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Going INSANE from newly acquired ground noise(?)
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Author Going INSANE from newly acquired ground noise(?)
glassofwater
Hi,

My setup is 2 x A-100LCB Low Cost Base [PSU3] and 2 x Doepfer A-100LC9 [PSU3]. All of them are filled up with modules.

I've had this setup for a while, but a few weeks ago an insane amount of noise started appearing. This setup has been rock solid and have had ZERO noise. Check out these mp3's for example:

Loading a sample on the 1010music Bitbox: https://www.dropbox.com/s/rs3dj8ciagtgro6/bitbox%20loading%20a%20file. mp3?dl=0
Erbe-verb plugged in and out, plugging in and out VCAs etc: https://www.dropbox.com/s/ardhgsezub2vv3h/a%20mix%20of%20plugging%20in %20and%20out%20erbeverb%20or%20vcas%20etc.mp3?dl=0

Usually everything is going into one of the cases where i have 4 x Doepfer performance mixers, but the sound happens if I plug from the modules straight into either the uJack (and monitoring with headphones), into my soundcard (ground lift on/off, doesn't help) or my Tapco mixer.

My first try at a solution was buying an Ebtech hum eliminator and run the whole thing (or trying out seperate modules) through that. Didn't work. TRS-cables or not, no change.

I then got a Furman M-10x E power conditioner and now run my entire room through that (so, the four modular cases, my speakers, my PC (both case and screen) and the previously mentioned mixer). Still, no luck.

Oh, and I also tried this in two different rooms in my apartment.

I also have a Doepfer A-100LC3 [PSU2] laying around, so I just tried a few of the noisiest modules (Erbe and Bitbox) plugged into that and there's zero noise, just like I'm used to! Bliss!

So after all this I'm guessing there's something up with the PSU3's in my Doepfer cases? Seems like something happened to all 4 of them at the same time?? Does anyone have any ideas?

Much love to anyone who's willing to help me with this. <3<3<3
glassofwater
In case it's interesting:

Top left case: 861 mA +12V, 455 mA -12V, 0 mA 5V

Bottom left case: 1045 mA +12V, 215 mA -12V, 0 mA 5V

Top right case: 976 mA +12V, 635 mA -12V, 120 mA 5V

Bottom right case: 431 mA +12V, 263 mA -12V, 0 mA 5V

(according to modulargrid)

Also I'm based in Europe with 230 V.
ookrsia
This thread has a lot of information and conversation related to reducing unwanted noise when using multiple PSUs: https://www.muffwiggler.com/forum/viewtopic.php?t=198100&postdays=0&po storder=asc&start=0

It might be useful to you.
Reckless_Experimenter
sounds like you are not getting a good ground between the cases.
Or possibly an earth ground on the AC side of one or more power supplies may have become disconnected.

I would start by just patching in modules from one case at a time into your sound recorder, and see if you can narrow it down to one case. Then investigate in the internals of that one to see if you can spot the problem.
glassofwater
Yeah, this might be it. Just so weird that it suddenly started happening. It's been fine for ~2 years.

Gonna check the PSU's tomorrow a bit more closely. Thanks everyone.
Mungo
glassofwater wrote:
Usually everything is going into one of the cases where i have 4 x Doepfer performance mixers, but the sound happens if I plug from the modules straight into either the uJack (and monitoring with headphones), into my soundcard (ground lift on/off, doesn't help) or my Tapco mixer.
First unplug all cables connecting the cases and try listening directly with headphones plugged into the different cases/modules (not using the headphone module!) before anything it patched. Is it there in all the cases? Or just one? Or only some modules?

glassofwater wrote:
My first try at a solution was buying an Ebtech hum eliminator and run the whole thing (or trying out seperate modules) through that. Didn't work. TRS-cables or not, no change.
The TRS cable only works if there are balanced connections at both ends like an output module, or you get the special pseudo balanced cables for unbalanced into balanced. But the hum eliminator would have shown up if this was an ground/earth loop (if you didn't have any other cables connecting between the equipment at the time).

glassofwater wrote:
I then got a Furman M-10x E power conditioner and now run my entire room through that (so, the four modular cases, my speakers, my PC (both case and screen) and the previously mentioned mixer). Still, no luck.
Many of the power conditioner products are nothing more than a power board, convenient to be sure but unlikely to make any improvement to noise.

glassofwater wrote:
Oh, and I also tried this in two different rooms in my apartment.
Same result elsewhere?

glassofwater wrote:
I also have a Doepfer A-100LC3 [PSU2] laying around, so I just tried a few of the noisiest modules (Erbe and Bitbox) plugged into that and there's zero noise, just like I'm used to! Bliss!
Which suggests its actually the power inside the cases, and probably not the same in all cases simultaneously.

glassofwater wrote:
So after all this I'm guessing there's something up with the PSU3's in my Doepfer cases? Seems like something happened to all 4 of them at the same time?? Does anyone have any ideas?
Its possible but unlikely that all cases had problems at the same time, by using each on its own with no other equipment patched to it and listening with headphones you can check if they all have problems or its just one of them. Once they're all patched together it may be audible in all the cases even though only one of them has problems.
tbecker
glassofwater wrote:
In case it's interesting:

Top left case: 861 mA +12V, 455 mA -12V, 0 mA 5V

Bottom left case: 1045 mA +12V, 215 mA -12V, 0 mA 5V

Top right case: 976 mA +12V, 635 mA -12V, 120 mA 5V

Bottom right case: 431 mA +12V, 263 mA -12V, 0 mA 5V

(according to modulargrid)

Also I'm based in Europe with 230 V.


Have you used the power regulator or a AC volt meter to monitor the incoming voltage? No magic that anyone can offer you will help when you are running out of spec on the switching supply. I have seen voltage drop to 85v in the US or as high as 140v with frequencies far deviating from 60 Hz. Anyway what does your input voltage look like?
Tonefloat01
Whatever you changed and/or rearranged and/or acquired since the ground loop, undo it all in reverse order and the culprit should soon reveal itself.
Sounds like a new Agatha Christie novel....but with modular systems and M-U-R-D-E-R Guinness ftw!
Graham Hinton
glassofwater wrote:
My first try at a solution was buying an Ebtech hum eliminator and run the whole thing (or trying out seperate modules) through that. Didn't work. TRS-cables or not, no change.

I then got a Furman M-10x E power conditioner and now run my entire room through that (so, the four modular cases, my speakers, my PC (both case and screen) and the previously mentioned mixer). Still, no luck.


It is nothing to do with luck. Trying to use such devices to fix a noise problem is like using homeopathy to fix a broken leg--a complete waste of time and money.

Quote:
Top left case: 861 mA +12V, 455 mA -12V, 0 mA 5V

Bottom left case: 1045 mA +12V, 215 mA -12V, 0 mA 5V

Top right case: 976 mA +12V, 635 mA -12V, 120 mA 5V

Bottom right case: 431 mA +12V, 263 mA -12V, 0 mA 5V


There is your problem. Every case has significantly more positive current than negative and the differences flow into the 0V--a total of 1.865A! This shows that you have a lot of digital modules as pure analogue ones tend to have fairly similar currents on each rail. This also means that there is going to be both a dc and an ac component as there will be a lot of switching going on at different frequencies.

The 0V currents will produce a voltage in the resistance of the 0V wiring by Ohm's Law, V=IR. You cannot change the currents (I) unless you abandon noisy modules, so the only way of reducing the voltages (V) which are getting picked up is to reduce the wiring resistances (R). You have a power distribution problem. Your figures show that you should expect such problems in each case anyway, it is nothing to do with something you have changed.

All the answers to your problem are in the can I use two PSUs in the same rack? thread.

Tonefloat1 wrote:
Whatever you changed and/or rearranged and/or acquired since the ground loop, undo it all in reverse order and the culprit should soon reveal itself.


He is not complaining about a ground loop problem, this is just more homeopathy.
tuj
I had a ground loop problem that was making it to my monitors (but strangely not my interface). The ground loop was even penetrating the UPS for my computer. I could tell it was the computer causing it because I could hear it changing tones as I opened and closed windows/programs.

I solved the problem by plugging the monitors into an isolation box.

Here's the one I used: https://www.amazon.com/gp/product/B07595XJ3N/ref=oh_aui_detailpage_o01 _s00?ie=UTF8&psc=1
Tonefloat01
He is not complaining about a ground loop problem, this is just more homeopathy. HINTON

Listen pal, offering up ways to troubleshoot a problem is not ‘witchcraft’ but a methodical approach to solving a problem. The OP said the problems came out of nowhere and without any further information I offered up a way to start to remove the unknown variables from his system until the noise was removed.
I just offered up some friendly advice to someone in need, that’s all. Did I ask him if he whistled on a Tuesday or crossed a black cat recently? No I think not. Jeesus... Dead Banana
stamppotwortel
You don't happen to have a Beatstep Pro connected do you? That introduced a lot of hum in my set-up when connected. And that issue was solved using the splitter that comes with the BSP
arthurdent
"OK Mr. Wiseguy" she said, "if you're so smart, what color do you think the wheel should be?".
Shledge
Some modules can be susceptible to EM radiation from the switching supply. I've learned this when trying to use a Ladik panner with my PSU3 case - it works fine only when put into the PSU2 case. Never had that issue with any other module, even other Ladik modules.

Haven't had issues with my bitbox with other modules though. Everything is pretty much dead silent.
huffnPuff
Tough to get problems solved when people get entrenched in their egos. If you really want to help someone other else then you must learn to put it aside, if only for one short moment.

Some of the problems mentioned here by other users are obviously related to EMI (hearing your computer doing stuff).

The OP mentiones connecting to a soundcard. If the soundcard works on its own without being connected to a computer then that’s the first thing I’d try. Otherwise I’d hook up the modular directly to the monitors - BUT ONLY IF THE OUTPUT MODULE IS AC COUPLED OR THE (powered?) MONITORS ARE!
glassofwater
Graham Hinton wrote:


Quote:
Top left case: 861 mA +12V, 455 mA -12V, 0 mA 5V

Bottom left case: 1045 mA +12V, 215 mA -12V, 0 mA 5V

Top right case: 976 mA +12V, 635 mA -12V, 120 mA 5V

Bottom right case: 431 mA +12V, 263 mA -12V, 0 mA 5V


There is your problem. Every case has significantly more positive current than negative and the differences flow into the 0V--a total of 1.865A! This shows that you have a lot of digital modules as pure analogue ones tend to have fairly similar currents on each rail. This also means that there is going to be both a dc and an ac component as there will be a lot of switching going on at different frequencies.

The 0V currents will produce a voltage in the resistance of the 0V wiring by Ohm's Law, V=IR. You cannot change the currents (I) unless you abandon noisy modules, so the only way of reducing the voltages (V) which are getting picked up is to reduce the wiring resistances (R). You have a power distribution problem. Your figures show that you should expect such problems in each case anyway, it is nothing to do with something you have changed.

All the answers to your problem are in the can I use two PSUs in the same rack? thread.


Cheers, Graham. I've read that thread now a few times, but seeing as I have no experience with this it's taking me a while to understand it. I'm still not sure what I can physically do with the PSU's I already have? I'm reading your site http://www.hinton-instruments.co.uk/paprod/psu/distribution.htm

As you say, the power distribution is off in all of my cases so let's say I only want to properly distribute the power in one of the cases to begin with. Can I change the busboards in my case with busbars and have them work with the PSU I already have? One busbar per rail, and one common 0V bar where they're all connected?

Thanks for your effort, it's appreciated!
Graham Hinton
glassofwater wrote:
As you say, the power distribution is off in all of my cases so let's say I only want to properly distribute the power in one of the cases to begin with.


Not so much "off" as never designed to cope with that sort of load in the first place. There are two critical places in any distribution system that may cause bleed problems between modules:
1) the main supply cables between the PSU and distribution rails, as these carry the combined currents
2) the 0V wiring between all modules, as too much resistance here causes the modules to have different "0Vs".
Long pcb buscards with ribbon cables aren't the best solution for either when larger currents are involved.

Quote:
Can I change the busboards in my case with busbars and have them work with the PSU I already have?


Yes, with the qualification that a PSU with individual outputs would be better than one with a "COM" output and you may not have a mains Earth available. No distribution system will stop noise created by the PSU, that should be filtered in the PSU before it reaches the distribution, only noises due to modules.

Quote:
One busbar per rail, and one common 0V bar where they're all connected?


Yes. The 0V linking would be done differently depending on if you want your cases to be portable or not.

Please PM me if you want to discuss your particular situation.
glassofwater
Graham Hinton wrote:
Please PM me if you want to discuss your particular situation.


Thanks! I'll do that after my vacation. Dead Banana
pugix
You said, 'Usually everything is going into one of the cases where i have 4 x Doepfer performance mixers.'

If you patch this way again, does the problem go away? If so, then it's something to do with new way of patching, not a sudden problem with power supplies.
glassofwater
Let's take the example with the Bitbox up there.

If I plug my headphones straight to one of the Outs on the Bitbox: no weird sound when loading samples.

If I plug the Bitbox Out to Intellijel uJack, and then my headphones to the uJack it starts happening. (Or Bitbox Out -> Doepfer mixer -> straight to headphones, it happens)

All this without going through PC, soundcard etc.

This is also with everything in the same case, not connecting it to anything else.
pugix
glassofwater wrote:
Let's take the example with the Bitbox up there.

If I plug my headphones straight to one of the Outs on the Bitbox: no weird sound when loading samples.

If I plug the Bitbox Out to Intellijel uJack, and then my headphones to the uJack it starts happening. (Or Bitbox Out -> Doepfer mixer -> straight to headphones, it happens)

All this without going through PC, soundcard etc.

This is also with everything in the same case, not connecting it to anything else.


OK. You can try some of the following to try and isolate the problem. For each of these see if it still happens.

0: Try it with completely different patch cables to rule out a cable malfunction.

1. Remove all other modules except the Bitbox and the uJack from the case.

2. Same thing but only Bitbox and Doepfer mixer.

If the problem goes away, then put back the other modules one at a time until it happens. That module would be suspect.

3. Install a different power supply, or with the Bitbox and the uJack and Doepfer mixer in a different case with a different supply.

Report back.
Tonefloat01
pugix wrote:
glassofwater wrote:
Let's take the example with the Bitbox up there.

If I plug my headphones straight to one of the Outs on the Bitbox: no weird sound when loading samples.

If I plug the Bitbox Out to Intellijel uJack, and then my headphones to the uJack it starts happening. (Or Bitbox Out -> Doepfer mixer -> straight to headphones, it happens)

All this without going through PC, soundcard etc.

This is also with everything in the same case, not connecting it to anything else.


OK. You can try some of the following to try and isolate the problem. For each of these see if it still happens.

0: Try it with completely different patch cables to rule out a cable malfunction.

1. Remove all other modules except the Bitbox and the uJack from the case.

2. Same thing but only Bitbox and Doepfer mixer.

If the problem goes away, then put back the other modules one at a time until it happens. That module would be suspect.

3. Install a different power supply, or with the Bitbox and the uJack and Doepfer mixer in a different case with a different supply.

Report back.


Best tread carefully around these parts with your fancy deductive reasoning...

xenosapien
Just in case you guys missed the memo:

Graham Hinton is ACTUALLY HELPING glassofwater/the OP, who is being thankful and respectful for it.

I´m not saying the rest of you isn´t helping - but if you read through this thread, you can see whose "egos" are in play here, and whose isn´t.

Mr. Hinton surely should never be a diplomat, but come on - it´s not like he is burning people at stakes here. It´s just his way of writing... calm the hell down everyone.

(also, I have the feeling he might be right)
glassofwater
pugix wrote:


2. Same thing but only Bitbox and Doepfer mixer.

If the problem goes away, then put back the other modules one at a time until it happens. That module would be suspect.


Can one module really screw up the rest of the system like that? Afaik all my modules work, but ofc one could be faulty.
glassofwater
Still basking in the terrible warmth of our sun, but I’ll be back home next week.
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