2 Questions about Micro Station BT and Behringer HD400

[Sebastian Holtzer]

1. Should the Behringer HD400 plugged before or better after the Micro Station BT?
2. For me it makes no sense that pressing the Mute Button on the Micro Station BT will even mute the Headphones. Would`nt it be much more comfortable the other way around or having at least a switch or a second mute Button? Why is it that way? I don`t understand the concept behind it.

 

[Trucky]

1. Should the Behringer HD400 plugged before or better after the Micro Station BT?

The HD400 is a hum and noise eliminator.
Are you having a hum or noise problem?
Is there a ground loop or some other device causing this issue?

 

[Trucky]

2. For me it makes no sense that pressing the Mute Button on the Micro Station BT will even mute the Headphones. Wouldn't it be much more comfortable the other way around or having at least a switch or a second mute Button? Why is it that way? I don`t understand the concept behind it.

I don't have a MicroStation BT but I agree with you...

Per the manual...

The "Mute" button mutes all outputs.
The "Sub Bypass" button only mutes the Sub Outs.
The "Main Out On/Off" switch enables/disables the Main and Sub Outs.

As a workaround, have you tried using the switch to just use Aux Out/Headphones?

 

[Sebastian Holtzer]

Yes, i hear mouse (wired) movements and i read the HD400 kills them. I guess it should before the MSBT or is it better after?

Yes I`m using the Headphones Output, but for me it makes no sense using the On/Off Switch at the Backend of the Device to turn off the Monitors cause the Mute-Button sadly mutes all Output Channels. It seems like a good concept that hasn't been fully thought through. I tried some workarounds with the Outputs on the Listen Bus using the Aux/Input but hav`nt found a solution cause the BT Main-Output get´s feeded then. Maybe I am overlooking something?

 

[Trucky]

Yes, i hear mouse (wired) movements and i read the HD400 kills them. I guess it should before the MSBT or is it better after?

Try it both ways to see which one is better.

Yes I`m using the Headphones Output, but for me it makes no sense using the On/Off Switch at the Backend of the Device to turn off the Monitors cause the Mute-Button sadly mutes all Output Channels.

I don't have the MSBT but I'm interested in knowing if (as a workaround) using the On/Off switch turns off the monitors and sub but still provides audio to the headphones?

Have you submitted a support ticket (see link in my signature) for this yet?
If not, I'd recommend it so it gets logged as an issue...

 

[Sebastian Holtzer]

Try it both ways to see which one is better.

I don't have the MSBT but I'm interested in knowing if (as a workaround) using the On/Off switch turns off the monitors and sub but still provides audio to the headphones?

Have you submitted a support ticket (see link in my signature) for this yet?
If not, I'd recommend it so it gets logged as an issue...

Hey Trucky that`s a good idea. Will test this out in the coming Days and give you feedback, but first i need to get an Adapter. For me this won`t be a lifelong solution cause i was planning to buy a Subwoofer and cause of this the Microstation seemed to be the perfect solution.

I´ve have registered it, but there was no Software for it and i found no App for updating it per Bluetooth. So you mean they will log it as an Product-Design Issue, or is there any software for it?

Edit:
OK checked. I had an Adapter here. It only plays the left Channel but later, after switching a few buttons it was getting quite. Can`t reproduce this behaviour but overall the Device works fine.

 

[Trucky]

So you mean they will log it as an Product-Design Issue, or is there any software for it?

Yes, that helps to make the product developers aware of customer complaints regarding design issues.
Plus, support may have some workaround suggestions.

 

[Sebastian Holtzer]

OK will do that. Thank you.

 

[SwitchBack]

Don't use hum destroyers in speaker/headphone lines. They will only cause signal distortion and won't remove any hum. You may even destroy the hum destroyer itself as they can handle only a limited amount of power.

Hum destroyers are typically designed for line (level&impedance) connections, to lift ground and solve balanced/unbalanced issues. The best position very much depends on the type of output and input on the gear it connects to, especially wrt. balanced/unbalanced.

 

[Sebastian Holtzer]

Don't use hum destroyers in speaker/headphone lines. They will only cause signal distortion and won't remove any hum. You may even destroy the hum destroyer as they can handle only a limited amount of power.

Hum destroyers are typically designed for line (level&impedance) connections, to lift ground and solve balanced/unbalanced issues. The best position very much depends on the type of outputs and inputs on the gear it connects to, especially wrt. balanced/unbalanced.

OK, i`ve got an ESI Maya 44ex PCIe Card with Line-Outs (6,3mm). You mean i should not put the Behringer behind the Line-Outs of the PCIe Card (exactly between the PCIe-Card and the Microstation)? And of course not behind the Microstation (exactly between the Microstation and the Speakers)?

 

[Sebastian Holtzer]

Don't use hum destroyers in speaker/headphone lines. They will only cause signal distortion and won't remove any hum. You may even destroy the hum destroyer itself as they can handle only a limited amount of power.

Hum destroyers are typically designed for line (level&impedance) connections, to lift ground and solve balanced/unbalanced issues. The best position very much depends on the type of output and input on the gear it connects to, especially wrt. balanced/unbalanced.

OK seems like the ifi GND Defender would be a better solution but before I`m gonna buy i`ll will try this one first:

Amazon.de

 

[Sebastian Holtzer]

Try it both ways to see which one is better.

I don't have the MSBT but I'm interested in knowing if (as a workaround) using the On/Off switch turns off the monitors and sub but still provides audio to the headphones?

Have you submitted a support ticket (see link in my signature) for this yet?
If not, I'd recommend it so it gets logged as an issue...

Back again here. I can't recommend Behringer HD400. It only reduces the noise, but you can still hear it.
So I bought the ifi Ground Defender and everything is clean now, really love that. The Only Problem I have now is that I bought the Eris Sub8 BT. Everything (PC, Gear and so on) is connected to a Brennstuhl power socket.
Both Monitors and the Sub are connected with a separate iFi GND Defender (I had to buy 3 GND Defenders).
But the Sub has a very quiet hum. You can only hear it when it's not playing, and you're close with your ears to the sub. Is this normal, or do I have to buy an iFi DC Blocker+ now?

Overall I'm happy with the Sub 8BT and the Eris Studio 5. I had a real Problem with my Subbass and the overall Mix, cause I had to work under Headphones for years now and can now a bit louder here in my apartment.

---

iFi GND Defender:

Amazon.de

iFi DC Blocker+:

Amazon.de

Brennenstuhl-Premium-Line-Steckdosenleiste:

Amazon.de

 

[brmichael]

I can strongly recommend the Behringer HD400. It does exactly what it is supposed to do: remove hum caused by a ground loop.

However, it can't remove hum that has other causes than a ground loop. So if there still is noise even with the HD400 inserted, this noise must have other causes such as magnetic or electric fields leaking into audio circuits. As you have a PCIe card audio interface sitting inside your PC, the noise could be caused by dirty PCIe power voltages or electric fields that are always there inside any PC. This would also be a kind of noise that the HD400 can't remove. To remove noise of this kind, you'll need an audio filter. But the HD400 isn't a filter, it's a ground loop breaker.

I use the HD400 in the following setup:
PC -> [USB-C cable] -> interface (Presonus Quantum) -> [TRS cable] -> equalizer (dbx, for room correction) -> [TRS cable] -> HD400 -> [TRS/RCA cable] -> monitor amplifier (Denon) -> passive monitors.

Without the HD400, there was noise caused by a ground loop between PC/interface and the amplifier. With the HD400, there is silence.

I didn't test the GND Defender, but I do not believe that this expensive gadget can remove ground loops. The vendor states that every device connected to the GND Defender stays safely grounded. But you can't remove ground loops without breaking ground connections between devices. So having everything "safely grounded" means that there still are ground connections. The HD400 actually breaks ground connections, but it does this in the audio signal path (which is safe) rather than in the mains power path (which would be very dangerous!).

I consider the DC blocker as an expensive, but useless gadget as well. In my opinion, GND Defender and DC blocker are made to con money out of esoteric-minded HiFi enthusiasts.

Regards,

Michael

 

[Sebastian Holtzer]

Yes, you're right the HD400 does exactly the job but sadly there was still all the noise but very quiet and still audible but well noticeble reduced. Seems the PCIe is the real problem as you said. The iFi is expensive but did the job. I got a clean and silence signal. When it dangerous why is this beeing sold here in germany? I noticed all the safety Signs and I am sure there was the Number from the TÜV next to the CE Sign. Will try to use the Behringer on the Sub later this day. Maybe it will destroy the hum. Do you know if the hum is normal on the Sub 8Bt?

 

[brmichael]

The GND Defender probably isn't dangerous. It would be, however, if it would break ground connection in the mains power path. But as the vendor states "everything stays safely grounded", I assume that the GND defender doesn't break ground connection. If yes, it's safe but useless (at least it's useless for removing ground loops), because to remove ground loop noise, you must break ground connection. The people at TÜV test device safety (which the GND defender obviously passed), but they don't test if a device is useful

Unfortunately, I don't own a Sub 8Bt. But I think that subwoofers are most likely to output hum, because it's their job to transmit low frequencies. Does the Sub 8Bt receive it's input signal via Bluetooth? If yes, then there is no ground loop, because there is no "ground lead" in wireless connections. In this case, the hum has it's cause somewhere else in the audio chain. But I think it's a good idea to insert a HD400 in any wired connection between an audio source (output of an audio interface) and a power amplifier (amplifier of a powered speaker).

PCIe power noise isn't a problem, if the power voltages delivered by the PC are filtered on the interface card. I own a USB interface from ESI, its quality is fine. So I think that their PCIe cards are of good quality as well, at least regarding power supply. But getting rid of the high-frequency electric fields inside a PC is more difficult than filtering PCIe power. It requires good shielding, which means you have to encapsulate sensitive audio circuitry in a metal case. But there is no metal case on the Maya 44ex, so you have to rely on the PC being relatively "clean" inside. Of course I can see the advantages of a PCIe interface, such as low latency.

 

[SwitchBack]

Yes, you're right the HD400 does exactly the job but sadly there was still all the noise but very quiet and still audible but well noticeble reduced. Seems the PCIe is the real problem as you said. The iFi is expensive but did the job. I got a clean and silence signal. When it dangerous why is this beeing sold here in germany? I noticed all the safety Signs and I am sure there was the Number from the TÜV next to the CE Sign. Will try to use the Behringer on the Sub later this day. Maybe it will destroy the hum. Do you know if the hum is normal on the Sub 8Bt?

There is a difference between the earthing systems used in the US and in most of Europe. This difference also affects RFI filtering built into the power inlets on most gear. Gear built for the US and gear built for Europe use different arrangements, and I'm convinced that these differences make US gear used in Europe more susceptible to ground noise than gear specifically configured for use in Europe.

One way I found helps to minimise or even prevent problems is to make sure that the neutral pin on US gear is always connected to neutral on the power outlet, never to live, to avoid damage to the RFI filter. Depending on where you live (and whether power outlets in your country are keyed) that can be a challenge. Or apparently you can use a special arrangement RFI/hum filter as what must be those pricey iFi adapters, to remove the noise without lifting the ground (as that can be dangerous). Maybe those adapters even take care of the keying, automatically swapping live and neutral when appropriate. That would explain the price tag.

 

[brmichael]

@SwitchBack The Wikipedia article you provided a link for (thank you for that) doesn't mention any significant difference between US and Europe earthing systems. In both regions, earthing or grounding means to connect conductive housings of electrical appliances with a grounded potential. Main reason for this is safety: if the housing gets in contact with live voltage due to a part inside carrying live voltage getting loose or due to insulation failure, this will cause a short circuit, which will instantly interrupt power by blowing the fuse.

Theoretically, ground or earth potential should be the same on any outlet in the house. Practically, it isn't, depending on the structure of the internal wiring and the power that is taken from each outlet. The result are slight differences in ground potential between appliances. If there is an additional connection between these appliances such as an audio connection, these slight differences will result in AC flowing through the shield of the audio cable. That's what is called a "ground loop" and especially if the audio connection is unbalanced, it will cause hum noise on the audio signal.

To avoid ground loops, you have to break them at some place. But you should never ever do that on the mains power path, because if you cut the ground wire there, appliance housings lose their grounding and in case of a fault they will carry live voltage at their outer surface, which is life-threatening.

Fortunately, it is not necessary to break ground loops on the mains power path. Instead, one can do this on the audio signal path. In the Behringer HD400 a transformer is used for this purpose. Transformers pass signals from their inputs to their outputs through a magnetic field. Thus they provide a kind of an "air gap" between the ground of the audio source (e. g. an interface's output) and the ground of the audio sink (e. g. the input of powered speakers or a power amplifier). This "air gap" breaks the ground loop without affecting the audio signal and - very important - without causing any safety hazard.

You're right when suggesting to make sure that the neutral pin of an appliance is connected to neutral of the outlet. If turning the plug by 180 degrees is possible, one can swap neutral and live pins in order to reduce hum noise. But doing so does not eliminate ground loops, because ground loops run through the ground pin, which is not swapped. So even if the swapping is done automatically, you won't get rid of ground loop noise. But at least the GND Defender makes swapping possible on plugs that are keyed in a way you can't turn them. In many european countries, however, there is no need for such a device, as plugs are keyed in a way that allows turning them by 180 degrees.

 

[SwitchBack]

@SwitchBack The Wikipedia article you provided a link for (thank you for that) doesn't mention any significant difference between US and Europe earthing systems. In both regions, earthing or grounding means to connect conductive housings of electrical appliances with a grounded potential. Main reason for this is safety: if the housing gets in contact with live voltage due to a part inside carrying live voltage getting loose or due to insulation failure, this will cause a short circuit, which will instantly interrupt power by blowing the fuse.

Theoretically, ground or earth potential should be the same on any outlet in the house. Practically, it isn't, depending on the structure of the internal wiring and the power that is taken from each outlet. The result are slight differences in ground potential between appliances. If there is an additional connection between these appliances such as an audio connection, these slight differences will result in AC flowing through the shield of the audio cable. That's what is called a "ground loop" and especially if the audio connection is unbalanced, it will cause hum noise on the audio signal.

To avoid ground loops, you have to break them at some place. But you should never ever do that on the mains power path, because if you cut the ground wire there, appliance housings lose their grounding and in case of a fault they will carry live voltage at their outer surface, which is life-threatening.

Fortunately, it is not necessary to break ground loops on the mains power path. Instead, one can do this on the audio signal path. In the Behringer HD400 a transformer is used for this purpose. Transformers pass signals from their inputs to their outputs through a magnetic field. Thus they provide a kind of an "air gap" between the ground of the audio source (e. g. an interface's output) and the ground of the audio sink (e. g. the input of powered speakers or a power amplifier). This "air gap" breaks the ground loop without affecting the audio signal and - very important - without causing any safety hazard.

You're right when suggesting to make sure that the neutral pin of an appliance is connected to neutral of the outlet. If turning the plug by 180 degrees is possible, one can swap neutral and live pins in order to reduce hum noise. But doing so does not eliminate ground loops, because ground loops run through the ground pin, which is not swapped. So even if the swapping is done automatically, you won't get rid of ground loop noise. But at least the GND Defender makes swapping possible on plugs that are keyed in a way you can't turn them. In many european countries, however, there is no need for such a device, as plugs are keyed in a way that allows turning them by 180 degrees.

The devil is in the detail. I'm pretty well versed in all you wrote. In my vocabulary outlets that allow plugs to be inserted in more than one way are not keyed. Which means that on the appliance side you can't be sure which wire is live and which wire is neutral, so RFI filters (and PSUs) must be designed to work equally well either way. It also means that you can't declare one side in the circuitry 'neutral' and therefor similar to ground, something you can do and make use of when wall sockets are keyed.

Countries that do use keyed wall sockets (for several reasons including the way ground lines and neutral lines are allowed to be used) do have that certainty. Designers use it to their advantage, which makes those circuits no longer indifferent to LN orientation. Connect them the wrong way and they will work less good, may even sustain damage, and inject more noise than needed on ground lines shared with other gear. Hence my advice to make sure (US) gear is plugged in the right way, always.

As for ground potential in houses the question is: "In relation to what?". When 'Earth' is the reference then power consumption should have no influence on ground potential because power only uses LN, provided that all gear is good. Faulty gear may briefly dump current into the ground terminal until the fuse blows (live shorted to ground) or the GFCI trips (live or neutral shorted to ground), which should be exceptions. When neutral is the reference then power consumption will have a clear influence. And this is where the difference between earthing systems comes in. Somewhere in the power system ground and neutral are joined. Local regulations prescribe where that is, and therefore how close that is to the outlet. Which also influences how well the ground terminal works in keeping everything noise-free.

 

[brmichael]

Thanks for that explanation.

Are there rules in the US how to wire LN pins on power outlets? If yes, there is only one possible pin assignment, which an appliance designer can rely on. He can design the appliance in a way that works best with the pin assignment specified by the outlet. Pin swapping is not necessary and as a result, gadgets such as the GND Defender become obsolete (provided it works the way you described, which sounds plausible to me).

If there is no rule regarding wiring of LN pins on outlets (like in Germany and other EU countries), the position of the N pin is not always the same. In this case, the appliance designer should design the appliance in a way that it works good with any pin assignment. If he does so, pin swapping again is not necessary and the GND Defender is still obsolete.

On un-keyed outlets you can swap manually by simply turning the plug. That makes the GND Defender obsolete as well.

Besides that, there is one special situation in Europe, which also can happen in the US, I guess:
There are ungrounded appliances that have a 2-pin plug without a ground pin (for instance some HiFi gear). But regardless of the missing ground pin, these appliances do have EMI/RFI protection. As there is no ground pin, RFI protection consists of one condenser wired between the L pin and the housing and another condenser of the same capacity wired between the N pin and the housing. In this configuration, these condensers act as an AC voltage divider applying half of the mains voltage to the housing. In a 110V grid, this means that you can measure 55V AC from the housing to ground. However, the capacities of these condensers (around 10 nF) don't allow for currents that are dangerous to humans. You only can feel a little prickle when touching the housing of such an appliance. But regarding audio signals, 55 V is a lot and it definitely will cause hum noise when connecting a RFI-protected, non-grounded appliance with a grounded one. It also will feed AC to the ground pin of the grounded device, which is one of the reasons why ground potential is not always the same on all outlets in the house.

 

[Sebastian Holtzer]

If there is no rule regarding wiring of LN pins on outlets (like in Germany and other EU countries), the position of the N pin is not always the same. In this case, the appliance designer should design the appliance in a way that it works good with any pin assignment. If he does so, pin swapping again is not necessary and the GND Defender is still obsolete.

Do you speak from "Ausphasen" here? If yes, I thought this is complete bullshit, at least nowadays. While searching for my problem, I found a commentary that said that the Oelbach can't read the information correct with some modern power devices. That was the point why i did'nt tried that out before buying the iFi. Is there really a difference? Does it really can kill hum?