , the anomalous noise manifests as Hiss and not the typical Hum.

If you are using a laptop,  - the hiss will go away if you run the laptop on its internal battery power.


Another solution is a USB Galvanic isolator

====

Every Computer Musician in a live situation will eventually run into this problem:

"Why does my new Computer based Guitar processing system  make so much noise when i connect my Audio Interface to my Amplifier or the House PA?"

The problem is typically traced to a Ground Loop problem between the Computer and the USB  / Firewire Audio Interface.

This thread below is a good read for understanding the problem and finding a solution.

http://electro-music.com/forum/topic-16104.html

And here is product specifically designed to solve USB 2.0 Audio Ground Loop issues
http://www.olimex.com/dev/usb-iso.html

Apple has a reference doc on this issue here:

http://support.apple.com/kb/HT2743




And this link below is good reading to understand the problems of Ground Loops in the Audio Processing path
http://www.epanorama.net/documents/groundloop/home_solving.html

sheguitarplayer

Quote from:  BobTheDog on April 14, 2011, 11:10:57 AM
Fair enough.

I would be interested in a low noise mod, I usually have the eq up on the high end which really brings out the hiss :(
I too would be interested in a low noise mod.
I would love to be able to run from the guitar via GR55 (for mag pickups as well as for cosm models and alt. tunings) into the Marshall afd, which is as I have mentioned a single channel high gain amp, compounded by a built in power amp scaling system.

Elantric

Disconnect the GR-55's USB cable will lower the Hiss dramatically.

btroppma

Hey just wanted to mention on the subject of using the guitar out jack, I am using it to send my guitar signal to TC Helicon VoiceLive 2 vocal processor, and it works great. For this purpose, a clean dry guitar signal is preferable for the harmony/chord detection that the VL2 does.  I'm running all the signals (Gr-55 mono out, vocal, and the thru guitar out of the VL2) into a Bose L1 model II (with T1).  Having a ton of fun with it, plus they look so good sitting beside each other....:)
Bob

ddlooping

Welcome to the forum, Bob, and thanks for the info, it is indeed a great application for the GR-55 "Guitar out". :)
Diaz Guitars (work in progress)

Elantric

#39
Thats a great concept!

It would also work with the Digitech Vocalist Pro units too, and maintain proper auto Vocal harmony chord relationships when playing COSM Alt tunings. 

gumtown

I have been quite interested in either the TC Helicon Harmony-G XT or the Harmony-M to run with my GR-55,
the Harmony-G uses the audio signal (from the GR-55 guitar-out) http://www.tc-helicon.com/products/voicetone-harmony-g-xt/
and the Harmony-M uses midi from the GR-55 midi out. http://www.tc-helicon.com/products/voicetone-harmony-m/
Anyone have thoughts on which would work best?

I think my hopes to use one may be dashed, because I use my GR-55 with bass, and the Vocal Harmonist effects require a root note and a major or minor 3rd chord.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

nelcatjar

It actually makes sense to only have the dry pu signal going through the output jack.  That way the signal can be sent to another effects processor.   Since the modeled and COSM are already going through the regular output jack, why would I want to send that signal again out through another jack.

I could see a switch to turn on/off what goes through the guitar out jack.  Looks like a documentatin faux pas.

Q: What's the difference between a musician and a large pizza?
A:  A large pizza can feed a family of 4.

Brian Moore i88.13, Godin xtSA, GR-55, Boss ME-70.

ddlooping

Quote from: gumtown on April 28, 2011, 06:38:59 PM
I have been quite interested in either the TC Helicon Harmony-G XT or the Harmony-M to run with my GR-55,
the Harmony-G uses the audio signal (from the GR-55 guitar-out) http://www.tc-helicon.com/products/voicetone-harmony-g-xt/
and the Harmony-M uses midi from the GR-55 midi out. http://www.tc-helicon.com/products/voicetone-harmony-m/

I'm also looking into both of them. :)
I can't see any mention of a "pitch correction" update for the Harmony-M though. :/
Diaz Guitars (work in progress)

or8ital

I just started using the Guitar out on my GR-55 into my AXE FX II. The hiss on high gain patches makes using the guitar modeling in the GR-55 impossible. Has anyone found a workaround for this yet?

Elantric

#44
Tweak the GR-55's GK COSM Guitar  Noise Suppressor :


or8ital

Quote from:  Elantric on July 27, 2011, 03:53:00 PM
Tweak the GR-55's GK COSM Guitar  Noise Suppressor :



hmm just tried that. It doesn't seem to have any effect on it.

or8ital

Quote from:  or8ital on July 27, 2011, 04:00:02 PM

hmm just tried that. It doesn't seem to have any effect on it.

Did just try adding a gate on the AXE FX. It does clean it up but I can tell its there. Sure wish I could figure out what is causing that. Kind of weird for a mostly digital signal.

It weird that the NS on the GR-55 did nothing but the gate on the AXE FX did.

or8ital


Elantric

#48
QuoteDoes the vg-99 do this?
No


The VG-99's Guitar out has a direct connection from the Guitar In jack on the GK-3. The GK-3 has a op amp buffer  - but thats the only active element in the signal path.

The GR-55 is very different.

The hiss problem in the GR-55's Guitar Out jack is due to the unique COSM Guitar Output option and "Normal" or  "COSM"  guitar signal selection switching circuitry. For COSM guitar feeding the GR-55 Guitar Out, there is a DSP and a DAC and a basic low budget analog opamp circuit feeding the GR-55 Guitar output jack -  all the time.

Also the  GR-55's Guitar Out jack  "hiss" is mostly apparent when you feed a hi gain guitar amp on the Lead boost channel.

If you are a new age acoustic type or clean jazz / surf / rockabilly type - you will probably not find any problems with the GR-55 Guitar output jack.

But if you play Blues / Rock /Metal - the hiss when feeding the Lead channel on a typical Guitar amp will be a big problem.


The GR-55 "Work-around" for the Guitar Out jack's "hiss"  - use a separate 1/4" cable from your guitar's normal output jack, and feed your normal guitar pedal board / Amp.



   

DF400

#49
I use my GR-55 regularly for gigging. One os the great features is that I can cross-fade from synth (PCM) to magnetic guitar output using the expression pedal. Unfortunately, I was getting terrible feedback. I then noticed that when I lowered the Normal Pickup level on the menu, the output also lowered - but the signal remained "processed" by the GR-55.

My question is:
Is there a way to route my guitar signal through the GR-55 without altering (or processing) the signal, then feed my amp from the guitar out? The obvious adjustment would have been to turn off the amp feature, however, this seems to only affect the guitar modeling feature.