Qudelix 5k as input for 8010?

[MKreroo]

I currently have the 5K as my face/amp, and am about to grab a pair of 8010.

Given the XLR input of the Genelec, I was wondering if it's feasible to grab a 2.5mm to XLR cable to hook up the Genelec with the 5K.

 

[solderdude]

Yes, feasable.
You may have to make such a cable yourself most likely. I have no idea if they exist.

 

[staticV3]

2.5mm to 2x XLR adapters exist, but they can be dangerous due to a lack of GND connection between the two devices.
however, it should be fine as long as the 5K is not connected to mains (keep it on battery)

 

[solderdude]

OP could always use the 3.5mm output and go SE in on the 8010 but that might increase the chance of ground loops.
No chance of that with the 2.5mm as there isn't even ground (only hot and cold) but the signals are ground referenced in the Qudelix.

OP could also opt for the IK multimedia Iloud MTM instead of the 8010, same price class.

 

[MKreroo]

OP could always use the 3.5mm output and go SE in on the 8010 but that might increase the chance of ground loops.
No chance of that with the 2.5mm as there isn't even ground (only hot and cold) but the signals are ground referenced in the Qudelix.

OP could also opt for the IK multimedia Iloud MTM instead of the 8010, same price class.

I've actually been trying to decide whether if I want 8010 or IKM micro.

The MTM is a bit too large for my need as I need a rather portable setup.

Seems like though 8010 is not the best option to have the 5K use as input, think I'll move to IKM instead.

 

[MKreroo]

2.5mm to 2x XLR adapters exist, but they can be dangerous due to a lack of GND connection between the two devices.
however, it should be fine as long as the 5K is not connected to mains (keep it on battery)

Do you mind explaining a bit more about the lack of ground in this setup and how it's dangerous?
If the 5K is connected to another device (PC etc) through USB would it be fine?

 

[solderdude]

8010 over micro anyday.
MTM over 8010. Especially in a portable setup where one never knows about the local acoustics and one is always close to the monitors. In this case nothing beats the MTM (have to use the ARC mic). You will always have a true reference with you. The 8010 will not be that. The sound will change depending on room acoustics.
The ARC works surprisingly well.
You just cannot play very loud (with both of them). The MTM will be able to play louder when you set to 80Hz roll-off in which case it is similar to the 8010.
At normal levels the MTM can reach 40Hz. No sub needed for monitoring.


The possible danger is because of a so called floating ground. There can potentially be a larger voltage difference between the inputs of the speaker amps and safetyground.
In such a case the input circuits (assuming no transformers are used in the speaker input circuit which I would assume aren't there) could be damaged by a too high exterior voltage between safety ground and the inputs.

Now, in this case the outputs of the Qudelix (both - and +) are referenced to the internal 'common' of the Qudelix so there won't be an issue. That is until the Qudelix is connected to a device (in portable setups connected to unknown gear or voltages) there could be a potential issue.
This isn't there when balanced signals are used that have a common/ground as that will serve as a ground reference.

When you use it as a system from a common mains voltage (so speakers and music source connected to the Qudelix all plugged in the same powerstrip) there is no potential issue anyway.
when speakers and source are not plugged in the same power source and something is very wrong with mains then there could be an issue.

I would expect the inputs of the Genelecs to have some kind of 'protection' on board but don't know for sure.

 

[maverickronin]

The 8010's are class II with no safety ground.

 

[solderdude]

iLoud MTM are class-I and signal ground is connected to safety ground.

 

[rnd]

The 8010's are class II with no safety ground.

iLoud MTM are class-I and signal ground is connected to safety ground.

As I understand it, floating the ground with 2.5mm balanced to 2xXLR cable, as the OP wants to do, would be safe on the 8010 but not so safe on the iLoud MTM, when the Qudelix is charging.

By the way they sell a cable that also does have the ground connection separately which goes into the 3.5mm connector right next to the 2.5mm on the Qudelix 5k. If properly wired, that would make it safe for both. Not that I think the two connectors would actually fit next to one another on the Qudelix 5k.. you may need to file the jacks flatter I'm afraid I haven't tried, but I'm somewhat tempted. I'm using unbalanced with class I monitors, with some minor but nevertheless annoying noise from a ground loop.

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www.aliexpress.com

 

[solderdude]

As I understand it, floating the ground with 2.5mm balanced to 2xXLR cable, as the OP wants to do, would be safe on the 8010 but not so safe on the iLoud MTM, when the Qudelix is charging.

Interesting cable...

It actually is the other way around.
When the Qudelix is charged using a faulty (leaking) charger there can be a voltage present on the enclosure of the speaker (tingling when touching it). With the iLoud that current would be going directly to safety ground and thus is safe to touch.

The class 2 speakers are less likely to be troubled by a ground loop.

 

[rnd]

It is the other way around.
When the Qudelix is charged by a faulty (leaking) charger there can be a voltage present.

The class 2 speakers are less likely to be troubled by a ground loop.

Ah, of course happy to be corrected. Should have read more carefully. Thank you!

That would mean, in my current setup, which is: laptop (class I grounded) -> Qudelix 5k over USB -> a set of class I monitors, I can safely let the ground float when using a balanced connection. All of this is plugged into the same outlet.

Still.. just to be sure I fully understand:

With [a class I monitor] that current would be going directly to safety ground.

Trying to visualize this, let's say we have the following scenario:
- audio source that has a leaky charger
- there is zero voltage between hot and return on the output of the source
- there is unexpected 50V between the hot (and return) on the source and the ground of the monitor
- the XLR cable between the source and the monitor is unplugged

So now I plug the XLR cable into the monitor. On the input we now have:
- ground: monitor's own ground at 0V
- hot: 50V relative to ground
- return: 50V relative to ground

You mentioned this scenario is OK saying that "that current would be going directly to safety ground" but it sure looks dangerous to my amateur eyes.

Since you did say it's safe, I suppose these "uneven ground" situations are producing only small currents? So in practice, it would not end up being 50V once I plug it in, but some much smaller voltage trending towards 0V, with currents small enough to not cause trouble for the input circuitry?

 

[solderdude]

Trying to visualize this, let's say we have the following scenario:
- audio source that has a leaky charger
- there is zero voltage between hot and return on the output of the source
- there is unexpected 50V between the hot (and return) on the source and the ground of the monitor
- the XLR cable between the source and the monitor is unplugged

So now I plug the XLR cable into the monitor. On the input we now have:
- ground: monitor's own ground at 0V
- hot: 50V relative to ground
- return: 50V relative to ground

There is one vital ingredient for this to become problematic which is current.
Now, suppose there is 50V and this is current limited to 10A and is opposite ground.
You touch this you might feel a little tingle. Not so dangerous.
Now, when you connect a class 1 device current will flow and it will be high (10A current limit), sparks will fly but the voltage on the speakers will be just a few volt.
So will the +/- signal be 0V and the metal chassis of the speaker will also not have a high voltage, so safer to touch than without safety ground. It is why it is called safety ground.
If one were to connect a class-1 device that has the metal chassis connected to signal ground no current will flow but the 50V will be on the metal enclosure of the speaker.
Less safe to touch but no audible ground loop.

You mentioned this scenario is OK saying that "that current would be going directly to safety ground" but it sure looks dangerous to my amateur eyes.

Since you did say it's safe, I suppose these "uneven ground" situations are producing only small currents? So in practice, it would not end up being 50V once I plug it in, but some much smaller voltage trending towards 0V, with currents small enough to not cause trouble for the input circuitry?

Safe to touch is not the same as safe for equipment. In practice the leakage currents will always be there. Transformers, SMPS all have leakage currents but they do differ in amplitude and even spectrum. In general these are very low though. mA territory at worst. But even in 1ohm (ground wire of poor interlink) this could result in mV level hum.
The lower the leakage current (class-2) or balanced + ground the lower the ground loop hum will be.

The fun part of ground wires is that they are low resistance so any ground loop currents flow through that path. That path should be around the electronics (so via ground planes and or chassis and to safety ground if present.

Now, in the Qudelix circumstances (not using the Aliexpress cable) the 50V will flow through the output of the Qudelix (also low R out) through the input of the amp (in the speaker) to ground. That is through the input resistors. Depending on the used circuit (opamp) the inputs may have an extra resistor inside and/or clamping diodes preventing the input voltage to exceed that (+ 0.something volt).
Here's the thing. We do not know what punishment the inputs can handle but professional gear usually can take a beating. Again, not all of them.

In class 2 there is no damage to the gear because the leakage currents are low. In class 1 it depends on the design.
For safety of humans (not being able to touch voltages opposite ground) the class 1 is safer than class 2. For the gear itself ... it depends.
I prefer human safety over that of equipment.

 

[AnalogSteph]

That would mean, in my current setup, which is: laptop (class I grounded) -> Qudelix 5k over USB -> a set of class I monitors, I can safely let the ground float when using a balanced connection. All of this is plugged into the same outlet.

Indeed.

With Class II monitors, any old 3.5 mm to XLR adapter cable with a shield connection (plus 2.5 mm to 3.5 mm adapter) should get the job done.

In class 2 there is no damage to the gear because the leakage currents are low. In class 1 it depends on the design.
For safety of humans (not being able to touch voltages opposite ground) the lass 1 is safer than class 2. For the gear itself ... it depends.
I prefer human safety over that of equipment.

One could argue that it's not the Class II equipment's fault if a connected device has excessive mains leakage. (Typical culprits for this tend to be devices which expect their mains leakage to be drained by what they are connected to, e.g. a TV by antenna / cable / satellite installations or an old printer via its host computer.)

Besides, in the rare case of a badly miswired outlet with L connected to where PE should go, the Class II equipment would remain safe (if nonfunctional) while Class I may result in electrocution. Under normal circumstances though, Class I is easy and straightforward for equipment designers - follow a few basic rules and your equipment is as safe as they are generally going to get, hence its popularity in the DIY space. Getting Class II right is a greater challenge.

Incidentally, to my understanding a device that does use PE but just for mains filter currents and nothing else (with proper levels of insulation from the secondary) would still qualify as Class II.

 

[NiagaraPete]

I've actually been trying to decide whether if I want 8010 or IKM micro.

The MTM is a bit too large for my need as I need a rather portable setup.

Seems like though 8010 is not the best option to have the 5K use as input, think I'll move to IKM instead.

What about a G one? Pretty much the same but also has line level in.

 

[MKreroo]

Not sure why but some of the replies weren't showing in my notification but some did...

Thanks for the detailed explanation, don't think I quite digest the information yet but will spend some more time looking into it.

8010 over micro anyday.
MTM over 8010. Especially in a portable setup where one never knows about the local acoustics and one is always close to the monitors. In this case nothing beats the MTM (have to use the ARC mic).

MTM with ARC seems to be just amazing, it really tempted me but the size is something for me to consider, probably will be the next step up.
Given some of the reputation of the Micro (port resonance etc) I was wondering about the reliability of the MTM, it does seem fine but saw some reports of amp failing.

Went with a pair of Fostex PM03 for now as I happened to stumbled across a pair for cheap, will see how that size goes for desktop and portable.

 

[solderdude]

Longevity could be an issue. Hope to not find out and if it does so then within the warrantee period.

Port noise at low frequencies is very audible though. These are thus not without fault. Their biggest plus is the ARC. How much of a plus that is becomes evident when you move them around now and then. Really easy to do, no hassle with software. Just the mic + pressing a button and presto... reference sound (nearfield only).

 

[MKreroo]

Longevity could be an issue. Hope to not find out and if it does so then within the warrantee period.

Port noise at low frequencies is very audible though. These are thus not without fault. Their biggest plus is the ARC. How much of a plus that is becomes evident when you move them around now and then. Really easy to do, no hassle with software. Just the mic + pressing a button and presto... reference sound (nearfield only).

so I ended up ordering a pair of MTM, and given that it has 1/4 TRS, I suppose a 1/8" to 2 1/4" would work just fine? (no problem with floating ground etc like with the Genelec?)

 

[solderdude]

 

[MKreroo]

Ohhh, now I see, so since 2.5mm does not have the ground section like single-ended ones do, there's no common ground (as mentioned earlier). Thanks