RME LNI-2 DC honest talk

[antcollinet]

I don't use the ADI-2/4 PRO SE under maximum load, so my goal is to improve its performance under light to medium load.

Thing is, the RME devices already perform better than human hearing can detect.

Even if there were a measurable improvement, it can make no audible difference.

 

[MaxwellsEq]

I think I explained why in #3.

Thanks. Although @johny_2000 seems to be happy that he won't need the higher current...

 

[johny_2000]

Reading your quote in post #2 RME seem to be suggesting that the cascaded double regulators inside the 2/4 PRO are so good that a better external PSU is not worthwhile (implying that there is a benefit to be had for previous devices such as the DAC and 2 PRO).

This is exactly what I am trying to prove or disprove. The presence of the LNI-2 device must imply some need for it for end users.
Let's see how true this is from an engineering point of view.

 

[johny_2000]

Thing is, the RME devices already perform better than human hearing can detect.

Even if there were a measurable improvement, it can make no audible difference.

Thank you. I completely agree with this. But my goals are not an audible difference, but a measurable one.

 

[johny_2000]

Friends, does this look like a good candidate as a competitor for LNI-2?

 

[antcollinet]

Exactly. My current ADC (not RME) is capable of measuring 126 dB SINAD @ 1kHz. Quite close to the best AP analyzers.

And the RME is specced at THD of -130dB, and SNR of >120dB

Even if there were a difference, and your test setup were perfect, I doubt your ADC will be able to measure it.

 

[MaxwellsEq]

The presence of the LNI-2 device must imply some need for it for end users.

For owners of the ADI 2 PRO FS R Be or the ADI 2 DAC, perhaps?

 

[johny_2000]

Even if there were a difference, and your test setup were perfect, I doubt your ADC will be able to measure it.

At the moment, on all the spectral analysis graphs of this device I see a hum of about -130 dB from the mains (60 Hz) and its harmonics (120 Hz, 240 Hz, 300 Hz).

 

[johny_2000]

For owners of the ADI 2 PRO FS R Be or the ADI 2 DAC, perhaps?

Sorry, I don't know the target category of users of this device. I'm trying to find its usefulness for myself with ADI-2/4 PRO SE.

 

[Grotti]

For owners of the ADI 2 PRO FS R Be or the ADI 2 DAC, perhaps?

I own the first one. No need for any upgrade: stellar performance with the stock PSU.

 

[MaxwellsEq]

Sorry, I don't know the target category of users of this device. I'm trying to find its usefulness for myself with ADI-2/4 PRO SE.

The way I read it is that RME believe that the PRO 2/4 is the state of the art and doesn't need an upgraded PSU, but that the older PRO 2 and DAC don't have the cascaded 2/4 regulators and so this device brings the PRO 2 and DAC in line with the 2/4. So if you have the older devices, you may benefit from this device, but if you have the 2/4 you won't benefit.

 

[voodooless]

The presence of the LNI-2 device must imply some need for it for end users.

Yes, RME says so:

This results in an enhanced audio signal and sound quality avoiding humming, buzzing and other noises that can be caused by power supplies or dirty mains power

So if you have no humming, buzzing or other noises, it does nothing.

 

[voodooless]

At the moment, on all the spectral analysis graphs of this device I see a hum of about -130 dB from the mains (60 Hz) and its harmonics (120 Hz, 240 Hz, 300 Hz).

Nope:

 

[KSTR]

The presence of the LNI-2 device must imply some need for it for end users.

The "need" is mainly to appeal to the audiophile community where RME has aquired a lot of customers, especially with the ADI-2 DAC. In these circles those ugly cheap wall-warts have a bad reputation.

For a few selected expert measurements and in a few consumer scenarios a low mains-leakage supply has benefits, as noted in previous posts. This were the new linear supply is significantly better than the stock supplies which are Class-II, two-prong and have tons of nasty leakage current as the rectified input AC is directly connected to the secondary side with a capacitor (1nF, typically), to pass EMC tests.

But again, as noted, a cost-efficient way to reduce leakage is a good DC/DC converter (I'm using TRACO THM-15), and of course galvanic isolation of the digital connection. And clamp-on ferrites on all(!) cables.

 

[johny_2000]

Nope:View attachment 396040

Glad you don't have one. Could you share some details about your setup?

I'll be posting my graphs with all possible power supply combinations soon.

 

[voodooless]

Glad you don't have one. Could you share some details about your setup?

It's not my graph, I already linked it in this post:

RME LNI-2 DC honest talk

Let's start this conversation with officially published information. "Meanwhile, the LNI-2 DC serves as a DC filter engineered to effectively isolate the DC signal, ensuring flawless power delivery to any RME Audio device*. * Note: not recommended for use with the ADI-2/4 Pro SE." Okay, why is...

www.audiosciencereview.com

The fact that this one is clean, and (some) others are not, already shows that the PSU is most likely not the source of potential hum.

 

[johny_2000]

But again, as noted, a cost-efficient way to reduce leakage is a good DC/DC converter (I'm using TRACO THM-15), and of course galvanic isolation of the digital connection.

TRACO THM 15-1212
Ripple and Noise: 75 mVp-p typ
Leakage current: less than 2.5 µA

Considering that galvanic isolation is more important than actual output characteristics, are you satisfied with this module? Have you measured its efficiency?

 

[johny_2000]

The fact that this one is clean, and (some) others are not, already shows that the PSU is most likely not the source of potential hum.

We'll see it soon!

 

[antcollinet]

At the moment, on all the spectral analysis graphs of this device I see a hum of about -130 dB from the mains (60 Hz) and its harmonics (120 Hz, 240 Hz, 300 Hz).

Even if this were coming from the PSU (And the chart shown above by @voodooless suggests it is not) we are still, with -130dB - in Angels-dancing-on-the-head-of-a-pin territory.

 

[Sokel]

I'll quote @MC_RME posts about it so there's no confusion:

The leakage current of the ADI's external power supply runs to ground, whereever it finds one. With nothing connected you (your body) is the ground. The phones are in the way and therefore emit audible hum. Touching the chassis short-circuits the path of the leakage current, so it won't flow over the headphones anymore. Solution is the same as always: either connect a grounded device to the ADI, or directly connect it to ground.

Because of cases like yours we changed the power supplies to grounded ones. But as we have a lot of stock currently only the 2/4 Pro comes with it. And even that one will fail in case your power outlets don't have PE/ground (like many in Japan, Thailand...).

The last resort (if someone is unwilling or unable to connect it to a solid ground) is the use of a linear power supply. Their leakage current is basically free of harmonics and therefore typically inaudible.

(link)

Ground issues, a ground loop, or no ground aka leakage current issues, or leakage with wrong grounding - all this could be cured by a linear power supply. But this is noise that shouldn't be there and is clearly audible as such. It's not some mysterious bass, mid, treble, soundstage, veiled issue. A different ps will not change the basic sound of an ADI-2 unit at all.

(link)