E1DA Cosmos ADC

[staticV3]

1. The output voltage of the mc cartridge is 0.3mV. ADC will amplify by 60dB and we get after the ADC - 300mV. At the ADC Cosmos the minimum sensitivity is 1.7V... Such a ratio of output voltage from the ACU to ADC sensitivity is normal? Wouldn't the recording be quiet and without dynamics?

The ADC has >120dB of dynamic range, while viny is said to have ~60dB of dynamic range. Even if your signal is too low to make full use of the ADCs DR, with vinyl, there's enough headroom that it does not matter:


Just make sure that after you're done recording, you normalize the recording to -0.5dBFS Peak or thereabouts.

2. If I use my phono preamp, with an output impedance of 850 ohms and +65dB for mс. Then for the same 0,3mV cartridge I will get 530mV and 850 ohms at the output. I.e. for normal impedance matching I have to choose in ADC Cosmos mode 43V and 13.6kOhm... But nothing will come out of this... How can I use the Cosmos ADC for recording?

I'd use the APU as pre combined with the ADC's RIAA mode.

 

[morillon]

Levels are one thing.
the input impedances another thing
,-)

 

[ManniX]

A future Cosmos ADC Pro with buffered inputs and gain control via UAC2 is planned.

Is the Cosmos ADC Pro still planned for the future?

 

[staticV3]

Is the Cosmos ADC Pro still planned for the future?

I don't think it is, at least not in the near future.

 

[restorer-john]

Just make sure that after you're done recording, you normalize the recording to -0.5dBFS Peak or thereabouts.

Why?

There's no good reason to force all recordings to close to 0dBFS.

 

[morillon]

Why?

There's no good reason to force all recordings to close to 0dBFS.

?
I imagine that this remark is due to the fact that you want to develop..
;-)

 

[somebodyelse]

Why?

There's no good reason to force all recordings to close to 0dBFS.

Having all tracks at least in the same ballpark avoids nasty surprises when changing tracks.

 

[IVX]

I made some unification for the original Cosmos ADC and Cosmos ADCiso FW to match digital frequency responses. Both ADC versions will share the same FW. However, due to hardware differences, the analog frequency responses are different, hence, we need two compensation files, one for Cosmos ADC and another for Cosmos ADCiso. Both files flatten the response down to +/-.1db from .8Hz to 383.98kHz(Minimum phase filter setting FFT widow is Flat-top), or let's say +/-.3db for unlucky tolerance.

 

[MC_RME]

Did I miss something? What is this about? 'Match digital frquency responses - which ones and why?

 

[IVX]

Look, the original Cosmos ADC had Fs_max = 384kHz, and it was optimized for the max DR with no care about the frequency response >192kHz.
Next, I gave the FW with 768k mode, and now I prepared Cosmos ADCiso with 768k mode officially. I found that the noise-optimized FW has too fast roll-off >200kHz. In the proposed today FW I turn Off that trick every time 768k of Fs is selected to obtain a higher roll-off. 44.1k, 48k ..384K are the same as the original Cosmos ADC i.e. optimized for a low-noise.

 

[pma]

It is a good idea. When we make measurements of FR in high resolution, we can clearly see in-band ripple coming either from DAC used or ADC used. It is a question of filters used and it is good to know.

 

[Joachim Herbert]

@IVX, @MC_RME I would call this RME-like ongoing development and quality of support. Highly appreciated!

 

[Joachim Herbert]

Just make sure that after you're done recording, you normalize the recording to -0.5dBFS Peak or thereabouts.

I'd rather look for -3 dBFS for the album to maintain relations between songs and avoid every chance of intersample clipping.

 

[Zung]

... now I prepared Cosmos ADCiso with 768k mode officially...

My use case: output transformers for tube amps. The better ones have resonances at about 100KHz, outside of the jurisdiction of common ADC/DAC's.

 

[Music1969]

Finally, we decided to order 500pcs Cosmos Scaler production, perhaps, at the same time when we'll order Cosmos ADCiso i.e. during a few weeks.
Cosmos Scaler THD performance test. The input-to-output H3 difference is 1.4db at -161db i.e. Cosmos Scaler(gain=0db) residual H3 is below -175db@1kHz 1.7Vrms and 640ohm of Cosmos ADC input. Hence, at +26db H3 is expected at -150db. At the higher Cosmos ADC range(>1.7V) H3 should be even lower.
For more detail, Archimago test is here: https://archimago.blogspot.com/search?q=Scaler
View attachment 293411
View attachment 293412

Nice - will you sell cables to connect Scaler to Cosmos ADC ?

 

[Thomas_A]

I am just pretesting the unit E1DA having D10s as source. The first loopback was with the macbook only on battery and I got a lot of noise (need some USB isolator probably). With Mac mini->D10s->E1DA->macbook (battery) I get some 50/100 Hz noise. Not sure where it comes from. Poor cables/interference?

 

[pma]

The result is nasty as expected. You need USB isolator to put into D10s USB link. Olimex works for me

USB-ISO

Full speed USB isolator 1000VDC for protecting your PC or laptop while connecting USB devices wired to high voltages CE certified

www.olimex.com

Olimex will not work with Cosmos.

 

[Thomas_A]

The result is nasty as expected. You need USB isolator to put into D10s USB link. Olimex works for me

USB-ISO

Full speed USB isolator 1000VDC for protecting your PC or laptop while connecting USB devices wired to high voltages CE certified

www.olimex.com

Olimex will not work with Cosmos.

Thanks, so this is GND/USB noise between mac mini and the D10s and not looped through the Cosmos USB? Using the macbook (battery) only gave even worse noise, so the USB/GNDs are really noisy. Much worse than my cheap old Transit DAC/ADC.

(I will make an order another day - going for heart surgery on Thursday. Ordered these units to have some fun during my convalescence. )

 

[Paulvaso80]

Thanks, so this is GND/USB noise between mac mini and the D10s and not looped through the Cosmos USB? Using the macbook (battery) only gave even worse noise, so the USB/GNDs are really noisy. Much worse than my cheap old Transit DAC/ADC.

(I will make an order another day - going for heart surgery on Thursday. Ordered these units to have some fun during my convalescence. )

Thomas, I wish you the best of luck with your surgery!!

 

[Thomas_A]

Thomas, I wish you the best of luck with your surgery!!

Thanks!