RME LNI-2 DC honest talk

[johny_2000]

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 that?
That's exactly what I wanted to use it for!

 

[johny_2000]

Power Supply
In order to make operating the ADI-2/4 Pro SE as flexible as possible, the unit has a universal DC input socket, accepting voltages from 9.5 Volts up to 15 Volts. An internal switching regulator of the latest technology with high efficiency (> 90%) prevents internal hum noise by operating above audible frequencies. Internally the switching regulator is followed by standard linear regulators, followed by super low-noise linear regulators. Therefore the ADI-2/4 Pro SE achieves its technical specs even with less optimal power supplies. Or in other words: the choice of power supply is not critical. Still the unit includes a high-quality switching power supply, 12 V / 3,3 A, which not only accepts any mains voltage between 100 V and 240 V (usable worldwide), but is also fully regulated against voltage fluctuations and suppresses line noise.

 

[voodooless]

use with the ADI-2/4 Pro SE

Do you have hums, buzzing or other noises? If not, why would you want to buy such a thing?

The reason for not recommending it is probably the 30W max power consumption of the Pro SE vs the 24W the PSU gives.

 

[johny_2000]

My goal is measurement. This applies to both DAC and ADC.
And I'm going to compare the LNI-2 power supply for the ADI-2/4 Pro SE with a 12V lithium battery in terms of noise level.

 

[voodooless]

My goal is measurement.

Measurement of what? From what can be seen the thing already measures as good as it gets:

RME ADI-2/4 Pro SE - Auto-measured with Multitone

I don't know if this post is about the extremely nice, new RME ADI 2/4 Pro SE interface or about the new automated measurement capability of the Multitone app :) Most of these measurements were done automatically using a Multitone test plan (I'll share in a separate post). This new feature...

www.audiosciencereview.com

 

[MaxwellsEq]

If you search for RME linear power supply, there are several vendors making money selling pointless upgrades to an already extremely well measuring and performing device. Perhaps RME thought "if customers feel they need such a thing, it would be better if we designed it, so that it properly compliments the internal regulators in our kit".

 

[Purité Audio]

RME thought, we should be profiting rather than somebody else.
Keith

 

[johny_2000]

This site appears to be based on evidence-based engineering. Since I couldn't find any real measurements of the ADI-2/4 PRO SE inputs (ADC) and outputs (DAC) with and without the LNI-2 DC power supply, I'm going to make my own measurements and compare them to a clean 12V DC source, such as a lithium battery.

 

[KSTR]

For measurements, it's way more important to isolate the USB connection. Low leakage supply is the icing on the cake, and the simplest way is to add a medical DC/DC converter between the stock supply and the RME -- that's what I do with my ADI-2 Pro's.

 

[KSTR]

Since I couldn't find any real measurements of the ADI-2/4 PRO SE inputs (ADC) and outputs (DAC) with and without the LNI-2 DC power supply

There will be no difference when looking right at the connectors. Everything that could ever happen is happening in the connection cables (R*I drop from mains balancing current flowing on the shield).

 

[johny_2000]

For measurements, it's way more important to isolate the USB connection. Low leakage supply is the icing on the cake, and the simplest way is to add a medical DC/DC converter between the stock supply and the RME -- that's what I do with my ADI-2 Pro's.

Thank you. My USB connection to this device is already isolated using Intona High-Speed USB Isolator 7054.

 

[MaxwellsEq]

Since I couldn't find any real measurements of the ADI-2/4 PRO SE inputs (ADC) and outputs (DAC) with and without the LNI-2 DC power supply, I'm going to make my own measurements and compare them to a clean 12V DC source, such as a lithium battery

It's a relatively recent product, hence no-one has bought one and measured it yet. So, well done!

But, your first post said it's not recommended for the 2/4 PRO.

 

[johny_2000]

For measurements, it's way more important to isolate the USB connection. Low leakage supply is the icing on the cake, and the simplest way is to add a medical DC/DC converter between the stock supply and the RME -- that's what I do with my ADI-2 Pro's.

Great! Could you please share some details about the actual parts used?

 

[johny_2000]

But, your first post said it's not recommended for the 2/4 PRO.

Well, it wasn't me who said that, it was RME itself. Will we prove it or not?

 

[MaxwellsEq]

Well, it wasn't me who said that, it was RME itself. Will we prove it or not?

I'm confused. I must confess I've not read RME's material about it, but are they claiming: a) there's no benefit with the 2/4 PRO, or b) it will damage the 2/4 PRO?

 

[antcollinet]

This site appears to be based on evidence-based engineering. Since I couldn't find any real measurements of the ADI-2/4 PRO SE inputs (ADC) and outputs (DAC) with and without the LNI-2 DC power supply, I'm going to make my own measurements and compare them to a clean 12V DC source, such as a lithium battery.

What are you going to measure it with?

Your measurement gear needs to be more sensitive and more accurate than the devices you are measuring - which are already pretty much the best of the best, unless you are going to be measuring with something similar performance to the AP gear that Amir uses.

 

[johny_2000]

I'm confused. I must confess I've not read RME's material about it, but are they claiming: a) there's no benefit with the 2/4 PRO, or b) it will damage the 2/4 PRO?

I guess it doesn't have enough output current to power 2/4 PRO at maximum load.
The LNI-2 DC is rated at 2 Amp.

The ADI-2/4 PRO specs:
- Standby power consumption DC 12 V: 170 mW (0.014 Amp)
- Idle power consumption: 14 Watts (1.16 Amp)
- Max. power consumption: 30 Watts (2.5 Amp).

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.

 

[johny_2000]

Your measurement gear needs to be more sensitive and more accurate than the devices you are measuring - which are already pretty much the best of the best, unless you are going to be measuring with something similar performance to the AP gear that Amir uses.

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

 

[voodooless]

I'm confused. I must confess I've not read RME's material about it, but are they claiming: a) there's no benefit with the 2/4 PRO, or b) it will damage the 2/4 PRO?

I think I explained why in #3.

 

[MaxwellsEq]

I guess it doesn't have enough output current to power 2/4 PRO at maximum load.
The LNI-2 DC is rated at 2 Amp.

The ADI-2/4 PRO specs:
- Standby power consumption DC 12 V: 170 mW (0.014 Amp)
- Idle power consumption: 14 Watts (1.16 Amp)
- Max. power consumption: 30 Watts (2.5 Amp).

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.

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).