I wholeheartedly support your solution for the reasons I have stated above. In some countries and/or in places whose electrical installation is somewhat old (very common here in Europe), at times the shield of the TRS cable alone may not withstand a load in the neutral side of the electrical connection in the event, for instance, of an electrical discharge. Also, leakage breakers (RCD in the UK, GFI in the US, or “leakage interrupter” more generally speaking) do not provide protection in the event of a live/phase to neutral short. So one should always have a good and high-capacity connection to ground at all times.
I’ve had the Dwarf for a week or so and have been battling this. I’m pretty sure (like many have mentioned) that it is a ground loop issue.
I get the noise in the following setup:
Dwarf output 1 -> Amp. (nothing plugged into input, no plugins connected on the dwarf)
The Dwarf and my amp are plugged into the same power strip.
Headphones sound clean.
I tried another 12v 2a power supply without a ground pin and it sounds crystal clear - I realize this isn’t recommended.
So this seems pretty squarely a ground loop issue. I’ve never dealt with this before - I guess none of my previous pedals have had grounds.
So my understanding now is that I either need a direct box with a ground lift.
My question now is - do most direct boxes lift the ground on the amp pass-through or only on the XLR cable? Does anyone have a recommendation on a reasonable and small-ish direct box that will remove the hum and still let me play through an amp?
The DI Box per se has the purpose of connecting an unbalanced, high-impedance signal of a guitar/bass and convert it into a balanced, low-impedance signal for the purpose of connecting such instruments directly to the mixer or power amp of a studio/venue – hence the name Direct Injection box. Over time, some features were added to them, such as a switch for lifting ground.
The better ones will however have an audio isolation transformer which fully isolates both ends of the audio line, therefore removing the hum from the audio without doing anything to the electrical connection of the equipment being used. The latter is to me the best of all solutions – I’m not sure what @perroud is using, but from the Atelier der Tonkunst website it looks like they employ audio transformers.) UPDATE: @perroud describes that below.
DI Boxes can get nasty expansive, so before jumping into one such solution, you may wish to try some troubleshooting by yourself. For instance, at home I solved the problem by simply connecting all equipment to the same power outlet and have them be in symmetry with each other. Then, I also tested the plug to find where the neutral and phase/live actually were – in some countries like Italy the power plug is fully symmetrical, so you can’t tell one from the other. This is not a problem in the US (though electricians may connect those cables in reverse order, so one may need to test it there as well.)
If none of these work and if you’re not comfortable simply lifting the ground, then look for a smaller and much cheaper device for simply filtering the ‘hum’. I saw one Lehle box for less than 40 Euros a while back. A good DI Box will cost half of the price of the Dwarf, so unless you really need a DI box for what it is, don’t buy one.
(I myself had a hand-built DI box in the past that had the best of all worlds: it converted impedance, had a full bypass for the amp, and had an audio isolator within it. Maybe I should resume producing some of those…)
Hi there,
I sbsolutely agree with @jeffutter. I had this insane high-end DI box lying around (it is very expensive, 178 Euros, it is a passive box with a ground lift) so I didn’t bother to search for other solutions. I indeed first tried to have all the equipment plugged in the same power outlet but without success. When I plugged in the usb cable to the computer I had a bit less of a hum, but still very noticeable. The Di Box is very small, I have it attached with velcro directly onto my Mark bass amplifier and connected with a short xlr to jack (symmetrical) cable. I’m very happy with this solution!
Which DI can you recommend?
I am thinking of buying a Radial Engineering J 48 Stereo; USER GUIDE “Frequency response: 20Hz ~ 20KHz; Dynamic range: 109dB”. Does that make sense? Only that the 48V phantom power needed, alternatively with power supply or battery would be more flexible. Radial Engineering J+4; USER GUIDE?
What do you have in use?
Funny thing about DI-box. I was using behringer DI20. Somehow it is eliminated noise, but there is LED indicator blinking when it is turned ON, and I can hear now pulse noise of this LED light. Weird.
okay, I’ve never used them before, I always believed that a balanced cable had to be xlr both ends, didn’t realise you could use xlr to stereo 1/4 inch jack as well!
the other guitarist in our band used to use a pair of Palmer PLI-01 Line isolators. They have an in and output resistance of 10 kOhm and isolated ground (no ground lift) through the audio transformer.
It may be important to look for impedances of your other equipment, otherwise you may be losing gain.
The 2-channel SB-06 Stagebug by Radial Engineering is similar, but it has a ground lift per channel as well as a polarity switch on the left channel and a 15dB pad.
Hope that helps. Maybe someone with greater wisdom might chime in.
Thank you very much, the exchange among each other is always helpful.
I think there are many different experiences/situations/combinations of how to use the ModDevice.
A friend of mine, he is among other things an electronics engineer who invents / builds audiophile DIY instruments, wants to look at the duox times in the foreseeable future and tinker what. As soon as he has found a good solution I will report here.
EDIT:
Just from him get informed that this would be the appropriate component: Monacor LTR-110. More info will follow and whether that brings the desired success in practice.
Just wanted to update here. The main source of my noise was 100% a ground loop. Using a balanced cable between the dwarf and my amp (Henricksen Bud) fixed almost all of the noise. There is still a slight bit of electrical interference noise at times - I need to try removing the usb WiFi adapter to see if that cleans it up. Either way it’s much improved.
The remaining noise is very “digital” sounding. I’ve made the following observations:
Guitar -> Amp: Silent
Dwarf -> Amp: (balanced cable, empty pedalboard, no fx loaded and no patches not even input patched to output): slight noise
Dwarf -> Amp: (balanced cable, pedalboard loaded, final volume set to 0): noise 2-3x louder - still way less than ground hum.
Seems like it might be interference from the CPU since it’s louder with a full board?
If a real balanced cable is required between Dwarf and amp, it will be the first guitar pedal I will use (still waiting my kick-backer time to come ???) which will need a balanced link, and I would say that none of my tube or digital amps accepts balanced input ??? Using balanced input will divide the signal strength …
I’m sorry to say that I got excited and jumped the gun a bit. The noise is the same on the dwarf with a balanced and unbalanced cable. It is definitely less noticeable with an empty pedalboard, but with a loaded board it is the same regardless of which cable I use.
I assume my amp knows how to handle balanced cables since the jacks are combo XLR & 1/4” jacks.
I have a bass DI box I can try putting between the dwarf and the amp. I’m hoping that this isn’t the ultimate solution - it would be pretty pricey particularly if running both channels on the dwarf.
Since the main thread here is [solved] I’m wondering if I should start a new Dwarf-specific thread for this? If so is there a troubleshooting sequence I should go through (different combinations of setups) to try in-order to provide a full picture of my issue?
Update: I tried a few configurations with the DI box (EBS Microbass II). All tests had nothing plugged into line in on Dwarf.
Fortunately my guitar amp has XLR input, my bass amps do not. So far I’m unable to get a clean sound out of my amps that take 1/4 input. This is disappointing.
This is some progress… although requiring a DI box with a ground lift and an amp that takes XLR is pretty specific. Are there some people out there running their Mod Devices gear direct into amps via 1/4”? It sounds like there are, maybe this issue is specific to the Dwarf?
I would say that for now is fine to keep the conversation here. But if you feel that the subject is not related anymore, go ahead and start a new thread.
As an overall answer, I can tell you that a new update to be released soon will bring a loooooot of improvements on the overall sound of the device with a system noise gate on the input and compressor on the output. I tried it myself already and the sound quality of the device got a really nice improvement (although I never faced big noise issue with the unit that I have on my setups).
Yes, we are even preparing a blog post about that and some documentation that should go into the wiki (although the last one is on me and I must say that is a bit late).
If you already tried the balanced cables and the DI, I would suggest you now check what I told you before about the USB (if you don’t have it connected you will have one less source of potential problems). After that, double-check you gain staging on the device settings.
Do the typical:
on the input, try to increase the gain on the device connected to the MOD Dwarf and decrease it on the Dwarf
on the output, increase the output gain of the Dwarf and decrease on the device where you have it connected.