[solved] High noise level at all times

Using MOD devices
#74

Thanks for your inputs, @CSurieux.

Could be. And to some extent it makes sense. Mod devices might be willing to position their products as competitors to modelers like Line6 Helix, Kemper, Headrush, as well as some of the latest Boss GT and SY units. These are all designed to be connected straight into FRFR speakers or full range amplifiers, both of which will have balanced TRS/XLR inputs. It seems to be the direction the market is going now.

(Bossā€™ excellent MS3 unit is more of a traditional multi-effects box, and in spite of being cheap, incredibly flexible and powerful, itā€™s selling so bad that it might be discontinued soon.)

Also, MOD boxes also have sequencers, midi instruments, audio players, noise generators, synths, ā€¦, all of which require full range amps.

I would not think that to be the case, since @gianfranco, @jon and others at MOD Devices are essentially guitar players. I would bet on what I said above.

The OD mode of most amps start by having some 12-15dBs of extra sensitivity to the input signal (and not by boosting the signal internally, which would be preferable but is more expensive). If you already have hum, using OD mode makes it much worse, sadly.

That is not the point I was making. Balanced or unbalanced as the audio may be, isolating transformers would be required to remove hum from them (they do not only convert impedances). My point was that, in order to prevent hum straight out of the box, they would need those. And it doesnā€™t make sense to employ them, unless you have a super high-grade device like RMEs, Apogee, Universal Audio, etc.

As I said before, we need to wait to hear from them as to if the outputs are balanced only and, in that case, their reasoning for that.

(Disclaimer: I did not participate in either Kickstarter or Indiegogoā€™s crowdfunding effors, so I donā€™t know for sure what was promised for the Dwarf.)

I think it was marked ā€œsolvedā€ back in 2018, when the first posts got in. Itā€™s just that we kept talking about it and others peeked in searching for the same answers.

2 Likes
#75

Ha Ha we are on different planets.

#76

I accept the cumpliment! :wink:

4 Likes
#77

No native Fx loop and balanced TRS stereo output, this product is clearly not conceived for use with any guitar amp ?

#78

There seems to be much talk on here of the need for a DI box to kill the hum, but a hum destroyer will perform the same task by getting rid of the ground loop. Less than Ā£20 for one that will work on two channels.

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#79

Sorry - we - not robots- :wink:
But I agree that adding a cheap DI box seems to do the trick, but very unusual for most of us using more often amps than audio interfaces, and it is one more piece in the puzzle.

#80

I agree itā€™s unusual, but the Mod boxes arenā€™t like other pedals that Iā€™ve come across in many ways, and I donā€™t object to a balanced out. As I said, a hum destroyer works fine, and is cheaper than a DI box.

1 Like
#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 fineā€¦. I canā€™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. Iā€™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).

Iā€™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 ā€“ 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. Thereā€™s the $5 transformer and the $50 one. Donā€™t buy a cheap ā€œhum destroyerā€ and ask it to be crystal silent;

  2. There are some ā€œhum destroyerā€ boxes that simply employ a low pass filter, considering the frequency of the low E guitar string at 82Hz on standard tuning. They ā€œcleverlyā€ state that the box is for 6-string guitars only ā€“ 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, thereā€™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 ā€“ 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 weā€™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 donā€™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 Iā€™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 (thatā€™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. Iā€™m just curious and research a lot ā€“ 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 ā€œoh-gosh!-I-hear-a-buzzā€ syndromeā€¦

Oops, when I edited my post I accidentally deleted the disclaimer. Sorry! :astonished: Itā€™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 crĆŖpes 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 ā€“ 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 ā€˜modellingā€™ process creates a lot of hissing (more than hum).

Precisely! Strymon power sources are fully isolated, so you wonā€™t have problems with ground loops. And they are expensive ā€“ the 9 output Zuma model is nearly 300 Euro! (Too bad the 12V port is only 375 mAā€¦)

This works, but you lose a lot of signal strength. For a full solution, you would need the reamp box. Hereā€™s a non-Palmer solution form Englandā€™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.

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#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 furtherā€¦but itā€™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 donā€™t think thatā€™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 ā€“ 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. (PiSoundā€™s input is 100KOhm, so itā€™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 ā€˜coolā€™ 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!

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#93

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

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