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HELP: Modular synth causing humm in other studio gear
MUFF WIGGLER Forum Index -> Modular Synth General Discussion  
Author HELP: Modular synth causing humm in other studio gear
aswefallintostatic
Hey guys,

So i have noticed that my eurorack cause (a 6U monorocket) is causing quite significant noise in some of my external studio gear.

I power everything off a Furman power conditioner, but for whatever reason, powering my Eurorack form the same power source seems to create a pretty significant hum in various bits of my outboard gear. Even with no audio cables plugged in, just the power the noise is induced.

Switching to powering the modular from a different source seems to solve the problem, but its a pain when the rest of the studio seems to happily play ball with a universal powering system

Is there anything i can do to avoid this? Could it be a problem in my modular? might another power solution solve this?

Any tips / advice / similar experiences welcome please!

T
Rex Coil 7
... what type of power supply/power distribution are you using in your modular cabinet? ...
psymbionic
If you already have a Furman, you may try ferrite noise suppressors. They are the little cylindrical things that you often see attached to power adapters and the like. For me, they removed noise like being able to hear appliances in the other room turning off/on in my system (old house, bad grounding). They'll also removed noise such as picking up AM radio on a badly shielded guitar cable.

Super cheap on Amazon, get a few different sizes for different size cords.
9mm seem to fit over 1/4" cables quite snugly, 7mm works well for normal USB/power cables on a lot of things. I run them on all my studio gear and it made a big difference, especially when I have my monitors cranked up.

https://www.amazon.com/gp/product/B00CIQH0CA/ref=ppx_yo_dt_b_search_as in_title?ie=UTF8&psc=1
Pelsea
So you plug your synthesizer into the Furman and everything else in the studio starts humming? What model Furman is this?
Dave Peck
You said 'even with no audio cables plugged in".

But what about midi or USB cables coming from a DAW, hardware sequencer or other audio gear in your setup? Anything like that plugged into your modular?
Keltie
We need to invoke Hinton here.... let me initiate the calling ritual...

*ahem*

Oh great Hinton, we say unto you.....Flying busscables are an excellent power source, and wall wart power supplies are the hallmarks of excellent power engineering

He’ll be along shortly, I’m sure.
Rex Coil 7
qu.one
Dave Peck wrote:
You said 'even with no audio cables plugged in".

But what about midi or USB cables coming from a DAW, hardware sequencer or other audio gear in your setup? Anything like that plugged into your modular?


This + what kind of connection is between your setup and monitors? using balanced for audio output to speakers can be a big improvement.
Graham Hinton
aswefallintostatic wrote:

So i have noticed that my eurorack cause (a 6U monorocket) is causing quite significant noise in some of my external studio gear.

I power everything off a Furman power conditioner, but for whatever reason, powering my Eurorack form the same power source seems to create a pretty significant hum in various bits of my outboard gear.


Eurorack + Monorocket + Furman = a perfect storm.

Is the Furman one if the "balanced power" types?

Quote:
Even with no audio cables plugged in, just the power the noise is induced.


So how do you hear a hum? On what and how is it connected?

You need to provide a level of detail that you have not shown so far.

Quote:

Is there anything i can do to avoid this? Could it be a problem in my modular?


Get rid of the Furman first and replace with a normal mains distro.
If that doesn't improve get rid of the Monorocket.

psymbionic wrote:
If you already have a Furman, you may try ferrite noise suppressors.


Snake oil. Surge suppressors and radio frequency noise filters will have absolutely no effect on a hum problem or any other audible noise.
aswefallintostatic
Thanks for the replies everyone! (side note, i didnt seem to get any notifications to this thread, weird...)

The furmann is this on: https://www.thomann.de/gb/furman_m10x_e.htm?sid=5467a151d1695acc9ff9f2 774a9aa96c

Not sure if that makes it a 'balanced power' type. What would be a better solution for power distribution?

The modular is on a metal stand, and connected via three audio cables to a patch bay / pre amps, there is also a 5 pin DIN midi cable coming from an OB6 (also powered from the furman). It has an internal power supply that came with the case, that connects via a standard kettle lead.



They type of noise is a relatively grainy mains hum, particularly prominent around 150hz.

I am thinking of building a new case for the modular anyways (unrelated to noise problems) so any suggestions of the best power solutions would be welcome to minimise noise!

Thanks
T[/img]
Rex Coil 7
dbl post
ranix
recording the hum could expose a lot of information, most of the content should be in the audio range and we can examine it and speculate on source
Graham Hinton
aswefallintostatic wrote:

Not sure if that makes it a 'balanced power' type. What would be a better solution for power distribution?


That one is not "balanced", which should be avoided, and is OK.

Quote:

The modular is on a metal stand, and connected via three audio cables to a patch bay / pre amps,


What sort of cables are you using?

Quote:

there is also a 5 pin DIN midi cable coming from an OB6 (also powered from the furman).


A MIDI cable should not have the screen connected to the plug shells and the MIDI In pin 2 should not be connected. There are many "MIDI" cables in circulation that are incorrectly wired and will defeat MIDI's opto-isolation. Check continuity between the MIDI cable shell and a patch cable screen--there should be none.

Quote:
It has an internal power supply that came with the case, that connects via a standard kettle lead.


You will find that is an IEC C13 lead and will not plug in to a kettle. Kettles use a C15.
At least that should bring a mains Earth to the case. The question now is whether it is used correctly inside and whether you have an Earth in the wall outlet? What country are you in?

Quote:

They type of noise is a relatively grainy mains hum, particularly prominent around 150hz.


A mains harmonic (from rectification) indicates a PSU problem. It is most likely either incorrectly earthed or not earthed at all. You can check that by measuring continuity (or not) between the Earth pin of the mains lead and the screen of a patch cable plugged in a module.
ranix
Graham Hinton wrote:

psymbionic wrote:
If you already have a Furman, you may try ferrite noise suppressors.


Snake oil. Surge suppressors and radio frequency noise filters will have absolutely no effect on a hum problem or any other audible noise.


Ferrite suppressors in particular are like low-pass filters. They affect higher frequencies more than lower frequencies, so they would certainly pass the noise in question since it's in the audible range.
aswefallintostatic
So i re-plugged the modular into the furman in order to record the sound it makes and it was no longer happening. Very odd, when i made the post it seemed quite consistently, over several days, to be the cause of the problem.

There have not been any significant other changes in the studio, although i will have re-patched everything in a myriad of different ways in the meantime.

Could a crappy patch bay be causing problems? I am using one of the cheap neutrik ones and sometimes have to jiggle cables... i have a tech building me a soldered bay, but it seems to be taking a while!

PS - I am in berlin, Germany, but the power in the building is pretty bad, the first time i plugged in the OB6 it died, i had to send it back (and immediately ordered the furman!)

Thanks again for your help here! I'lll keep the modular plugged in to the furman and grab a recording of the noise it causes if it happens again, and try to work out what i did that made it happen!

Best
Tom
Graham Hinton
aswefallintostatic wrote:
Could a crappy patch bay be causing problems? I am using one of the cheap neutrik ones and sometimes have to jiggle cables... i have a tech building me a soldered bay, but it seems to be taking a while!


It could be a problem if you have a mixture of earthed and unearthed equipment.

Quote:

PS - I am in berlin, Germany, but the power in the building is pretty bad, the first time i plugged in the OB6 it died, i had to send it back (and immediately ordered the furman!)


That's your clue. Equipment, like the OB6, that has IEC mains inlets expects the Live and Neutral to be on the correct pins and an Earth. Unfortunately in Germany there is a 50% chance of either making a 25% chance of a correct mains supply. Many international manufacturers are unaware of the German "Schuko problem".

Before you had the Furman did you have a Schuko plug on each mains lead?
By using an IEC mains distributor and IEC-IEC leads all the equipment will have its mains the same way round, but you still only have a 25% chance of the wall outlet being right.

Get a mains socket tester, the sort with three LEDs, and check that your wall outlet is correctly wired (if not get an electrician) then make sure that you know which pin is Live on the lead going to the Furman and always plug it in the right way around. I know someone in Germany who tested every mains lead in his studio and meticulously painted blue and brown dots on every Schuko plug, but it is a lot easier to not use Schuko plugs.
aswefallintostatic
Graham Hinton wrote:


Get a mains socket tester, the sort with three LEDs, and check that your wall outlet is correctly wired (if not get an electrician) then make sure that you know which pin is Live on the lead going to the Furman and always plug it in the right way around. I know someone in Germany who tested every mains lead in his studio and meticulously painted blue and brown dots on every Schuko plug, but it is a lot easier to not use Schuko plugs.


Thanks for the advice, yep everythign was just Schuko multi plugs before the furmann. This seems like a good place to look next in terms of sorting out the power situation.

Thanks for the help

T
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