DIY Audio Analyzer with AK5397/AK5394A and AK4490

[soongsc]

I am pretty sure that the electromagnetic radiation is the main culprit. Otherwise PaulBC would not have been able to achieve the results he did by moving the transformar 1.2 m away, see DIY Audio Analyzer with AK5397/AK5394A and AK4490



I assume that what you describe is some sort of common mode noise or incorrect ground connections in the power supply. This can also be an issue, but I don't think it is the main problem in this case.

I really have not had the time to explore and confirm in this particular device. But if two outputs are used in a transformer, just the slight phase difference between the windings can cause issues resulting in a very small glitch which flows through the ground. I can hardly believe with all the shielding we already have in this product, we would still have electromagnetic issues. But I may be wrong. Just my two cents...
I am not sure how pulling the transformer out of the chassis was conducted, but increased wiring and connection could also have some effect on phase as well at this low level of amplitude.

 

[1audio]

I'm not sure how different windings on a transformer can have small phase differences. Maybe if they are under severe load but normally the phase relationship is pretty much locked by the common magnetic field.

 

[Kay Pirinha]

By loading one (of two) secondary windings ohmicly and the other one reactively, maybe? Or one capacitively and the other one inductively? But I'm not sure how this might cause glitches or spikes.
Best regards!

 

[anatech]

Hi dreamth,

But dot't lie yourself, none of those who bought this project at a discount are poor, they are smart people and smart people are actually good with financials.

That is not true in my case. I had to save up, which I started to do when I first became aware of the project, then I had to borrow from a friend. I made this happen for me, and it wasn't easy or one of my proudest moments asking for a loan. I am disabled, and the insurance that was covering me ejected me from the program, so I have a tiny social insurance income that doesn't even cover basic needs.

I would be surprised if I was the only person in this situation. However, this instrument is helping me make more money just through what I can learn from it, and the savings in time it brings. Once I learn how to program Virtins MI, it will be even better for me. So I really made a bet on the future to make this happen back in time. It was a very good bet.

-Chris

 

[Kay Pirinha]

Where from is this MI software available?


Best regards!

 

[BSST]

@anatech

I agree with at least part of dreamth's comment: I think you've demonstrated you are in fact smart and good with financials! Kudos! 🙂

 

[ergo]

Where from is this MI software available?

Best regards!

Multi-Instrument, a powerful multi-function virtual instrument software - Virtins Technology

 

[anatech]

Hi BSST,
My wife would disagree. 🙂
But thanks.

Thanks ergo, it is the very good folks at Virtins that created this software and added the RTX as a native device. I was going to buy Virtins MI even before they added the RTX, and that was after a lot of looking at all the packages I could find. ARTA will function, and I bought that as well first. Before I was made aware of Virtins MI program.

They also have a thread around here somewhere. Here is the GB thread: GB for Virtins MI Pro for RTX6001 autoranging/autoscaling & for soundcard end users

-Chris

 

[31697B]

Are all the bugs and upgrades worked out and now it is perfect? WIN10 i7 SSM


THx-RNMarsh

 

[JensH]

As you know, nothing is perfect. But I don't think there are major flaws left.
As I see it, there were two bugs, one concerning distortion at relatively high levels and one regarding a potential instability with inductive sources. Those have been solved.

One improvement has been implemented as well.
Shields over the input stages have been added to reduce the crosstalk from the generator outputs to the inputs.

I am still working on an alternative power supply, replacing the toroidal transformer with a switch mode supply board + an external adapter. I hope to get PCB's back from manufacturing (bare boards) next week. These are for those users who don't like the mains hum at around -150 dBV. The test version of the supply got the mains hum down below the noise floor, which is around -168 dBV (with a 512k FFT).

What do you mean by "WIN10 i7 SSM"?
There have been some issues with Win10 and the Thesycon USB driver, with some builds of the Win10 creating problems, probably due to conflicts between the Win10 UAC2 drivers and the Thesycon driver.
I mainly use Win7 and I have limited experience with Win10. On this forum I have not heard of problems with Win10 lately.

 

[NicMac]

One improvement has been implemented as well.
Shields over the input stages have been added to reduce the crosstalk from the generator outputs to the inputs.

To this I would add the implementation of the S/PDIF output.
Works flawlessly and is very useful when testing DACs.

 

[JensH]

Right, I forgot about that one. I also use this for DAC testing.
But that is more like an added feature, not bug fixing or an improvement.

 

[mlloyd1]

Hi Chris:

I use ARTA and Virtins MI.

Nice stuff; wish I had these "toys" YEARS ago!
🙂

mlloyd1

Hi mlloyd1,
....
What software package are you using with it? MI controls the unit and will run a sequence of steps, automating tasks.

-Best, Chris

 

[anatech]

Hi mlloyd1,
I know exactly how you feel!

-Chris

 

[lemon]

Jens, thank you for this marvelous equipment machine!

I couldn't imagine the limit of this machine, here is a Zo (PSU) with the floor of measurement on 0.1mOhm (!). The software that I used, is the MI Pro.

 

[mbrennwa]

...here is a Zo (PSU) with the floor of measurement on 0.1mOhm

Is this the residual impedance of the PSU output, or is this the residual of the cables, connectors and stuff used in the measurement setup?

 

[lemon]

Probably, this is the residual Zo of PSU+cables+connectors.

I don't know for the rest, I used the "Power Supply impedance Measurement" from the list of Virtins MI-Pro DUT Measurements.
I used short input-outputs cables (20cm, well made) with bnc and xlr connectors.

I had a very low Zo measurement with a 0.7mOhm on the LT3042 before, but now this measurement of TPS7A4901DGNT was extremely very good!

 

[1audio]

I think there may be a scaling error. 1 cm of thick wire is 1 milliOhm. If you have a 1 Ohm or less resistor check the readings with that.

 

[jan.didden]

Is this a 4-wire measurement?
Agree with Demian, wiring is more than this.

Jan

 

[JensH]

It would indeed be interesting to see a schematic of the measurement setup, with exact indication of how it is connected. With a 4-wire setup it might be doable, but extreme care is needed at these impedance levels.