GR55 mod effect most often before the amp not after

Started by sixeight, March 12, 2014, 02:27:38 PM

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sixeight

OK, this is something that came up in another post, so it had to check it.

Pick an amp with mild distortion. Now switch the mod effect on and change the effect level of the mod effect. I found with most Mod effects (numbered 1 till 10) the amount of distortion on the amp changes, so the effect is connected before the amp.

Only the mod effects pan, delay, chorus and eq do not change the amount of distortion on the amp model - only the volume changes, but the amount of distortion stays the same - so these four effects are connected after the amp. As panning is the only true stereo effect, and the amps are mono this is also logical.

I guess Roland left it out of the documentation, because it only causes confusion. Most people do not hear the difference between an effect before or after the amp, so why bother.

Elantric

I agree! Thanks for tracking this down and documenting the realities of GR-55 signal flow.

vtgearhead

Thanks very much for quantifying that!  This forum is invaluable for getting accurate, thoughtful information. 

mojo thorne

That's indeed helpful... and a logical analysis!

I know that I read somewhere that Roland had confirmed that the effects would be after the amp, which never made any sense to me when it came to filters, distortion, etc.  I think that was before or right after the GR-55 was released, however.

Anyway, thanks for taking the time to investigate this and report your findings.  This actually opens up some new possibilities for me in terms of accounting for all of the effects that I want to use on some guitar patches!

Gaustu

#4
So coooool finding


Here is the real table of Mod effects placing according to my tests:


OD/DS   -before AMP
WAH      -before AMP
COMP     -before AMP
LIMITER  -before AMP
OCTAVE  -before AMP
PHASER   -before AMP
                        AMP -before FLANGER
TREMOLO -before AMP
                         AMP -before ROTARY
UNY-V     -before AMP
                         AMP -before  PAN
                         AMP -before  DELAY   (parallel)
                         AMP -before  CHORUS (parallel)
                         AMP -before  EQ
Parker PDF85 modified: Sustainiac, SD TB-4, Piezo Hexpander 13 pin out.
GR-55 mod with 13 din thru, 6 analog outputs D-Sub => Presonus FS Mobile  8 analog inputs.
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Elantric

#5
It's simply a DSP resource issue. Roland crammed as much as could be accomplished with one DSP to meet a price point.

Also today the GR-55 is $100 more than it was back in 2011. Folks forget that since it's introduction, the GR-55 has experienced two price fluctuations due to economic inflation.

aliensporebomb

That's right!  The price went UP.  Just imagine a VG-99 price today.  Pushing $1600 for the unit alone.  So the 55 is probably still a useful bargain in some quarters.

My music projects online at http://www.aliensporebomb.com/

GK Devices:  Roland VG-99, Boss GP-10, Boss SY-1000.

sixeight

#7
Fusion, most effects are placed before the amp, though the documentation suggests otherwise.

This is documented in another post: https://www.vguitarforums.com/smf/index.php?topic=10809.0

Fusion

After mulling this over and using my headphones creating some COSM stuff which I had not really gotten very far into since I have had the unit.
I was after the most intense articulate well EQ'd high gain amp I could create. Came to some interesting examples using all the high gain models and hovering around various boosts or ODs. If this discussion continues I will detail some of the better combinations I came across.
Sooooo....
I am indeed puzzled at the premise some of the MOD effect models might be in the signal path before the amp model. When I listen to the various models in the Distortion section seems like the gain structure is increasing upon the pedal model and not the amp. As the sound is not like an amp getting pushed. Seems like the Amp model is driving the gain or boost model. And this is not to say, it does not sound decent, it sounds rather amazing with the right combinations but I have my doubts some of these are before the amp model.
I would like to know what Roland has to say on the signal path as their documentation clearly places the MOD section after the AMP. If this is not the case can someone with some Roland contact savy find out for us from Roland what the skinny is?
Having been playing for more centuries than I care to count the sound I am hearing is not the amp increasing in gain structure but the amp driving the pedal model more. The reason one is not hearing the gain structure increase on the other MOD models is because they are not designed as gain structure circuits, just as with  std pedals one does not make a phaser, chorus, and such create "distortion" like a OD type pedal so you are not hearing that on the "testing".
We have to consider this is not really an "AMP" so it running into a pedal type model is not as unkosher as it would seem. The AMP thing is basically a circuit not unlike a pedal which is intended to mimic how an amp sounds. Surely Roland knows that various boosts, gains and distortions are made and sound better in front of an amp, but this is not really an "amp". I just have my doubts some of the MOD effects are before the AMP section in signal path, that is not what I am hearing in the gain structure. What do others think?

"Long ago in days of old when magic filled the air..."

Elantric

QuoteI would like to know what Roland has to say on the signal path as their documentation clearly places the MOD section after the AMP. If this is not the case can someone with some Roland contact savy find out for us from Roland what the skinny is?

Call them Monday

Roland Corporation U.S.
5100 S. Eastern Ave.
Los Angeles, CA 90040-2938
Customer Service Tel: (323) 890-3700


None are here to answer

Story of VGuitarForums
https://www.vguitarforums.com/smf/index.php?topic=7912.0

Fusion

Will do. Let's hope someone actually knows as many of the contacts one gets in various companies do not really know anything in depth of the circuit design. Maybe they can refer the question up the food chain. I think I know what the answer will be but for argument sake would be nice for Roland's input.
"Long ago in days of old when magic filled the air..."

vtgearhead

I'll fall over from shock if you are able to reach anyone able to give you a definitive answer based on first-hand knowledge of the software.  It's far more likely that you'll have someone read you back what they see in the manual.  Or, possibly, hide behind the old "..it's proprietary information" ploy.

But, good luck and let us know what they tell you?

Fusion

That would be my guess as well.
I know what I am hearing as I have a vast pedal config background and I am not hearing anything before the AMP.
Here is what they gave me. No surprise, every document and schematic displays the MOD section -AFTER- the AMP modeling and that is pretty much what I am hearing. The apparent gain increase is merely the circuit type which is designed to clip, the other effects are not distorting because they are not designed in that manner. Sort of like using a chorus, flange or phase after a high gain, it does not make the modulation distort. It is pretty easy to hear the issue of a modulation running into a gained amp or after it, the sweep and overall effect is reduced. When I experiment with the uber high gains like the 5150 and add an overdrive or boost I can hear the AMP model clipping the pedal model. The reason why it is not that big of a deal is because this is not really an Amp into a pedal or even an amp loop design. The AMP model is just a circuit not unlike a pedal and one is merely stacking. Any one should know when you stack to cleaner set pedals the gain distortion increases. Would have probably been more kosher to have split the MOD section more like PODs are designed for placement of effects but they just did not intend to do that so we use what we have. I just started messing with some of the COSM stuff and I can get some pretty nice high gain structures but I am not shelving my std guitar line and pedalboard.

Here is what Roland had to say, dumbed down as usual, because most guitar players are dense it seems.
If someone has a line on one of the GR-55 designers then you can pursue it further, but I am inclined to accept MOD is -AFTER- AMP.

Hi Paul,

The AMP model does indeed come before the MOD section. You can see this for yourself by navigating here:

1. Tap EDIT.
2. Tap PAGE to get to the EFFECT Tab.
3. Tap ENTER.
4. Tap PAGE to get to the STRUCT tab.
5. Here is where to ycan experiment with different routings, but the
AMP section always comes before the MOD section.



Kind Regards,
Roland Product Support
"Long ago in days of old when magic filled the air..."

gumtown

Check the input level is not too high if the effect is clipping, the input tone level goes from 0 ~100 and 50 is 'unity' or normal level.
Many seem to crank the input level to max which has two negative side effects.
1.) clips the input A/D conversion or the digital signal along the path due to limited headroom from the high level.
2.) makes gain control (guitar volume) less responsive to playing dynamics.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

Fusion

#14
Personally, I never use anything more than half volume, if that, I think POD users make that mistake early on under the premise one usually chains pedals, with the gain a little above unity into the next pedal, all you get on the digitial platform especially the POD is digital clipping on the input, certainly not "overdrive".
Digital input clipping can be a really ugly sounding thing, hard to imagine anyone mistaking that for harmonic musical distortion. I tested some more high gain AMPs today through my sound system and I have to say the end result is a pretty massive sounding high gain amp, on par with the better distortion pedals I have on hand. I tend to use the "warm OD, treble or clean boost" "after" my amp models which seems to create the better articulate more intense gain structure. I spent some playing time today switching from my guitar pedalboard Triple Wreck and the 55 models were on par with that level of intensity and articulation.

Also experimenting with the Hex Distortion on the GR300 COSM which I had overlooked previously until some started talking about the old Hex Distortion. This unit just continues to reveal more and more options, I am really pleased with the GR-55. The only downside I see to the overall AMP modeling mod thing is the inability to run more than a few effects in the overall chain, which all things considered I may have a bunch of pedals on my board but only a few at a time are on so really the GR-55 is just a great unit.
Does anyone know if the AMP models on the 55 are the same as the Boss models in the various floor units? I find these to be very good and I like so much better than the HD POD I messed with a couple years ago. The 55 does not suffer from the noise floor the PODs manifest and the AMP models to me are perhaps better.
The features of the POD were nice and the ENGL model was pretty interesting but all in all extremely noisy requiring an overt noise gate on every patch and the effect loop level was about -6db below unity. I took a loss on it just to end my pain. I find the GR-55 very quiet and amazing output levels. Pondering the GP-10 for some more interesting modeling stuff.

Bottom line on the GR-55 chaps - Roland claims all MOD is -AFTER- AMP and that is what I consistently hear.
"Long ago in days of old when magic filled the air..."

Fusion

"Long ago in days of old when magic filled the air..."

sixeight

Maybe you should try to do the same experiment I did in the first post of this topic. It might convince you otherwise.

gumtown

It most likely follows typical Roland/Boss fixed chain conventions, where modulation and drive effects are pre-amp, and time based effects are post-amp.
The N.S. probably sits just after the amp but is controlled by the signal just after the tone source.

"Digital Soup"
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

Fusion

Quote from: sixeight on May 16, 2015, 02:09:47 AM
Maybe you should try to do the same experiment I did in the first post of this topic. It might convince you otherwise.

I did oddly enough, but I do not hear what you are hearing as I explained, that is why I contacted Roland tech support because I am not hearing the amp model increase in gain because something is hitting it harder. Roland agrees the MOD is after the AMP. I suggest hearing can be somewhat illusory.
Since it is not really an "amp" it does not have the typical aghast reactions we would have of an amp running into a pedal or even a pedal in an amp loop that does not belong there. When they combine the Amp circuit is driving the boost/OD/Dist circuit, not that it sounds bad. I can get some rather amazing high gain tones out of the models with a nice sense of clipping and articulation. Some combinations do not sound good as the pedal model is digital clipping. But something pushing the AMP model into higher gain, that is not what I am hearing and seeing how for ages even now I use that resolve on my boards it does not sound quite the same. Even on a POD HD where you can move the pedal model pre or post you can notice the same thing, it is also is not really an "amp" into a pedal. Gain is increasing in the same manner if you do pedal stacking of overdrives, combining two moderate gain pedals results in the combination of increased gain together. Modulation units typically do not distort because they are not clipping circuits.
"Long ago in days of old when magic filled the air..."

Fusion

Hoping to clarify the matter before another person asks the question again:
"All" MOD effect models are AFTER the AMP section, Roland confirms this is so and all the schematics and docs are correct on the matter.
Sooooooo, to explain the difference in hitting the pedals in MOD with the amp or in front of the amp gain structure differences via listening to an A/B; I ran across something rather simple that just slipped my mind with all the "hearing the amp gain level gain" and so on:
Just crank the COSM Modeling Level KNOB to overdrive the amp model after unity, this serves as a nice clean transparent overdrive to push the amp model harder above unity level. This dramatically increases and effects the amp gain level and structure. Unity I surmise is around 2:00 to there is quite a bit of boost level available so just use enough to get the COSM AMP gain intensity where you like it.

Now if you listen to this gain structure intensity changing with the COSM knob at unity to boost range, and then try turning on a pedal with the COSM at unity and you will start to hear the gain structure of the AMP overdriving the pedal model, the distortion increases, but the clipping is coming from the pedal model circuit. You can hear the more digital clipping harshness and lack of articulation and clarity verses what is happening with the COSM Level Knob into the AMP model.

Personally for my ear, take any of the high gain amp models and get that COSM level where it is pushing the amp to dejent and you'll find you do not need any pedal after the amp in MOD unless you want some sort of thing not in the pedal Distortion section. I also find using the compressor or limiter after the AMP in the MOD or MFX section can be useful in controlling an intense gain structure and they will not clip and add distortion into the already dejent gain level.

I changed my new high gain AMP patches to use a higher COSM level and stopped using anything in the "Distortion" MOD section. Sounds much better, try it.
"Long ago in days of old when magic filled the air..."

gumtown

I'm not quite following which "knob" you are turning? the "COSM Knob" & COSM Amp" & "COSM Level"???
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

Fusion

Not as good as explaining things as you.
The COSM level is the knob on the Floorboard editor located on the COSM block. This runs into the AMP section which has its amp levels, and then into the MOD section and MFX if you route it.
The COSM level will overdrive the AMP verses the MOD overdrives AFTER the AMP.
Experimentation as to what sounds good and improves in the MOD section after the amp sound is tweaked in, is your taste and design. I find compressor and limiter can be useful as well. It is certain if you have the AMP level cranked you are going to digital clip the MOD section on any sort of overdrive or dist. I have got good results on some of the boosts. but watch about the signal level coming off the amp model.
One has to find the most novel level of the COSM as well as the AMP gain and level for the best articulate and defined distortion quality.
"Long ago in days of old when magic filled the air..."

eniovasconcellos

Sorry. I know it is an ancient disussion, but I finally got a good sound with this box. I have considered that the sound the cabinet simulation of a clean amp like boss clean or tweed clean is much better than high gain amps. then I installed a loop effect (found in this forum) and put a real boss ds-1  into it and "bingo!" . GR-55 - > boss ds-1(loop)  -> GR-55 (boss clean amp)

AngeloEvs

For that classic 'country' sound, a compressor must be placed before the pre amp, having the compressor after the amp sounds completely wrong.    There is a way round the problem of Roland putting the 'Mod compressor' after the amp.   I use routing 2, send the normal PU or Modelling PU to mod/amp and select the mod compressor but switch the amp model switch to 'off'.   I use one of the MFX amps instead.  I find that I can get equally good tones using the MFX amps, good choice of cabs or none if preferred, and I like the ability to switch the mic off or balance the natural sound with the mic option.