Dwarf Noise (Solved)

Frank_Paul · September 8, 2021, 7:45pm

Hey EW - thanks in advance - very, very much!

Sounds like a science experiment you’re anticipating, or an engineering project, LOL

Seriously, I hope I am not helping to contribute to an onerous task for you. But, needless to say, given your willingness to do all this analysis, I would love to hear your findings. So thanks again.

Interesting that there’s a possible power supply angle to all of this, based on your and @ianr’s posts. I think one thing I can do this end, later today, is just see if one of the after-market AC adaptors I have laying around (assuming it matches the Dwarf’s power requirements of course) could potentially make any difference when plugged in. The thing that’s so weird in all this, is that by themselves, my Dwarf and my Focusrite/PC/Ableton chains seem to work fine; it’s only when I combine all of the above that I run into difficulties. If it’s a power supply issue in that scenario, then I would need to read Electrical Engineering for Dummies to begin to understand how/why

Incidentally, I decided during my bass practice session yesterday to just work the Dwarf by itself and not even bother with Ableton, and I must say I had a lot more fun with it. Volume fine, noise levels negligible. I even set up a new “clean bass practice” pedalboard on the fly including minimal compression and reverb (no EQ, I’m still pretty partial to my Darkglass bass preamp stomp for that) paired with the looper pedal and metronome plugins. Was having fun jamming with myself in no time. I then modified the looper into a switchable drone track that I could feed a signal from my Gamechanger PLUS sustain pedal into, using CV modulation to vary chorus and phaser depth and rate settings and it got crazy cool, over-the-top weird, which I enjoyed. So I am still very much digging the Dwarf. Shall we call him Gimli perhaps?

Anyways - if there is anything at all I can do to help in the effort to discover and route out the connectivity gremlins, let me know!

Cheers
Frank

Frank_Paul · September 8, 2021, 7:53pm

Elk_wrath · September 8, 2021, 8:02pm

Hey Frank!

Definitely going to be conducting this as a scientific study, only way to confirm a hypothesis is with peer review!

I’m very interested in the results of your testing with a regulated power supply, if several of us have the same results then we can confidently suggest a solution, so please post your findings!

It’s looking more like tomorrow might be the best day for me to commit some time for testing and I’ll try my best!

This is zero issue for me to experiment, I don’t have commitments, a goal, or a unique sound, so any time spent on this issue is a net positive to me down the road.

I’m hoping we can isolate and fix this issue together!

I’m glad you found a successful workflow in the mean time while we continue to experiment with this issue!

Hope all is well,
-Elg

Frank_Paul · September 8, 2021, 10:13pm

Rats, so much for that idea. I have four other power adaptors lying around, but they’re all 9V, not the 12V the Dwarf needs. So unfortunately I can’t see what might happen (if anything) using a substitute power supply. Oh well…

Elk_wrath · September 8, 2021, 10:35pm

Well my power supply package was delayed until tomorrow, sounds like it’ll be a good day for me to test when I get everything in.

Unfortunately I probably won’t be in the condition to test anything until next week, but I’m still gonna try to play.

I’ll post as soon as I can test!

Hope you’re doing well, Frank!

Frank_Paul · September 9, 2021, 12:10am

Thanks EW, and please, no rush! I will owe you my debt of gratitude if we can figure this out and resolve it. I might have to send you a digital beer, LOL

ianr · September 9, 2021, 7:48am

One super quick test you could do is to simply unplug the Dwarf supply from the mains and listen to the effect.
When I was experimenting I discovered that there’s enough capacity in the Dwarf power supply to keep it going for a few seconds (2 or 3) before it cuts out. As you unplug it from the mains it no longer has that connection to earth and so you should find the noise disappears before it cuts out.

jon · September 9, 2021, 2:08pm

I’m not sure. I tend to use on my setups the Dwarf going to a Presonus soundcard into Ableton (I’m not using the instrument inputs on the Presonus) and it works just fine. I also already recorded it this way and had no problem (also with the Dwarf connected to another soundcard and a friend’s computer running Ableton).
It really seems weird your problem.
Do you have any way to try the setup on a laptop?

Frank_Paul · September 9, 2021, 10:12pm

Hi ianr

Thanks for that suggestion. I did give it a try and found that, for whatever reason, my unit did not behave the same as yours: on unplugging the power supply, there was no lingering audio signal for 2-3 seconds on mine and thus I couldn’t try the test that you suggested. Maybe if you’re not located in North America (like I am), the power works slightly differently where you are (?).

Anyways, I’m gonna keep crossing my fingers that replacing the USB cable connection to the PC with a bluetooth dongle might, somehow, have some effect. Will report back here on that (next week).

Cheers
Frank

Frank_Paul · September 9, 2021, 10:22pm

Thanks for that advice, Jon. If you don’t mind me prying further, I’m trying to visualize what you mean by plugging directly into the Presonus sound card. Is the Presonus unit you’re using a regular desktop box of some kind? if you don’t plug into the instrument inputs, how do you get your signal into the sound card?

On a related note, I had this exchange with tech support from Focusrite, and I don’t imagine there would be any sensitivity to me sharing it, in case anyone else here might find it of interest:

My original message to Focusrite:
Frank Paul

7 Sep 2021, 17:31 BST

Hello. I don’t know that there is an issue with my Focusrite 2i2 specifically, but I don’t know whom else to ask for support and am hoping you might be able to help me.

My Focusrite unit works fine when in my “normal” configuration but I have an issue in one specific use case. I own a multi-effects unit called the MOD Dwarf (MOD Dwarf – MOD Devices) and I find that when I connect the Dwarf to the Focusrite (via single TRS cable; note the Dwarf is connected to the same PC that the 2i2 is connected to, also via USB) and connect my headphones into the headphone jack of the Focusrite, I get very noticeable audio hum and this noise is picked up also when I record the signal that I’m sending from the Focusrite to my PC using Ableton Live 10 as my DAW.

By contrast, when I either disconnect my headphones from the 2i2’s headphone jack and plug them into the headphone jack of the Dwarf instead, i.e. when I use the Dwarf in standalone mode without connection to the 2i2, the noise disappears almost entirely. Alternatively, using the 2i2 without connection to the Dwarf (i.e. plug my bass guitar directly into the interface), I don’t experience this issue and my signal chain works fine as usual.

Why all of this is a problem for me is that it feels like I can’t use the Dwarf in combination with the 2i2 to feed a post-effects instrument line signal into Ableton Live and get quality audio. I can only use the two devices separately from one another, which defeats the purpose.

I assume that there must be some kind of ground loop issue coming to bear here, and yet I don’t know how to resolve it beyond what I’ve already done, which is to make sure that the effects unit and the PC (which the Focusrite is connected to vis USB) are both connected to the same wall outlet for power, which they are.

Are there any steps you can recommend to me which might help eliminate the hum I’m hearing via my headphones when the effect unit is connected to the 2i2?

Thanks in advance for any help you can provide.

Kind Regards
Frank Paul

Reply from Focusrite:

Hi Frank,

Thanks for getting in touch.

You’re quite right, the issue will almost certainly be to do with a grounding problem.

First, please ensure that your interface is connected directly to your PC, testing every USB port, and not through a USB hub or any other device. If you have any monitor speakers connected to your interface please disconnect these and see if there is any change.

If you are able to do so, try swapping out the TRS cables you’re using to see if they are in any way damaged or defective.

It’s also possible that your PC could be the culprit - In the past I had a similar issue where the graphics card in my PC was the source of the interference.
You can narrow things down by testing your interface with a battery powered laptop: If the hum is gone, you know the issue is something to do with your PC, If the hum persists you can look towards the other links in the chain.

Hopefully this is helpful to you, Frank.

Please let me know if you have any questions or if there is anything else I can help with.

Best Regards,

ianr · September 9, 2021, 10:44pm

Thanks for giving it a go Frank_Paul - it does sounds like your power supply might behave differently to mine, but just to check…you need to keep the power supply plugged into the Dwarf, just disconnect the feed from the wall - is that what you did?

All the best,

Ian

Elk_wrath · September 10, 2021, 2:04am

Frank I am in the same boat as you.

I tried both the new mixer power cable, as well as a new PSU for the dwarf, new PSU made things worse on my end. I reverted to my normal set up with the new mixer cable.

I’m starting to question my audio interface. The noise is mostly gone, and I put a filter on the master channel of my mixer to kill the high frequency noise, but it’s still there.

I’ve pulled the recorded file from both my mixer SD card, and through AUM. Listened to both raw, and normalized.

Nothing I have done can kill this last hiss, and it’s present in both recordings.

So I’m betting I’m fighting a ground loop.

I can’t mess with any of my gain stuff anymore because if I do, I’ll lose the majority of my volume.

Since I need to rearrange my set up to work with this monster 2600 clone, I will just tear everything down and start over again.

This thing is a lot of fun, but it’s not exactly table friendly….

Thinking about it more, my big poly synths are plugged into a different outlet than the rest of my gear, and I’m wondering if it really a ground loop I’m hearing.

I won’t be able to test anything for a couple of days, but I’m gonna move stuff around and test it this week.

Frank_Paul · September 11, 2021, 7:38pm

Hey EW - thanks for sharing, again. (Btw, that is a mighty impressive looking workstation setup you have going there. I’m not super knowledgeable about synths so I couldn’t tell what kind you have, but it sure does look like a nice piece of kit! )

Anyways, interesting to hear about your latest findings, and that these are leading you to a possible conclusion of ground loop problems. I have to say, that despite my lack of technical skills or sleuthing ability, I’m kind of wondering the same thing for my setup. It was only when I started to deliberately use the Dwarf in standalone mode that I realized its overall sound quality was actually way better than I initially thought while sending its signal through Ableton. Somehow, the combination of my interface and Ableton has been coloring my Dwarf signal in ways that are not desirable. In the Dwarf (standalone), I can work with a dead simple rig including nothing more than simple compressor, frequency crossover and simple reverb and it frankly sounds a lot closer to my ideal bass tone than anything I’ve been able to cobble together in Ableton to date. So there’s not only the ground loop issue, which persists for me, but also the fact that the signal Ableton takes from Dwarf ends up sounding diminished and unhappily colored somehow. Maybe, just maybe, Ableton is a DAW that is more appropriate for electronic music producers than it is for guys like me who want to plug in an electric guitar instrument to record it cleanly and faithully to the line level sigal, whether wetter or dryer (?).

I’ve decided to sign up for a free 30-day demo trial of Presonus Studio and see if I getter different results. I also hope - fingers crossed - that when my bluetooth dongle comes next week I might hear a reduction in the possible ground loop hum by bypassing the physical USB connection of Dwarf to PC, which is what the interface is also plugged into. We’ll see.

Did I ever ask you what type of interface you’re using? If we get similar issues using different interfaces, then I suppose the possibility that all of this is the interface’s fault might be less likely.

Anyways, thanks for keeping the discussion going; I hope we can finally nail this issue down fully.

Cheers
Frank

Elk_wrath · September 11, 2021, 8:10pm

Hey Frank,

So I’m still plugging away at this issue today.

I’ve made sure to connect all of my gear into one outlet and the noise persists.

I’ve addressed my mixer and messed with its compressor settings, no luck (other than sound quality improvement) with eliminating the hiss.

I’ve attempted to apply high cut shelf’s to the master track, filters, anything, and to no avail.

The audio is definitely sounding a lot more crisp though: Dropbox - Noise test.wav - Simplify your life

You can hear that hiss still when it should be quiet.

I will let you know that this hiss persists whether the dwarf is powered or not.

My mixer shows dead silence, and so does my iPad.

I’ve tinkered with everything my limited working know how can accomplish at the moment.

Since I’m stumped but pretty happy with the progress made on the noise issue (you can hear the audio difference listening to my Mod dwarf track versus anything I’ve uploaded since that track) I’ve started working on building my second set up for video demonstrations.

I’m digging the camera view so far:

In terms of my audio interface, I’m using a behringer Uphoria UMC 404HD.

However, I swapped that out with my steinberg UR22mkII and saw no improvements to the noise.

I’m really stumped because I have a bunch of gear in my set up, but nothing USB powered at all at this time. Everything has its own wall wart hooked into my power conditioners.

At this point I’m considering finding an app that removes noise from recordings and go from there.

Either way, I’ve had massive amounts of improvements to the fidelity of my recordings and I’m pretty close to just forgiving the hiss and moving forward.

I have a hard time letting go of a problem if I know there is a solution out there somewhere, so although I want to say I’m happy with my situation, the truth is that I’ll always be trying to figure out how to solve this problem lol

Edit:

So I’ve been thinking about my house wiring. I have both city grid and solar panels powering my house. I’m going to install a 1000W medical grade isolation transformer with 4 outlets into my set up and run four 6 outlet power conditioners from there to power my entire set up off of one electrical outlet and see if it’s my house wiring causing the issue. Either way, that should eliminate any chance of a ground loop.

It’s not the dwarf making this noise in my case, there is something else causing it. I pulled the dwarf out completely and the noise is still there.

danmh · September 11, 2021, 11:02pm

Hey if you want a spoiler of this you can just unplug the usb from your dwarf now.

Even though you need a connection to the computer to edit patches, once they are set up you don’t need to maintain that connection — so you are free to test even before your dongle arrives

ianr · September 12, 2021, 1:03am

Hi Guys, sorry to hear that the power supply change didn’t help you.
I’ve just read through the whole thread in more detail (only had the chance to skim it before - an interesting read!) and listened to the audio sample you posted Elk_wrath.

I realised I should’ve been clearer about the noise I was getting, which the change of PSU helped fix, since it seems like there might be multiple things going on.

The sound I had was a kind of high frequency warble - not one stable sound, and this was fixed by the change of power supply (or removing the earth connection to the original supply).
Hiss was mentioned (and I could hear a small amount in the audio sample). That can be exacerbated by bad gain-staging (where you cut the signal too much in one part of your setup so you then have to boost it later on to compensate, and in the process you boost the unwanted interference too). Cheaper mixer pre-amps add to the problem.
Hum (low frequency - 50Hz in the UK or 60Hz US) was also mentioned, and I could hear that in the audio sample as the most noticeable interference (for my old ears anyway!). That can be caused by an earth loop (fixable by a ground-lift), or bad/wrong cables, or bad gain staging. It can also happen if you have a power supply sat too near your devices or their cables, so definitely worth making sure you keep them as far apart as you can. Again cheaper/faulty gear may not have such a well regulated power supply, so hum creeps in.

If you’re only running good quality cables over short distances you really shouldn’t need to worry about having to send balanced signals - unbalanced should be fine.

Gain staging is very often the problem though, so when you’re experimenting with your setup it’s worth making sure that the signal is about the same level the whole way through your chain, not reduced at one point, then boosted up again. If your audio interface has a line/mic switch it should be switched to line-level (maybe this is what you were using the pad for?).

Hope some of that might be of help.

Ian

Elk_wrath · September 12, 2021, 1:18am

Hey @ianr!

Thanks for checking back in, it sounds like we indeed have different noise issues.

Now I did spend pretty much my entire day working on gain settings with each device, and my audio is much clearer than it ever has been before, very exciting in fact. Even before, I did try to work on my mixing, but I was never able to get suitable volume until changed cable types connecting my mixer to interface.

On my old Yamaha mixer, I didn’t have as many of these issues to begin with. I’ve brought that mixer back into my secondary set up and I’ll be working on integrating them both into one recording set up later today.

I made a few changes, but the one that helped the most for some reason was changing from TRS to TRS cable to a TRS to Stereo XLR breakout from my mixer to audio interface, the audio quality improved immediately. The volume difference was so great after the cable replacement, that I was actually able to start addressing my gain settings in my mixer and get proper clean levels.

Another thing on my mixer is that it’s compressor was also contributing a bit, so I adjusted that.

Now the audio is almost crystal clear except for the hum.

I made an edit to my last post regarding the way my house is powered.

I am on city grid with the majority of my power coming from my solar panels. I am not sure exactly how that affects my situation, but due to the year my house was built, I am not confident in my electrical situation.

That being said, I ordered a 1000W medical isolation transformer for my entire audio rig. This is my last ditch attempt to rectify the issue.

Even if I turn the gain to -96db on all inputs, and volume to -96db on all inputs, the hum remains.

So I’m really hoping that it is indeed my particular house power set up being the issue and this transformer will kill the hum.

Worst case, I send it back lol

Frank_Paul · September 12, 2021, 5:09pm

Hey EW

Re: audio file - nice! You got a cool Blade Runner vibe going there. I did notice what you mentioned, though, the hum in the first few seconds before your synth kicks in. Mine in the setup using the interface to PC sounds very similar, although probably relatively louder still, since, with an extended range bass, I can only decrement gain stages so far before the thing sounds gutted and too quiet. Interesting that there might be an app to remove the hiss; maybe Izotope’s Ozone product or something like that? For me, I need a solution that resolves all of this before I get to a recorded track; I just hate hearing that noise even while I’m headphone monitoring without recording.

/fp

Frank_Paul · September 12, 2021, 5:14pm

Hey Dan - thanks for the spoiler! However, I don’t quite follow you, because anytime I pull the USB cable to my PC while using the Dwarf I get that standard error message about “can’t reach that page” and only by plugging back in is the pedalboard local site restored. Or do you mean simply to use the pedal completely in standalone mode, as if I was taking it to a gig or something? I mean, yeah, I should give that a try too, but even if there is a difference, since I spend so much time in patch editing mode and/or wanting to record to Ableton, I would still need to hope the dongle works, or there’s some other solution. Will report back here if anything new this end.

Cheers
/fp

danmh · September 12, 2021, 5:26pm

Hey FP

Yeah this is what I was thinking, completely stand alone it will let you know what affect (if any) the usb connection is having. And clues as to if the dongle will make a difference!