EMU0204 mods for FFT measurements

[Telstar]

Well I would gladly see an ADC replacement in the qa400.
Proprietary software if it's not bugged is not that bad...

Btw anyone knows or has used one of the Aaronia spectran devices?

[1audio]

I have tried 7-8 of the semipro cards and the RME and they all have problems. The ESI Juli@ seems to have the most benign interface and give the most consistent results. But its noise floor is not what it should be. I use it with the demo boards to get what I want. And you have a desktop computer on the back side. I can see making a replacement analog module for the ESI but a portable solution would be really great.

I posted some measurements showing what is possible with the AK5394A.

[davada]

Originally Posted by Telstar

Well I would gladly see an ADC replacement in the qa400.
Proprietary software if it's not bugged is not that bad...

Btw anyone knows or has used one of the Aaronia spectran devices?

Not so simple to do. They used a codec.

[Telstar]

Demian, do you want to try the yellowtec puc2?

[1audio]

I would not mind playing with one. just have no interest in spending more money on this stuff.

I looked into it. It seems to need drivers and run on an Atmel AVR32. The AudioWidget runs on an AVR32 and is fully UAC2 compliant. I'm pushing for a Digital input. Hopefully soon.

[soundchaser001]

Originally Posted by davada

I have arrived at R values to scale 0dB to the FS of the AK4385B.

The ADC FS is 2.9Vpp differential.

I give some details of performing the mod in another post.

Here are some schematics and results.

The first sch is the original. The second sch is the AKM recommended and the third sch is the mod.
The rest is self explanatory.

Cheers,

Hi David;

I notice that in the first schematic where you say it is the original; the op amps are all OPA-827s and the final is JRC2068s. I realized that there has been some gain scaling but did you also swap out the op amps?

Just curious.

Thanks
Matt

[davada]

Originally Posted by soundchaser001

Hi David;

I notice that in the first schematic where you say it is the original; the op amps are all OPA-827s and the final is JRC2068s. I realized that there has been some gain scaling but did you also swap out the op amps?

Just curious.

Thanks
Matt

Hi Matt,

No I didn't swap op amps. I just gabbed something from the symbol lib to use for the schematic. Next time I use the generic op amp to avoid confusion.

I see no need to change the op amps. The results are good as they are.

[staccatiss]

Tracker Pre on Windows XP SP3 runs at up to 192 kHz fine for me for years.


/S

Originally Posted by 1audio

Other notes (before I forget). The Tracker pre only runs at 44.1 and 48 on XP (at least with the drivers from EMU on their site). It runs up to 192 on Win 7. The 0404 does run up to 192 on XP. On Win 7 to get the input sensitivity down I need to set the gain in the windows mixer to 5 on the input. I still get occasional glitches at 192 with the EMU stuff.

I'll post a picture of the Tracker insides later this week.

[staccatiss]

Strange, people on thos board have measured the EMU1212m with much better results. See attachments.


/S

Originally Posted by davada

I've got the EMU1212 up and running but I've got to say I'm pretty disappointed.
I think this is a waist of a AK5394A. Just my opinion though. It took me over half an hour to get ARTA calibrated with this thing. It won't work with out the application that goes with it and that really get's in the way of third party apps.

See for yourself. This is no good for high resolution measurement and is another reason we are doing the Capture Widget project.

The first pic is self explanatory and the second is with a 75 ohm load on the input.

[staccatiss]

Here are a few of my own Tracker Pre measurements in loop back I did in 2011. Both with 48k and 192k. 48k gives lowest THD. 192k is only for testing.

Still not good enough.

/S