Topping D10s + E1DA Cosmos ADC as a measuring system

[IVX]

This thread has been very useful for me in developing a Cosmos-based measurement setup. However I have not had any success with the Olimex USB-ISO.

My setup is a MacBook Air (2020) running REW, Topping D10s, and the Cosmos ADC. As in several posts above, the loop Mac --> D10s --> ADC --> Mac is very noisy. Inserting the Olimex USB-ISO did not work at all (Mac --> USB-ISO --> D10s --> ADC --> Mac). The D10s is recognised and seems to work but the results were awful. I looked at the output of the D10s on a scope and could see that the signal was appearing and disappearing intermittently, and stopped completely after a few seconds. Nothing I could do would fix this, including supplying power to the USB-ISO.

So I gave up on that, and tried the Topping isolator instead (HS01). This seems to work as it should and I get pretty clean results. I still need to experiment but the D10s is showing THD+N of -108dB right now, so things are at least ok.

I don't know if my USB-ISO is faulty or if it just does not play nicely with the Mac and D10s combo but I thought I'd relate this experience in case it is helpful for others.

you may search in our discord channel, I remember a few USB ISOs mentioned as successfully used with Cosmos ADC.

 

[deadwood83]

This thread has been very useful for me in developing a Cosmos-based measurement setup. However I have not had any success with the Olimex USB-ISO.

My setup is a MacBook Air (2020) running REW, Topping D10s, and the Cosmos ADC. As in several posts above, the loop Mac --> D10s --> ADC --> Mac is very noisy. Inserting the Olimex USB-ISO did not work at all (Mac --> USB-ISO --> D10s --> ADC --> Mac). The D10s is recognised and seems to work but the results were awful. I looked at the output of the D10s on a scope and could see that the signal was appearing and disappearing intermittently, and stopped completely after a few seconds. Nothing I could do would fix this, including supplying power to the USB-ISO.

So I gave up on that, and tried the Topping isolator instead (HS01). This seems to work as it should and I get pretty clean results. I still need to experiment but the D10s is showing THD+N of -108dB right now, so things are at least ok.

I don't know if my USB-ISO is faulty or if it just does not play nicely with the Mac and D10s combo but I thought I'd relate this experience in case it is helpful for others.

TI has an EVM for USB isolation rated to 480mbps. Shows as $49 USD for me. TI's EVMs are typically made to impeccable quality standards. https://www.ti.com/tool/ISOUSB211DPEVM#tech-docs

 

[IVX]

TI has an EVM for USB isolation rated to 480mbps. Shows as $49 USD for me. TI's EVMs are typically made to impeccable quality standards. https://www.ti.com/tool/ISOUSB211DPEVM#tech-docs

the last time I tried to get that chip(1K pcs) in China was in August - no way.. Only samples.

 

[holla]

Olimex USB-ISO is (like vast majority of older inexpensive isolators) full speed only (i.e. 12Mbps). Very likely one/both of the devices are not happy with that.

Right, thanks -- I thought it could be something like that. @pma reports above that the Olimex device works fine with the D10S DAC, so I guess the issue is on the Mac end, which is not particularly surprising -- it only has USB-C ports which have to be converted to B to connect to the USB-ISO. I did try a number of ways of doing that including a separate powered hub but nothing worked.

The Topping isolator does work though, at least so far.

 

[phofman]

The Topping isolator does work though, at least so far.

Topping HS01 is specced as high-speed (480Mbps)

 

[holla]

Topping HS01 is specced as high-speed (480Mbps)

Yes, I didn't intend my comment as a contradiction to you at all - in fact it is the opposite, providing some evidence that the speed is the issue.

 

[phofman]

Sure, I did not mean it like that either

 

[Jeromeof]

I am very interested in getting a Cosmos ADC and starting to do some of my own measurements, but I am not particular good at building electronics - any links to a good voltage / input divider on aliexpress or similar?

 

[Holmz]

I am very interested in getting a Cosmos ADC and starting to do some of my own measurements, but I am not particular good at building electronics - any links to a good voltage / input divider on aliexpress or similar?

You just need 2 resistors per channel.

what is your divide by ratio?

 

[IVX]

I am very interested in getting a Cosmos ADC and starting to do some of my own measurements, but I am not particular good at building electronics - any links to a good voltage / input divider on aliexpress or similar?

don't forget that Cosmos ADC has AUX input 35-43Vrms(depends on the sensitivity switch 1.7-10Vrms), so, probably you don't need any kinda dividers at all.

Cosmos ADC | index

e1dashz.wixsite.com

 

[Jeromeof]

Sorry to resurrect this thread but I am ready to buy some cheap DAC measurements kit and potentially Amp / headphone Amp gear for a bit of summer fun:

I am looking for hopefully reasonable accurate DAC measurements and / or measurements of some Class D Amps (including headphone Amp) as I have a few of these "toys" that I would like to experiment with a little.

Roughly I would spent maybe €400 / €500 on whatever would be required and I have a friend who is an electrical engineer can probably assist if I need something 'custom' (like the divider mentioned above - though unclear to me if I need that) and the dummy load mentioned below.

So from reading the forums it looks like I would need say (for both DAC and Amps):
1. High quality ADC - e.g. Cosmos APU
https://www.audiophonics.fr/en/devi...anced-adc-es9822pro-32bit-384khz-p-15762.html
2. USB isolotor:
https://www.olimex.com/Products/USB-Modules/USB-ISO/
3. High quality DAC (for Amp testing) e.g. Topping D10s
https://www.audiophonics.fr/en/dac-...sd-256-xmos-u208-es9038q2m-black-p-14686.html
4. Some dummy loads (for amp testing) e.g. thinking of building something like this:
http://diyaudioprojects.com/Testeq/Dummy-Speaker-Load/
5. Some suitable cables
6. REW + lots of time

Anyway, any advice would be great.

 

[SIY]

I would *strongly* suggest using a single ADC/DAC and spending the money saved on something like Jan Didden's Autoranger to use as a front end. That will not only protect the ADC/DAC, but it will extend your measurement range and make life much, much easier.

 

[Jeromeof]

I would *strongly* suggest using a single ADC/DAC and spending the money saved on something like Jan Didden's Autoranger to use as a front end. That will not only protect the ADC/DAC, but it will extend your measurement range and make life much, much easier.

Any specific recommendations for a single ADC/DAC in my price range.

All I can really see in Europe is probably this:

RME ADI-2 FS Balanced ADC DAC :​

RME ADI-2 FS Balanced ADC DAC Headphone Amplfier SPDIF ADAT AES/EBU SteadyClock FS 24Bit 192kHz - Audiophonics

The RME ADI-2 FS is a compact and extremely flexible 2-channel ADC/DAC converter. Despite its small size, the unit allows high quality conversion to and from SPDIF, AES and ADAT up to 192kHz.

www.audiophonics.fr

But that would be well over my budget.

 

[SIY]

Any specific recommendations for a single ADC/DAC in my price range.

All I can really see in Europe is probably this:

RME ADI-2 FS Balanced ADC DAC :​

RME ADI-2 FS Balanced ADC DAC Headphone Amplfier SPDIF ADAT AES/EBU SteadyClock FS 24Bit 192kHz - Audiophonics

The RME ADI-2 FS is a compact and extremely flexible 2-channel ADC/DAC converter. Despite its small size, the unit allows high quality conversion to and from SPDIF, AES and ADAT up to 192kHz.

www.audiophonics.fr

But that would be well over my budget.

The sorts of interfaces sold for music production (e.g., Focusrite, M-Audio...) work very well and are reasonably priced.

 

[Jeromeof]

The sorts of interfaces sold for music production (e.g., Focusrite, M-Audio...) work very well and are reasonably priced.

OK Interesting!

I have a Behringer Audio Interface already:

Behringer U-Phoria UM2

USB Audio Interface 16 Bit / 48 kHz, 2 Inputs and 2 outputs, 1 x combo plug XLR/6.3 mm jack and 1 x 6.3 mm jack, Xenyx microphone preamp including 48V phantom power, Guitar input, Signal and clip display, Direct monitoring, 6.3 mm jack headphone...

www.thomann.de

But I would never have thought it good enough for any measurements. If there some post I can get more detail on what would work best?

Thanks

 

[Sokel]

something like Jan Didden's Autoranger to use as a front end. That will not only protect the ADC/DAC, but it will extend your measurement range and make life much, much easier.

Bear with my newbieness,but my question is if the mentioned autoranger is in any way tied to ground as it would be useless for me.
I am interested but I have to be sure.

 

[Sokel]

OK Interesting!

I have a Behringer Audio Interface already:

Behringer U-Phoria UM2

USB Audio Interface 16 Bit / 48 kHz, 2 Inputs and 2 outputs, 1 x combo plug XLR/6.3 mm jack and 1 x 6.3 mm jack, Xenyx microphone preamp including 48V phantom power, Guitar input, Signal and clip display, Direct monitoring, 6.3 mm jack headphone...

www.thomann.de

But I would never have thought it good enough for any measurements. If there some post I can get more detail on what would work best?

Thanks

It's a 16-bit device,I think it won't be very useful.

 

[SIY]

Bear with my newbieness,but my question is if the mentioned autoranger is in any way tied to ground as it would be useless for me.
I am interested but I have to be sure.

Fresh From the Bench: The Linear Audio Autoranger Mk II Measurement Interface

Stuart Yaniger explores new possibilities in audio measurement systems, expanding on the basics of using sound cards combined with new accessible-to-all software tools, such as REW, and a recently improved measurement interface option. That option is the Linear Audio Autoranger Mk II Interface...

audioxpress.com

Has both balanced and single ended inputs.

 

[SIY]

OK Interesting!

I have a Behringer Audio Interface already:

Behringer U-Phoria UM2

USB Audio Interface 16 Bit / 48 kHz, 2 Inputs and 2 outputs, 1 x combo plug XLR/6.3 mm jack and 1 x 6.3 mm jack, Xenyx microphone preamp including 48V phantom power, Guitar input, Signal and clip display, Direct monitoring, 6.3 mm jack headphone...

www.thomann.de

But I would never have thought it good enough for any measurements. If there some post I can get more detail on what would work best?

Thanks

How low in distortion are you trying to measure? For 0.00x, a Focusrite Scarlett will work beautifully. If you want to get to 0.000x, you may have to stretch your budget.

 

[Jeromeof]

How low in distortion are you trying to measure? For 0.00x, a Focusrite Scarlett will work beautifully. If you want to get to 0.000x, you may have to stretch your budget.

OK thanks - I will investigate a bit more this evening.

So you are saying that the Focusrite Scarlett solo (or its bigger brothers?) + the Autoranger + REW etc would be good enough for some initial DAC measurements?