[solved] High noise level at all times

Using MOD devices
#81

I never used one, I use noise reduction when needed often directly in the amp or in the pedal (Source audio, PX5, many have now).
Does a hum destroyer so cheap manages to do the balanced to unbalanced transformation, may be taking care of the final impedance which an inverted DI Box does not do ?

#82

I think MOD just updated their website with official specs for the Dwarf. It now says:

Dual 6.35mm TRS independent audio outputs, with gain configurable from 0dB to -127dB, balanced or unbalanced

Seems like they suggest even an unbalanced 1/4 should be fine
. I can’t wait for more people to get their dwarf in-hand to compare. Maybe something is faulty with my unit.

Anyhow. I should get my isolating transformer on Sunday. Hopefully Monday I will have some time to do some troubleshooting. I’ll try to come up with an exhaustive list of possible configurations and shoot a video showing how it behaves in each situation.

3 Likes
#83

Yes: hum destroyer = audio isolation transformer (in most cases).

I’ve been fiercely advocating audio isolation transformers in lieu of ground lifting. I stated earlier on the thread that DI boxes are not for curbing hum but instead matching impedances – though some ALSO do that. Audio transformers are the safest and surest way to deal with ground loops. (I did not advocate for DI boxes.)

Now, beware of 2 things:

  1. There’s the $5 transformer and the $50 one. Don’t buy a cheap “hum destroyer” and ask it to be crystal silent;

  2. There are some “hum destroyer” boxes that simply employ a low pass filter, considering the frequency of the low E guitar string at 82Hz on standard tuning. They “cleverly” state that the box is for 6-string guitars only – no basses or 7+ string guitars.

And there another thing worth noticing: it is possible to filter the power line as opposed to the audio line! Since the entire issue of ground loops is related to having two or more powered audio sources connected to the AC power line, filtering one or more of them works the same magic. :slight_smile:

(What I have been pounding hard at since my first post here is to avoid simply lifting the ground, much less in the AC cord of your devices/amps.)

For instance, the very Palmer mentioned by @mj_prod above produces a DC line filter for that purpose (~20 Euro):

Years ago, I had an AC filter where I could plug the laptop for playing live. It was heavy, cumbersome, and had a tendency to overheat. A DC filter like this one is much lighter and simpler.

Also, for the folks with the same problem as @CSurieux, there’s the REAMPING route: a impedance matching box that allows the connection of balanced or line level signals into a guitar amp, and there are plenty of options in the market. This box also from Palmer will take a balanced signal at 600 Ohm and output an unbalanced signal at 100 K ohm – and it has an audio isolating transformer. (Disclaimer: I am not affiliated with Palmer and do not own either device.)

Therefore, between filtering the audio and power lines, it is possible to curb hum and have fun with our MOD devices, safely.

I doubt it, cheaper ones will not do impedance matching. The difference in price for a low impedance to a high impedance audio transformer is easily around 200%, if not more.

Thanks for posting that, @jeffutter. That answers the question we’ve been asking.

3 Likes
#84

I have same big hum problem as you, on first try for solution I used an inverted DI Box (cheap one DI400 from Thomann) connected with a TRS to Dwarf an a TS to my amp and the hum was reduced but I will further test this hum pb.

I am puzzled with all these solutions to a pb I was not expecting.
I use Strymon power for all my pedalboard and have never encountered such a pb.
One time I got a Positive Grid Spark and there has been same huge hum pb, Positive Grid send me another power and it solved the pb. later I sold the Spark because it was not adapted to my way of playing.
I heard @QuestionMarc (certainly a Palmer guy :wink: ) 's solution but don’t want to get implied in another technical thread.
I read @shaggydog arguments for a hum destroyer, but I need to better understand how to connect it (TRS/TS) and I am not sure of the adaptation of this solution to the problem ??
I want to be able to place external pedal before and after the Dwarf and connect this to my amp, connection to an audio interface seems to be much simpler.
May be the solution would be to add a noise reduction pedal inside each Dwarf board I will build, just as in the TC Electronic PX5 where you could add a noise limiter pedal ?
But does such pedal exist in all the available stuff, where to search for, Utilities ?
For me it would be the easier solution without adding another brick in the pedalboard and more controls to do on each session, and may be (yes I know they are very busy) MOD team could improve it to solve actual problem ?

#85

Thank you - you obviously have far more knowledge than me on this topic! I use one of these, and not had any problems that I’ve noticed so far . . . Behringer | Product | HD400

1 Like
#86

The comments on this cheap Behringer HD400 are very positive, I may try it.
Some comments say it is coloring the sound and limiting it (that’s my fear) , some other say it should be used with a noise gate in complement (for me the noise gate should be enough ??), and few others say it has no effect on their hum pb.
Is anyone knowing if it exists a noise gate pedal in those accessible with the Dwarf ?

#87

abGate is one of them.

FYI for v1.11 the Dwarf will have an internal integrated noise-gate, controllable from the screen.
Though that applies only to the inputs, not the outputs.

4 Likes
#88

Thank you, I will try.
One side question, I started to read the Mod Github repos and noticed that you are the owner of quite all of them (impressive), are you the lead dev ?

#89

Thanks, but I have not. I’m just curious and research a lot – I guess that comes by default with being a librarian! :wink: Also, this whole ground loop thing has already caused me a lot of problem. Like others here, I too had a bandmate with a serious “oh-gosh!-I-hear-a-buzz” syndrome


Oops, when I edited my post I accidentally deleted the disclaimer. Sorry! :astonished: It’s back there now. Actually, I never used Palmer gear, but I am indeed partial to German Audio engineering (as well as Italian hazelnut chocolate, French crĂȘpes and Gratin Dauphinois, African fufu and afrobeat. You will never see me badmouth any of these! :wink:)

I did own Lehle boxes, and those were REALLY good, sturdy, silent, and absolutely reliable. I once drove off to the highway with my bag on top of the car! It fell off at 110 km/h, everything inside broke – except the Lehle box!! I used it all scratched for several years afterwards.

That will help. As a matter of fact, most of the high-end guitar software comes with a noise gate active by default. The ‘modelling’ process creates a lot of hissing (more than hum).

Precisely! Strymon power sources are fully isolated, so you won’t have problems with ground loops. And they are expensive – the 9 output Zuma model is nearly 300 Euro! (Too bad the 12V port is only 375 mA
)

This works, but you lose a lot of signal strength. For a full solution, you would need the reamp box. Here’s a non-Palmer solution form England’s Orchid Electronics. (~60 GBP)

But remember these can get nasty expensive, like the Radial Engineering boxes.

3 Likes
#90

on the OS related things, yes.

There are other people doing other things, of course.

2 Likes
#91

Thanks for sharing this, I also use lot of German made gears and eat Italian and French (easy) food :wink:
Yes Radial is very good but so expensive.
All these boxes we must add all around our boards are definitively a pain, Dwarf is presented as a different object so I will try to push the pain a little further
but it’s hard.
When time to market is too long it may occurs that a solution which was looking as innovative has simply missed current evolution of market ?

#92

I don’t think that’s the case. The MOD took about the same time as some of its competitors who also used crowdfunding: PiSound, Zynthian, etc. The MOD is innovative in its own way, specially on the OS side of things – so much so that both of these used the MODEP environment.

As it is, the MOD is pretty much aligned with its main competitors, in terms of multi-effect, self-contained, Linux kernel-based boxes: Poly Effects, the Empress Zoia (arguably one of the most incredibly powerful boxes money can buy.) The MOD is far superior to both PiSound and Zynthian. (PiSound’s input is 100KOhm, so it’s nearly unusable with a guitar.)

I guess the problem with impedances and noise is more related to the nature of the product: DSP chips are still too temperamental, highly susceptible to the environment. For instance, even cheap LED bulbs in our homes are interfering with our computers and will also impact the MOD. Moreover, the broader environment also interferes. I live in a street with a warehouse where they do soldering, and every time they power up the soldering machine, all modems around lose connection temporarily due to the blast of the capacitors on that thing! :face_with_symbols_over_mouth:

(It can also be the cathode tube oscilloscope they have there, which causes an RF blast when turned on.)

My suggestion is always: go from small to big. Try a different cable (50% of the times the cable itself causes hum, even some ‘cool’ ones highly advertised on magazines!). Then try with a different amp, if you have one. Then plug them in a different room and/or in the same outlet. If all of these fail, then try one of the other solutions involving hardware.

(A massive issue with the Apogee Duet units back in their day is that the breakout cable failed fairly quickly and it caused a lot of noise. RME Babyface users had the same problem.)

Good luck!

2 Likes
#93

abGate looks more as an envelop filter than as a noise gate ?

image
image1832×345 72.7 KB

#94

From https://en.wikipedia.org/wiki/Noise_gate:

Gates typically feature “attack”, “release”, and “hold” settings and may feature a “look-ahead” function

and

Noise gates have a threshold control to set the level at which the gate will open. More advanced noise gates have more features.

The release control is used to define the length of time the gate takes to change from open to fully closed. It is the fade-out duration. A fast release abruptly cuts off the sound, whereas a slower release smoothly attenuates the signal from open to closed, resulting in a slow fade-out. If the release time is too short, a click can be heard when the gate re-opens.[citation needed] Release is the second-most common control to find on a gate, after threshold.

The attack control is used to define the length of time the gate takes to change from closed to fully open. It is the fade-in duration.

The hold control is used to define the length of time the gate will stay fully open after the signal falls below the threshold, and before the release period is commenced. The hold control is often set to ensure the gate does not close during short pauses between words or sentences in a speech signal.[4]

The range control is used to set the amount of attenuation to be applied to the signal when the gate is closed. Often there will be complete attenuation, that is no signal will pass when the gate is closed. In some circumstances, complete attenuation is not desired and the range can be changed.

1 Like
#95

and are using dedicated algorithm to control noise

 and more similar to what guitar players use since years.
I won’t show you the buttons of a EHX Sillencer or a TC Sentry or my Source Audio L.A Lady or even my Hughes & Kettner amps.
And won’t show you the envelop filters of any of my synths but you could easily see that this is more similar to an envelop filter.
I don’t want to sculpt sound but remove noise created by Dwarf
if they are on its input side


#96

Just wait for the v1.11 then, or if you want I can PM you a preview build that already has the integrated internal processing (but not everything is finalized yet).
It should be just 1 or 2 more weeks, then some time for final internal testing and planning (we have the idea of having beta backers in v1.11-RC1 with an opt-out option, more details later on)

3 Likes
#97

@falkTX just to be clear the 1.11 update should only help with noise from the line in, right? If I get noise with nothing plugged in and no plugins loaded that wouldn’t change.

  • just want to make sure before I spend a bunch of time troubleshooting.
1 Like
#98

Correct.
Though we are still testing some tweaks in the “noise-removal” tool that hits the cpu on the background to keep it busy.
Previously we had it enabled, but causes the unit to warm up too much.
So there might be something in there that helps this case. Want to PM you a preview build? it is easy to switch back at any time.

1 Like
#99

@falkTX sure I’ll try a preview. I thought I had less noise (but still some) before the 1.10.1 build came out. I think I only had the Dwarf for a day before 1.10.1 came out so I may be misremembering that.

I’d be glad to try that out with the rest of my testing when I have time on Monday

2 Likes
#100

I can also do testing with this preview build if you get time to PM it to me.