Cosmos APU a notch+LNA $70 to outperform APx555b for $30000

[IVX]

I did update the first post with APU's Notch freq. responses.

 

[lykkedk]

your notch isn't active and requires quite a big and different corrections for H2(-10db) and H3(-5db). APU's Notch is active, H2 and H3 have about .5db difference, that's why I can simply subtract 30db from the THD+N reading.

Okay... cool i got it now. -Finally!

I was wondering why the use of active notch, (also the fact that opamp's nomatter what do add some minor distortion) I see now why!
I will continue making some experiements with the passive i have now. -But i should really collect an active one sometime

Thank's for the indeept explanation @IVX

Jesper.

 

[matulo_g]

Why APU has got SE outputs if it is Cosmos ADC addition (with balanced inputs)?

Thanx.

M

 

[IVX]

Why APU has got SE outputs if it is Cosmos ADC addition (with balanced inputs)?

Thanx.

M

A cost-effective solution, of course. Cosmos ADC inputs are FDA i.e. balanced/unbalanced both are fine.

 

[Ultima Thule]

Hi Ivan,

if I understood it correct the ADC chip used in your product can handle 768 kHz sampling frequency, is it possible to run or upgrade Cosmos ADC to handle this frequency?

Cheers, Michael

 

[IVX]

Hi Ivan,

if I understood it correct the ADC chip used in your product can handle 768 kHz sampling frequency, is it possible to run or upgrade Cosmos ADC to handle this frequency?

Cheers, Michael

no, the limit is CT7601CR USB audio bridge.

 

[Ultima Thule]

Ok I see, I checked the brief data sheet for CT7601xx family and there is a pin compatible version in same QFN48 package called CT7601PR with 768 kHz, if we replace with this chip, what else would you have to do to enable the functionality for the higher sampling rate?

 

[IVX]

the current FW works up to 384k, you'll need to change FW code.

 

[IVX]

BTW, if anyone needs the ASIO for Cosmos AADC in Windows, was found some strange but tested way to install 2 Comtrue drivers one by one and finally got the native ASIO works.
So the voodoo is as follows:
a) Install the latest Comtrue driver from here https://www.comtrue-inc.com/index.php/download2/summary/4-ct7601/12-windows-7-10-driver
b) Let Windows restart and install another one from there https://drive.google.com/file/d/11LDzaULXWbtP1fyH6j7sp2S2SOF5ve3x/view?usp=sharing
Probably needed to restart again but in my case, it doesn't.
REW works with Comtrue ASIO and no error was reported.

 

[capslock]

Ivan, your Aliexpress store seems to be having problems.

I cannot find it or any of its products by searching within the store. I can access it through a google search or from your homepage. However, when I click on a product, I keep getting "Sorry, no matches were found for your refined search." This happens in Chrome and Edge.

 

[IVX]

hm, strange, Sunny has no idea about that, she asked Aliexpress manager about that.

 

[capslock]

Am I the only one experiencing this? I just tried on a work computer that is run through a completely different provider, same result.

 

[IVX]

I can see that with USA VPN.

 

[IVX]

Actually, I almost have no Cosmos APU currently because I got already 12000pcs these fuc..ng switches, and wave-soldering is still not finished ))
The first attempt melted 4000pcs. Next 4000pcs supplier gave me as a "thermal resistant" plastic inside, but I tested that and found 100.0% the same as previous 4000pcs. Finally, the supplier gave me 4000pcs more and these were Ok. So, 12000pcs totally.

 

[IVX]

The practically achieved number is -132db, I've no sine source better yet. I just finished the Matlab simulation of the THD+N with an ideal 1kHz sine + real APU noise with exactly the same notch+20-20kBW as AP2700 SW does. As you can see, a noise-limited THD+N value is -134.8db@1kHz@10Vrms(APU Notch gain 0db) i.e. about 10db better than APx555b. I have to mention that my ADC sensitivity was 2.7V which corresponds to about 8.8Vrms APU input at 1kHz(+20db gain -30db notching = 10db or 3.16x times), hence, 10Vrms input has about 1db room. The correction should subtract .5 to 1db from the THD+N simulation above i.e. the limit is around -135.5db.

 

[capslock]

I can see that with USA VPN.
View attachment 1068517

Yes, I can see the same page but when I want to look at any of the products listed, I get what I have attached:

 

[1audio]

From the US "via Comcast" I have been able to navigate the Aliexpress stee and see the items. However there are several "stores" selling the E1DA stuff. DD-audio, Transformer and amplifier etc. Are they selling real product? With markups? I believe this is the correct store: https://www.aliexpress.com/store/1101346048?spm=a2g0o.detail.1000007.1.39ba1278GI1rXG

 

[TNT]

Will it work with macOS?

//

 

[IVX]

to be honest I use the link from the website or ask my wife, Sunny, for the link
https://e1dashz.wixsite.com/index/buy
DD, Linsoul, and maybe somebody else, are resellers.
APU PCBA assembling is still not finished due to mess around switches, so nobody is selling it but only Sunny. Actually, I am afraid to give resellers so special instrument as APU. I don't want if APU will buy accident buyers and ask me next what is it?

 

[capslock]

That's what I do, too I have ordered through your Aliexpress shop several times before, and it was always the problem that when I used the search field of Aliexpress to search e.g. for 9038D, I wouldn't get your shop or individual products, only those from resellers, so I turned to using google or the link on your website.

Using google or your website, I now get to your shop, I get to your shop, see the pictures, but when I click on a product, it get the image above.

There seems to be something similar but slightly different (different message displayed) going on randomly for many other listings. We mused it might be due to an unresolved electric safety EU regulation but it pertains to totally passive parts like aluminum feet to mount a case on, too.

https://www.diy-hifi-forum.eu/forum/showthread.php?5808-Mich-nervt&p=326527&viewfull=1#post326527