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G3n, G3nx, G5n, and Guitar Lab

Posted: Tue Mar 13, 2018 11:00 am
by stubbsonic
In other threads, I've reported an RFI issue with my MS100-BT at my regular theater gig.

I tried a few other models (Pod HD500, GT-1, RP360 and RP255) but they all lacked clarity and dynamics for the sounds I need right now-- clean fender tones. The MS-100BT beats them all-- with the possible exception of the RP360 which seemed pretty good (but I couldn't A-B it with the MS). I'm hoping that the G3n (and its variations) are more immune to the RFI issue, and that this is just a fluke with the MS series.

I installed the Guitar Lab software, and was able to see what additional modules were available. The app didn't specify which modules were built-in, and which needed to be added, but I suspect that would be more clear after I connected a device (which I haven't purchased yet).

For me, the G3n seems sufficient. If I need a pedal I can connect one, but I don't use one very often. The sounds seem like they are going to be at least similar to the MS series-- or perhaps better (?)

Any thoughts? Should I place the order?

Re: G3n, G3nx, G5n, and Guitar Lab

Posted: Tue Mar 13, 2018 12:44 pm
by NucleusX
As you probably already know, I'm trying to figure out the issue with the MultiStomp series
myself. This problem has also been reported by G5 and G3 users as-well, which all share
the same software/firmware and hardware in their DNA. The G5n and G3n are the first
pedals from Zoom to depart from that DNA, and have been revised from the ground up,
or so it seems. Still waiting for a G5n owner to confirm what the installed DSP chip is, to
make that certain. Aside from that, they seem like a new beast altogether that focuses
more on amp-sim quality, and less on simultaneous effects. Recently, I said i was going
to try and look harder into the noise problem, and have only just got around to it. I was
advised by another forum user that the noise could be attributed to the input/impedance's,
and that having a buffered pedal placed before a MultiStomp could resolve this. I had to
put some thought into what that pedal might be, and ended up with a BOSS TU-3W, which
is the Waza variation of their famous TU-3. Reason i chose it, was the fact it has a selector
switch on it for true bypass and buffered. It also had to be the type of pedal you would
expect to find early on in the chain. I've only just made the required alterations to my
pedalboard to accommodate it, but soon i will start messing around with them, and passive
or active guitars, to see what kind of results i end up with, and to see if its even a manageable
problem. Its up to you whether you cant wait to pull the trigger on the new one, the G5n or
G3n certainly shine where you want them to for your purpose (amps), but i wouldn't go basing
your decision on the previous Zoom FX pedals, they are just too different.

Re: G3n, G3nx, G5n, and Guitar Lab

Posted: Tue Mar 13, 2018 2:17 pm
by stubbsonic
I didn't realize you had the same issue.


It's also helpful to know that the issue was reported with the G3 and G5. Since the n versions are different hardware, perhaps it will be different.

At any rate, I can pick up a G3n, and try it at the theater, and return it if it exhibits the same problem. I'd be out the shipping cost, but if it works, it will be an important problem solved. I wish I could use the Guitar Lab to load bass amps intended for the B3n onto the G3n, but surely the software will prohibit this.

Re: G3n, G3nx, G5n, and Guitar Lab

Posted: Wed Mar 14, 2018 10:58 am
by NucleusX
stubbsonic wrote:
Tue Mar 13, 2018 2:17 pm
I didn't realize you had the same issue.
Not exactly the same, but we discuss it in one of your threads.


This thread should clarify things for you even more.


The one i discuss has been a common issue for as long as i remember, and
there may be a link between both issues here I'm thinking, hard to say.

I'm sure if the G3n arrives in pristine order, you'll be pleased with it's amp
tones. Coming in this late in the game is a good move too. Zoom have
been slowly dribbling out updates for them over the last couple years, so
by now, you'll have access to a lot more updates, amps and FX once you
connect it to guitar lab. Zoom doesn't seem to be done with those updates
yet, so expect more soon. Good quality cables will go a long way with RF.
If you use a long guitar cable, make sure your first pedal is buffered.

Re: G3n, G3nx, G5n, and Guitar Lab

Posted: Wed Mar 14, 2018 11:37 am
by stubbsonic
Thanks, NucleusX. I wasn't thinking of the "artifacts" or "high pitched whine" symptoms as RF, but perhaps you're right.

I posted a few more details on my "ferrite beads" thread.

Re: G3n, G3nx, G5n, and Guitar Lab

Posted: Wed Mar 14, 2018 12:03 pm
by NucleusX
This is the post that set me off.
EvtoDJ wrote:
Mon Jan 22, 2018 6:48 pm
The topic is fairly old, but anyway....
The MS series high pitched whistling is probably a noise from the internal SMPS voltage converter, that the high impedande input stage easily picks up.
It is even more obvious if you lift the pedal while playing through it, and put it near your guitar's pickups - even outside the pedal's metal enclosure, it still emits this noise around.

If you want to get rid of it almost completely, to the level where the pedal may be used for high-gain sounds, just put another NON-TRUE-BYPASS (electronic bypass, for example BOSS) pedal in front of if, with the bypass mode engaged, so that you use the pedal as a simple high-to-low impedance converter (buffer).
If this guy is correct, then its quite possible that these issues are related.
Electronically, his theory surrounding the power section carries weight.

Re: G3n, G3nx, G5n, and Guitar Lab

Posted: Wed Mar 14, 2018 1:35 pm
by stubbsonic
That makes total sense. I don't know what an SMPS voltage converter is, but I will try some various things at input to see if I can reduce the issue.

Re: G3n, G3nx, G5n, and Guitar Lab

Posted: Wed Mar 14, 2018 7:11 pm
by NucleusX
SMPS stands for for Switchmode Power Supply, which are what you find in things like mobile chargers,
to computer PSU's. As opposed to the old fashion linear 50-60hz transformer based power supplies,
the switching power supply operates at a frequency anywhere from 10Khz, to 1Mhz. Due to poor
filtering or manufacturing, these high frequencies can induce audible noise via common power rails or
coil-whine, and usually will be heard in the higher end of the frequency spectrum. At some point, we've
all come across a power brick or plug pack that emitted a high pitched squeal, its a common problem.

Re: G3n, G3nx, G5n, and Guitar Lab

Posted: Wed Mar 14, 2018 10:58 pm
by stubbsonic
So perhaps if the SMPS is running at some frequency related to the frequency of the wireless mics, it could demodulate the signal? That seems possible.

Re: G3n, G3nx, G5n, and Guitar Lab

Posted: Thu Mar 15, 2018 11:37 am
by NucleusX
The common denominator i see with the power section theory is the RF component. With your problem,
the RF is induced externally, with the other problem we've been discussing, it seems to be internally
generated by pedal itself. This seems indicative or poor filtering, grounding or shielding. The noise we
hear is a constant high pitched carrier somewhere around the 5khz region. Its possible that its coming
from the power section with its operating frequency modulated into the audio spectrum via a division of
harmonics. Where as with your problem, the wireless RF could be bleeding through the same filtering.
Different symptoms of the same root cause if you will. Switchmodes can cause all sorts of RF havok, even
at 1Mhz with harmonic orders, which can be heard if the unit hasn't been thoroughly filtered or shielded.
Its tempting to assume Zoom cut corners here to keep manufacturing costs down, being budget oriented.