Hum, digital noise

Ok, thanks!

If I switch to the internal ER regulator, I get even more dirty noise…

Not sure if someone mentioned this, but the Meng Qi Please Exist 2 can take ground hum away with the ground lift switch. Not to mention overdriving it becomes dreamy.

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Before anyone gets too excited and buys a PE2 to solve their noise issue, I want to point out that ground lift switches are meant to address an entirely different type of noise than discussed here. The issue at hand is conducted noise at the power supply where the source of the noise is high-frequency, high-current load from digital modules. Ground lift switches are a kludge typically used to reduce mains frequency hum from ground loops outside your system (e.g. when your system and the PA are plugged in across the room from each other).

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I’m going to order some TDK PN: ZCAT3618-2630D-BK and see if the choke helps mitigate any power supply noise (if that is even the cause).

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Great idea, please let use know if that works. I’ve ordered two of these Noise killer plug for eurorack power but it will only be shipped after 25th, so I can’t report any sooner.

Does this snap onto the bus cable or something? What does it do exactly? I can’t find a description on any of the sites that sells them!

I think I’m going to get a couple of his bus boards too, just for the 301’s. From the description, it sounds as if that’s also a factor. I’ll send him an email before I order, and maybe get him to have a look at this thread too if he’s up for it. I’m waiting for him to get back as well! :grin:

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I received the TDK chokes and tested them out last night. They work well but some noise is still audible with the interface’s gain cranked. My measurements indicate a 6.8dB drop in the digital noise.

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Have these arrived with you? Curious if it works!

I apologize for the delayed response. The Noise Killer Plug has arrived and had a really quick test with them with my Intellijel 104HP case. Unfortunately no improvement, noise floor and behaviour is the same as I reported above… I’m planning to order some ferite chokes and try them out but my expectations are reserved.

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Well. After 2 years of tests, I give up.

  • I tried like 7 different cases. With Monorocket, 4MS, Pulpologic powers. With ADDAC, Pulplogic, Circuit Abbey outputs.
  • I tested a friend’s unit at his place 400 km from my place : same digital/screen noise through the speakers.
  • I tested the TDK chokes.

There’s something really strange about it. I’ve got absolutely no doubt that the noise produced by my friend’s unit and mine are really noticeable.
As much as I love the ER-301, it’s just impossible to use on stage with this issue.
I’d sell it, but I feel uncomfortable with it.

Here is a commented recording of my ER-301 noises.
It’s the only module in the case, using a 4MS Row Power 40. Plugged directly to my soundcard.
Also, it’s hard to notice, but I can hear the noises “acoustically” as well, when it’s not connected to the loudspeakers. It’s very quiet but definitely here, and seems to come from the main screen.
/original/2X/7/7d2cfd3e0fe2fb56d1ba2c1eb033d22a9c837e18.mp3

You are welcome to send it to me for analysis/repair. I think I offered you the same awhile ago? :thinking:

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I’ve also noticed that kind of noise recently (due to the screen) but with the appropriate gain stage they tend to disappear. I know you’ve tried every possible gain staging @chapelierfou but I’m sharing my experience as well. Each setup is different, in my case I noticed that using the Eurorack and the 301 with external sound sources tends to make thing worse or emphasize some noise issues :sweat:

I’m using the Er-301 with an Octatrack and an ES-8. Various sound sources in the rack are routed to the Octa through the 301. The Octa goes through a very clean Strymon rig and then goes back to the 301. Then it goes to the ES-8 or other audio interfaces (by the way I noticed a slight amelioration using TRS shielded cables between the 301 and the audio interfaces but that’s minor). The 301 preamps are set to line level. That’s a lot of gain changes and a potential ground loop (?), at the same occasion I noticed the digital noise that you can hear when switching from admin view or scope to regular view for example, Hermod also introduces a similar noise in the rack. I partially solved that by setting the appropriate gain stage between the octatrack and the Eurorack.

The 301 is not really noisy on its own… as long as I don’t connect an audio input or even activate any of its inputs as an audio source. If I do, there’s a hiss + hum, and it’s multiplied according to the number of audio inputs used. That’s my nightmare now but this hum noise is present everywhere in the rack (intellijel 7u with their most powerful PSU) so the 301 is apparently impacted too and is not particularly responsible for that (not talking about the digital noise here), the noise is particularly noticeable in the analog filters of the rack. If no sound sources are patched to the 301 (hardware synths or even other euro modules present in the same case), if the 301 is the only sound source it’s almost and impressively quiet when patched to the Octa. That means I can still use it as a sample player for example.

I’ve ordered two small NKP (mentioned in this thread) from Poland, I’ll put one of the 301 as a test. I’m kind of gutted because I spent so much on this Eurorack system but it’s too noisy to be used :sob: I wish someone would come up with a really clean PSU solution, something like Strymon Zuma that instantly solved all the noise issues I was having with my effects pedals :slight_smile: I’m powering the Intellijel via a simple Furman but that doesn’t really clean the power, not at all, only protection afaik) I know that the electrical installation in the house is potentially a source of problem too but I spent enough already haha…

I’m seriously thinking about selling all my euro modules and case only because of these noise issues but I would seriously miss the 301 and the great Twin Peaks filter.

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I also get high frequency noise similar to what I hear in your recording especially when changing to admin and back to user mode. I have not noticed any lower frequency noise or hum, thankfully. So for the high frequency noise I just use a lowpass filter unit at the end of the main stereo out chain and adjust it so that it reduces/eliminates the noise. Doing this does not seem to cut away too much of the high end of my music, though I’m sure it does a little. For me this works just fine and sound good.

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FWIW, I haven’t noted any improvement with the NKP A033FA55-94F7-448B-AC0D-5012485F8396

The board of the Intellijel 7U might be already equipped with some capacitors like these so this has no particular/additional effect in my case.

(Tried to put on on the 301, another one on Hermod, also tried to put one on the sound sources of the rack, analog or digital)

I haven’t noticed any improvement either with the NKP plugs. Have you tried these power cables? Premium Eurorack Power Cables - Modular Addict Synth-DIY I’m planning on building them myself.

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No, I have not tried them yet, I’ll have a closer look at these tomorrow. I’m rearranging my Intellijel 7u case, I’ve put the Er-301 as far as possible from the PSU block (the upper row) I don’t know yet if it’s going to improve anything but anything’s worth trying :slight_smile:

Edit: I’ve noticed a significant improvement moving the Er301 to the upper row of the 7u case, as far as possible from the PSU.

I have Intellijel 7u case and ER301 in it. No hum/noise.
I think that position of the module in case can help only in case if some power slots are broken.
The PSU is external (black brick) and only bus board.

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