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Old 14th March 2013, 04:37 AM   #91
1audio is offline 1audio  United States
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A quick update on my observations. First the EMU Tracker Pre and the )$)$ use the same ADC, AK5385a as does the ESI Juli@ and the RME HDSP9632. The analog implementations vary and the RME seems to have the best (most robust) interface to the host PC. It should given its market and application, but even that will get hammered if I start something line a VNC session moving screens remotely.

Attached is the RME loopback distortion and noise floor. This is going through the Praxis so the internal opamps in the Praxis are limiting the performance some. Its lower 2nd Harmonic that I get with the other devices on loopback. I'll connect the ShibaSoku later this week to get an idea of what can be expected.

I get much better results from the AKD5394A demo board.

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.
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File Type: jpg RME loopback distortion -10 dBU levels.JPG (109.8 KB, 346 views)
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Old 14th March 2013, 04:59 AM   #92
davada is offline davada  Canada
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Quote:
Originally Posted by 1audio View Post
A quick update on my observations. First the EMU Tracker Pre and the )$)$ use the same ADC, AK5385a as does the ESI Juli@ and the RME HDSP9632. The analog implementations vary and the RME seems to have the best (most robust) interface to the host PC. It should given its market and application, but even that will get hammered if I start something line a VNC session moving screens remotely.

Attached is the RME loopback distortion and noise floor. This is going through the Praxis so the internal opamps in the Praxis are limiting the performance some. Its lower 2nd Harmonic that I get with the other devices on loopback. I'll connect the ShibaSoku later this week to get an idea of what can be expected.

I get much better results from the AKD5394A demo board.

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.
That's typically windows. Start up another application and anything heavy on resources slows everything down.

What is this 'the )$)$ use".

"I need to set the gain in the windows mixer to 5 on the input."

Is there any way to bypass this altogether? This really gets in the way.
When I use the EMU0204 I leave everything in windows cranked up all the way just to be sure. If this got changed and not noticed our measurements would be useless.
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Old 14th March 2013, 05:27 AM   #93
1audio is offline 1audio  United States
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Originally Posted by davada View Post
What is this 'the )$)$ use".
Sorry, Typo, its EMU 0404.

I found the gain issue on Win 7 calibrating the Tracker to Praxis. Its a specific process and really removes a lot of errors. I was getting a really limited dynamic range and then I discovered in loopback I had to reduce the gain setting regardless of the analog settings.

Ultimately these music interfaces need a lot of tweaking/modification to work for measurement.

The RME is better suited. In its +4 mode its 3V out and in, which would work much better for audio. However its too expensive and has a lot of stuff that's not necessary for the task. The same for the Juli@ card. However they are desktop cards and less flexible in use.
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Old 14th March 2013, 06:17 PM   #94
1audio is offline 1audio  United States
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With the devices on hand (my Juli is apart right now) this EMU 0404 is the best result. The RME did not do as well. Not sure why yet. This is 16 dB below FS. The analog in needs to be set for clipping at 3V to get this result. I think a lot has to do with the limited supply voltages in the EMU boxes. The RME has other things going on with analog gain switching etc. I'm not sure where performance gets lost in it. The absolute scale is not correct so ignore it.
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File Type: jpg EMU0404 .5V in THD.JPG (111.5 KB, 304 views)
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Old 14th March 2013, 07:17 PM   #95
Telstar is offline Telstar  Italy
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I think the esternal psu helps the emu.
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Old 14th March 2013, 07:37 PM   #96
iko is offline iko  Canada
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Originally Posted by Telstar View Post
I think the esternal psu helps the emu.
I don't think so, unfortunately. The usb 0404 gets 5V externally. But then, it uses a number of DC-DC converters to provide various other voltages (including negative potential). I found those to be sources of noise.

E-MU 0404 USB mod wiki - diyAudio
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Old 15th March 2013, 12:51 AM   #97
davada is offline davada  Canada
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Analog Device data sheets and application note stress not to use switching supplies with there ADC evaluation kits. The kits come equipped with an analog power supply.

I think there is a clear message here.

Cheers,
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Old 16th March 2013, 02:51 AM   #98
RNMarsh is offline RNMarsh  United States
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tell me again... why are we reinventing this ADC tester thing? Instead of enlisting QA400 modifications from QuantAsylum guys (or others)? Are they willing to help get us what we want, the way we want it? -RNM
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Old 16th March 2013, 03:09 AM   #99
davada is offline davada  Canada
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tell me again... why are we reinventing this ADC tester thing? Instead of enlisting QA400 modifications from QuantAsylum guys (or others)? Are they willing to help get us what we want, the way we want it? -RNM
First of all Rick we are not the target market for the QA400. It's targeted to the Chinese manufactures. Not much money in DIY electronic hobbyist. I don't think they will do much more with the QA400 but there maybe something else in the works down the road.
We'll have to wait and see. The QA400 is closed. It's proprietary technology. Have you had much luck using it with any other software?

Secondly and more importantly this is our project by us and for us. I will get a lot more satisfaction from doing this than from any product I might buy. It's interesting, gratifying and educational.
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Old 16th March 2013, 03:22 AM   #100
davada is offline davada  Canada
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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.
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File Type: gif 1212.GIF (90.1 KB, 261 views)
File Type: gif 1212loaded.GIF (86.0 KB, 253 views)
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