E1DA Cosmos ADC

[HarmonicTHD]

Yes, HiFiGo is our reseller, the same as Linsoul, and Audiophonics.

Thanks. Although eyeing the Cosmos ADC for some time, I never had the time to look closer, so I started started digging into it a bit today and noticed Audiophonics has them in stock for EU. I used to use my audiointerface but that only goes to about 95dbSINAD and fiddling with the gain and input voltages is a pain and has a big chance of letting the magic smoke escape.

1) Next to your website, are there some good posts/descriptions on how to use it best e.g. for amp measurements (sort of step by step manual)? (it would shorten the research a bit - thx.). (I use REW, but also just discovered Multitone Analyser, inspired by @pma post today).

2) For measuring BTL power amps (mine has ca. +-36V rail voltage, am I correct, to connect the speaker out positve to the XLR pin2 in and the speaker out negative to the XLR pin3 in (just doublechecking, so the smoke stays in)?

Sure I wouldnt be able to go full power, but that is ok (my load is the limiting factor here anyhow).
(Quote from your website: "... Cosmos ADC has 2 FDA XLR inputs 1.7-10Vrms, and a tiny 2.5mm 43Vrms AUX input as a gift to DIYers who like to play with power amps(do not plug/unplug that jack when the amp is On!). All inputs are AC coupled(-7.5V to +2.5v DC allowed) Fully Differential aka balanced and could be used with balanced/unbalanced outputs in any combinations i.e. doesn't matter +IN to GND or -IN to GND or IN+ to the OUT+ or to OUT-, the same for IN- etc....")

Thanks.

 

[IVX]

+/-36V bridged is too much indeed. Better to use additional in serial resistors inserted into the XLR inputs. If you like you can read our discord discussion, where we have almost everyday questions about how to measure something by ADC or APU.

 

[HarmonicTHD]

+/-36V bridged is too much indeed. Better to use additional in serial resistors inserted into the XLR inputs. If you like you can read our discord discussion, where we have almost everyday questions about how to measure something by ADC or APU.

Thanks. Will have a look at Discord. Also I am in the process of reading through Archimago´s Musings, as he offers a bit of a step-by-step description on how to conduct measurements. Any better sources, next to the Discord and Archimago?

 

[enricoclaudio]

Thanks. Will have a look at Discord. Also I am in the process of reading through Archimago´s Musings, as he offers a bit of a step-by-step description on how to conduct measurements. Any better sources, next to the Discord and Archimago?

I’m on the same boat Step-by-step descriptions are what I need too…

 

[HarmonicTHD]

I’m on the same boat Step-by-step descriptions are what I need too…

Archimago got me a good step forward. If I understood correctly, unless you want to measure DACs very accurately, you are good with the Cosmos ADC and dont need the Cosmos APU. However, be aware that the Cosmos is limited to 43Vrms max in, so be careful when hooking up an power amp (see also @IVX comment above) and check if you have a bridged or non-bridged power amp.

EARLY LOOK: E1DA Cosmos ADC - affordable high performance measurements for the audio hobbyist!

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

 

[enricoclaudio]

I got the APU only because it was cheaper to get it at the same time with the ADC. Also the APU allows to measure at low levels and increases SINAD performance of the ADC. But yes, for most DACs, the ADC alone is more than I would ever need.

 

[IVX]

Archimago got me a good step forward. If I understood correctly, unless you want to measure DACs very accurately, you are good with the Cosmos ADC and dont need the Cosmos APU. However, be aware that the Cosmos is limited to 43Vrms max in, so be careful when hooking up an power amp (see also @IVX comment above) and check if you have a bridged or non-bridged power amp.

EARLY LOOK: E1DA Cosmos ADC - affordable high performance measurements for the audio hobbyist!

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

on the other hand, you don't need Cosmos ADC if you already have some just Ok ADC if you'll add to the bench Cosmos APU. For example, any laptop's onboard audio input + APU(DR test up to 60db improvement) overtakes Cosmos ADC for the AES17 Dynamic Range test, and some laptops + APU(gives THD+N 30db of improvement) may outperform Cosmos ADC for the THD+N@1k test.

 

[HarmonicTHD]

on the other hand, you don't need Cosmos ADC if you already have some just Ok ADC if you'll add to the bench Cosmos APU. For example, any laptop's onboard audio input + APU(DR test up to 60db improvement) overtakes Cosmos ADC for the AES17 Dynamic Range test, and some laptops + APU(gives THD+N 30db of improvement) may outperform Cosmos ADC for the THD+N@1k test.

Ah I see. Thanks for the hint, my current ADC (Audio interface Focusrite 4i4 - which I use for recording/mixing etc) "only" gets to about 95db SINAD in a loop test and 110dB DR (manufacturer specs) but the amps, which I am having in mind to measure are more towards 114dB SINAD and 122db DR.

So with the APU's 60dB improvement (noise), I would get to way over let´s say 140dB DR (theoretically ca. 110db+60db DR)? Is that thinking correct?

 

[enricoclaudio]

I'm making the APU - ADC cables and wanted to confirm that these are right:

DAC to APU: XLR Female to TRRS

APU to ADC: TRRS to XLR Male

Following this at the TRRS end connector:

Numbers are the pins at the XLR 3 Pins Male and Female connectors.

 

[staticV3]

@enricoclaudio you can use this as reference: https://cdn.discordapp.com/attachments/715055107271688232/1038812076300312636/APU_to_ADC.png

 

[enricoclaudio]

@enricoclaudio you can use this as reference: https://cdn.discordapp.com/attachments/715055107271688232/1038812076300312636/APU_to_ADC.png

Thanks but I already have TRRS connectors and Mogami quad balanced cable in hand so I'm going to use those to not purchase any more connectors. Makes sense?

 

[staticV3]

Thanks but I already have TRRS connectors and Mogami quad balanced cable in hand so I'm going to use those to not purchase any more connectors. Makes sense?

Sure. You can still use the graph as reference for what wire should go where. Even if you're using different connectors.

 

[pjug]

Can the range settings for L and R be set independently to record two signals that have very different levels? It looks like 6 switches for each channel so the how-to would be straightforward.

 

[staticV3]

@pjug the laser engraving next to the DIP switches explains how to set the input sensitivity:

And yes, each channel can be set independently.

 

[Grooved]

@pjug the laser engraving next to the DIP switches explains how to set the input sensitivity:
View attachment 263577
And yes, each channel can be set independently.

Thanks @staticV3
I used it a lot, but totally forgot from the first use that it's possible to set each channel independently

 

[MrOtto]

Then Cosmos is unable to be used with most DACs in unbalanced operation? Anyone here cares to actually test some DACs in on RCA outputs, please?

See Archimago testing a Topping D10S using XLR to RCA adapters: https://archimago.blogspot.com/2021/09/early-look-e1da-cosmos-adc-affordable.html

So this would be the ideal device to rip vinyls?

 

[pma]

Then Cosmos is unable to be used with most DACs in unbalanced operation? Anyone here cares to actually test some DACs in on RCA outputs, please?

Absolutely no problem, just make a 3- wire RCA to XLR cable. Low distortion remains same.

 

[eeMGee]

@pjug the laser engraving next to the DIP switches explains how to set the input sensitivity:
View attachment 263577
And yes, each channel can be set independently.

After 7 months of occasional use the DIP switches in my Cosmos ADC in left channel start to loose contact - I am looking for spare one. This should be good as replacement:

https://www.mouser.sk/ProductDetail/Wurth-Elektronik/416131160812?qs=2kOmHSv6VfSn2jguIjHTtg==

Martin

P.S.: 1000 Cycles are not real - my guess is 100 is the most...

 

[IVX]

eeMGee, I believe, you can get back switch functionality if drop on it some IPA 98-99% and multiple switch On/Off/On/Off.

 

[eeMGee]

Thanx, I will try. But it is too early if contacts need cleanning...

And it is hard to detect this problem - to check/recalibrate after each DIP change is not very easy.