Loopback measurement of RME ADI-2 PRO FS (Black Edition)

[3125b]

The capture function in REW is great, very clean, very easy:

That's a Blackman Harris 7 window, most seem to use Hann. Doesn't seem to make much of a difference to me,.

 

[KSTR]

Forgive my ignorance, but isn't 32 bit pointless for pure playback? Even RME can't surpass 24 bit dynamic range...
I was led to believe that 32 bit is important for DSP, volume control and all that... Something that DAC does internally... And also a bigger number for advertising.

With a 32bit feed to the DAC, you have headroom for digital attenuation of the stream by the player/application then apply boost/EQ/etc in the RME and still have 24bit of resolution left. It can be done, cost nothing and just makes sense to implement it that way (internally, 24bit words are stored in 32bit anyway).

 

[Rja4000]

You can make stepped level tests in REW.

Sorry
I was aware of the stepped frequency but not of stepped level.
You're doing an awesome job

 

[3125b]

I've got another question:
If I want to measure a device under load, can I just put the load in parallel with the ADC, or does that mess something up?
Thanks in advance.

 

[polmuaddib]

Here's my RME ADI2pro fs be loopback measurement following Rja4000 suggestions. I might have skipped some, but i think i got most of them.

I set the generator on 1000 khz at -4.7dBfs and calibrated for 3.98 v which the multimeter showed.

 

[polmuaddib]

Right after RME, I connected JR Capri preamp in the loop and set the preamp to 85.5 value (In the JRC manual, it says that 85.5 is unity gain value at 0dB) which showed 4.09 v on the multimeter. It is a true RMS multimeter. So, I got 104.7 SINAD for Capri or 0.00058% SINAD, which I am happy with.
Now, if I made some mistake along the way, I only made worse measurements then possible, right?
Thanks

 

[3125b]

105dB SINAD is plenty good.
You can set REW to display voltage, you just have to set the correct input sensitivity (the RME has 4, 13, 19 and 24dBU wich equals 1.228, 3.46, 6,904 and 12,277Vrms respectively). Don't forget to turn off Auto Ref Level or it will throw you off (if you know wich general setting the device being tested falls). Also you can turn off the peak graph (settings -> trace options).

Here is a measurement of my early E30 with the suggested settings:

110.5dB SINAD is not too bad.

 

[polmuaddib]

105dB SINAD is plenty good.
You can set REW to display voltage, you just have to set the correct input sensitivity (the RME has 4, 13, 19 and 24dBU wich equals 1.228, 3.46, 6,904 and 12,277Vrms respectively). Don't forget to turn off Auto Ref Level or it will throw you off (if you know wich general setting the device being tested falls). Also you can turn off the peak graph (settings -> trace options).

Here is a measurement of my early E30 with the suggested settings:
View attachment 126885
110.5dB SINAD is not too bad.

Auto Ref is off, you can see it in the photo.
Thanks. And yes, 110dB is great.

 

[polmuaddib]

105dB SINAD is plenty good.
You can set REW to display voltage, you just have to set the correct input sensitivity (the RME has 4, 13, 19 and 24dBU wich equals 1.228, 3.46, 6,904 and 12,277Vrms respectively). Don't forget to turn off Auto Ref Level or it will throw you off (if you know wich general setting the device being tested falls). Also you can turn off the peak graph (settings -> trace options).

Here is a measurement of my early E30 with the suggested settings:
View attachment 126885
110.5dB SINAD is not too bad.

But I don't remember what the input sensitivity was... it might have been 24dBU. And, also, Auto Ref might have been on for the input.... I knew I messed something up. But, my results then could only be better, right? Not worse?