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E1DA Cosmos ADC

Hemi-Demon said:
What is the difference between Bundle 1, 2, 3 and 4?
Click to expand...
Screenshot_20220511-091307.jpg Screenshot_20220511-091342.jpg
Grade 0 is >129dB(A)
 
Your APU working as a phono preamp is an interesting feature I could use.
It looks like it does 60dB gain which would make it usable with MC cartridges. But is it possible to change the resistance to get a proper load with a MC cartridge?
 
MC_RME said:
Un passe-haut pour se débarrasser du DC fait partie de N'IMPORTE QUEL ADC audio, donc le DC est généralement inférieur à -100 dBFS. Personne ne veut avoir DC dans son enregistrement. J'ai déjà expliqué à Ivan (je ne sais pas pourquoi il a écrit "Je ne sais pas pourquoi ils s'en soucient" ci-dessus):

Citation : le Cosmos ADC a un problème de base : la quantité élevée de courant continu (généralement -56 dBFS). Cela entraîne parfois des données de mesure erronées (par exemple, dans HpW, la valeur RMS inclut toujours DC), et pour l'enregistrement audio, cela provoque des pops/clics au démarrage/arrêt et à l'édition d'un enregistrement. /Devis

C'est juste une mauvaise pratique et contre la norme, cela ne causera que des problèmes inattendus tôt ou tard.

Maintenant, le problème avec les ADC ESS est que leur passe-haut inclus, qu'ils ont osé renommer DC Block dans leurs dernières fiches techniques, est un filtre 25 Hz implémenté de manière bâclée, voir ce graphique :

View attachment 163106

Et améliorer DC uniquement à -85 dBFS. Il est inutilisable pour les mesures et l'enregistrement audio. N'IMPORTEZ QUEL autre ADC vous offrez un filtre raide de 1 Hz et un DC crunch jusqu'à -130 dBFS !

J'ai donc proposé à Ivan d'essayer l'option de compensation DC intégrée, une caractéristique unique de l'ESS, qui pourrait compenser le DC de manière similaire à la compensation THD, et pourrait être ajoutée facilement à l'application Tweak . Ivan a réussi à atteindre -120 dBFS de cette façon, mais comme nous parlons de microvolts, ce décalage est un peu différent par appareil et a entraîné -90 dBFS sur mon appareil. Cela s'est terminé par l'idée d'ajouter un décalage DC de base à toutes les unités, pour aller mieux que le -56 dBFS par défaut, et d'ajouter en plus les paramètres de décalage DC à l'application Tweak.

Maintenant, c'est à Ivan ce qu'il fait.
Click to expand...
 
silly question..
the value of mkp capacitors etc. has been calculated, certainly high, which could be put upstream to cut the dc without damaging the measurements too much.. or for certain uses justifying it more than keeping maximum characteristics...
?
;-)
 
Another problem, maybe someone can help me. Balanced output from Topping DX5 headphone amplifier (4pin XLR). I am doing THD+N measurements. The first plot of Cosmos ADC shows very high noise multiples of 50 Hz. The second is Motu M4. It turns out that Cosmos has lower harmonics, but interference multiples of 50 Hz is simply terrible. Measurements from the unit's line output are excellent, but these are very strange. What could be the problem? How to remove distortion multiples of 50 Hz.

thd.1652966716.png


thd.1652966717.png
 
And the second question, I did not find a description of the changes in ADC firmware number 13. What exactly has changed and should I update from version 12?
 
The launch firmware for the Cosmos ADC was v10.
It had inverted polarity and a DC offset of about -60dBFS (iirc).

Ivan later released firmware v13 with the following improvements:

-DC offset reduced to about -95dBFS
-Polarity fixed
-MCLK routed to ES9822 pin 36 for external i2s to Spdif/AES bridges
-Cosmos ADC now announces itself to USB hosts as self-powered. This can help with using it on iPads or iPhones

The only disadvantage of updating the firmware is that the factory calibration for 2nd harmonic distortion may be lost, requiring recalibration.
 
SyncerTech said:
Another problem, maybe someone can help me. Balanced output from Topping DX5 headphone amplifier (4pin XLR). I am doing THD+N measurements. The first plot of Cosmos ADC shows very high noise multiples of 50 Hz. The second is Motu M4. It turns out that Cosmos has lower harmonics, but interference multiples of 50 Hz is simply terrible. Measurements from the unit's line output are excellent, but these are very strange. What could be the problem? How to remove distortion multiples of 50 Hz.

thd.1652966716.png


thd.1652966717.png
Click to expand...
I see there is a GND loop issue or/and GND even not connected. In case of GND loop you can try USB ISO like Topping HS01, our discord guys reported it works with Cosmos ADC. Also, you can use a battery-powered laptop as a ADC USB host. In my PC(desktop AC-powered) no GND loop at all if I using USB port directly from the mother-board, one for the DAC another(closest one) for Cosmos ADC.
 
IVX said:
I see there is a GND loop issue or/and GND even not connected. In case of GND loop you can try USB ISO like Topping HS01, our discord guys reported it works with Cosmos ADC. Also, you can use a battery-powered laptop as a ADC USB host. In my PC(desktop AC-powered) no GND loop at all if I using USB port directly from the mother-board, one for the DAC another(closest one) for Cosmos ADC.
Click to expand...
Yes, I forgot to say. I'm using a battery powered laptop for testing. I tried through the insulator from Topping, I also thought there would be an improvement, but the result did not change. The DX5 DAC itself is mains powered (tried different outlets). I test from two USB ports on my laptop and from a phone + Cosmos is connected to the laptop. Now I do a lot of measurements with Cosmos, usually everything is fine from the balance. In this case, there is an incomprehensible problem.
 
SyncerTech said:
Yes, I forgot to say. I'm using a battery powered laptop for testing. I tried through the insulator from Topping, I also thought there would be an improvement, but the result did not change. The DX5 DAC itself is mains powered (tried different outlets). I test from two USB ports on my laptop and from a phone + Cosmos is connected to the laptop. Now I do a lot of measurements with Cosmos, usually everything is fine from the balance. In this case, there is an incomprehensible problem.
Click to expand...
The headphone's output always has low output impedance, hence, the AC line noise should be even lower than line-output.
Pls try to draw a simplified diagram of your connections, maybe I can offer some optimization.
 
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