E1DA Cosmos ADC

[Skj]

any idea of those frequencies in upper region ?

 

[IVX]

any idea of those frequencies in upper region ?

I recommend you REW FFT to measure the noise floor. You'll see something like this:

 

[IVX]

After a short discussion, I made some simple passive LPF with not too bad parameters. If anybody has interest to DIY that, you are welcome

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

DiAna has an exceptional visualizing ability and can work with this hardware. The passive notch is any essential start but not enough on its own.

www.diyaudio.com

 

[ChUmI]

My last upgrade - dual E1DA Cosmos A-iso setup in mono mode driven from Topping D90SE

not bed

 

[staticV3]

My last upgrade - dual E1DA Cosmos A-iso setup in mono mode driven from Topping D90SE

View attachment 335259

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not bed

Very nice!

121.7dB at the ADC should be close to 130dB at the DUT: Graph

Add a Cosmos APU and you'd have an analyzer that exceeds what even the APx555B can measure for 1k SINAD

 

[capslock]

Just out of curiosity, why does the ADCiso have typically 3 dB lower 3rd harmonic than the ADC classic, as mentioned by IVX a couple of pages ago?

About the low noise power pack Xiaomi PLM18ZM recommended by IVX, it does not seem to be available in Europe or is branded differently. It is listed on Aliexpress, but that shop does not ship it to Germany (btw, E1DA Ali shop also still does not ship to Germany, but to France).

What are people using in Europe instead of the PM18ZM? I was thinking may using an analog regulator fed from 2 Li-ion cells or a 12 V lead acid battery might even be better than a power pack with a switch mode converter? Is there a need to feed Scaler, APU and ADC from separate batteries or can they all use the same unit?

 

[IVX]

Just out of curiosity, why does the ADCiso have typically 3 dB lower 3rd harmonic than the ADC classic, as mentioned by IVX a couple of pages ago?

About the low noise power pack Xiaomi PLM18ZM recommended by IVX, it does not seem to be available in Europe or is branded differently. It is listed on Aliexpress, but that shop does not ship it to Germany (btw, E1DA Ali shop also still does not ship to Germany, but to France).

What are people using in Europe instead of the PM18ZM? I was thinking may using an analog regulator fed from 2 Li-ion cells or a 12 V lead acid battery might even be better than a power pack with a switch mode converter? Is there a need to feed Scaler, APU and ADC from separate batteries or can they all use the same unit?

I use a slightly modded frontend in ADCiso. Pls, try to search our discord regarding the powerbanks comparison, not too many but have some. Regarding the separated powerbank per unit, it is the best way to get the cleanest result, however, not necessary one, and it depends on your test room EMI conditions.

 

[capslock]

I use a slightly modded frontend in ADCiso. Pls, try to search our discord regarding the powerbanks comparison, not too many but have some. Regarding the separated powerbank per unit, it is the best way to get the cleanest result, however, not necessary one, and it depends on your test room EMI conditions.

Yes, discord. I used to read there but haven't in about one year. It's only a few days ago that I started looking at your products again. However, with the link, if first get an invite from you and when I click join it keeps telling me the invide cannot be accepted. It has been like this for about a week on different computers.

Edit: seems to be cookie related, as I don't get the message on a machine that I didn't have a yera ago. working on it.

 

[IVX]

Hmm, I tried right now this link, no problem..

 

[IVX]

BTW, we have over there one longplay case with the guy from NY who reported specific noise from all my products APU, Scaler. We tried to solve the issue for about 4 weeks until the user try these devices in another place and found no any noise at all It was a reply regarding the room EMI.

 

[capslock]

Hmm, I tried right now this link, no problem..
View attachment 338748

Well somehow on both of the computers that I had used previously, logging into plain discord and accepting their updated conditions of use did the trick. The link now works. Thanks

 

[swa2023]

I was waiting for the Cosmos Scaler because of the low input impedance of the Cosmos ADC, and while the Cosmos APU solves this issue for 1kHz signal, I wanted to measure IMD, Multitone, etc. I finally got the Scaler and did a quick test. Let me share the results.
https://www.audiosciencereview.com/...ts-and-measurements.37739/page-3#post-1328586

I measured two DACs with Cosmos Scaler and ADC (Grade B). One is TOPPING D30Pro (Balanced) which did not have any problem with the input impedance of Cosmos ADC. The other is an ES9023 based DAC board (SE), which had high level distortion at low input impedance. Below is a comparison of without Scaler, with Scaler 0dB, Scaler Auto and APU 1kHz notch (THD+N and 1kHz signal dBFS at 4.5V input range). The input range of Cosmos ADC was all 4.5Vrms, measured by Stereo mode of ADC (not MONO).
View attachment 308317

As you see, Cosmos Scaler reduced harmonics of the ES9023 DAC drastically. Without Scaler (Red) vs with Scaler 0dB (Green).
View attachment 308313

I was able to measure IMD (SMPTE 60Hz and 7kHz) either by 0dB or Auto settings of Cosmos Scaler.
View attachment 308315

While the Auto setting of Cosmos Scaler was unstable when measuring multitone. 0 dB (or fixed gain) worked fine.
View attachment 308316
I am satisfied with these results. Thank you @IVX for this nice variable gain input buffer.

Sorry to ask, does it mean APU preamp can't measure Sweep IMD, Multitone, etc?

 

[staticV3]

Sorry to ask, does it mean APU preamp can't measure Sweep IMD, Multitone, etc?

It can, but only with low amplitude input signals as the preamp cannot be set to unity gain, only +34 or +60dB.

 

[IVX]

maybe swa2023 was talking about the Notch section, then yes, it is impossible to use multitone.

 

[Bacek]

IVX​

Do you have any plans to add SPDIF output to ADC (officialy or by diy expansion)? I saw some attempts here to add it, but probably no one succesed with it.

 

[IVX]

I didn't think about it yet.

 

[oal]

Sorry to ask, does it mean APU preamp can't measure Sweep IMD, Multitone, etc?

As IVX answered correctly, the APU cannot be used for general multitone measurements. As stated in Cosmos APU's “Important notes”,
https://e1dashz.wixsite.com/index/cosmos-apu
there are four things the APU can do. a) measure THD+N at 1kHz or 10kHz with notch, b) measure DR/SNR with +34dB or +60dB preamp, c) rip vinyl with RIAA EQ d) use a Pro condenser mic with 48V power and preamp. I belive IVX did not design it for IMD or Multitone measurements.

 

[IVX]

right, but actually, not a big deal to reduce notch F from 10k to 7k(original 10nF + 4.3nF C0G), and increase the input RC HPF cutoff from 1.5Hz to 100-300Hz(replace Elna 10uF to C0G 22nF). After that, you'll get an unprecedented precision meter of IMD
PS: I just tried that and the trick doesn't work. APU needs an extremely high-Q notch to avoid affecting the intermods close to 7kHz. With/without 7kHz+300HzHPF IMD is the same -120db. I think, we can use the HPF only to dramatically reduce the ADC's IMD contribution(-120db in both cases, hence, Cosmos ADC residual IMD is much lower than 9039Q2M's IMD). The notch at 7kHz is useless, simply add a good quality 100nF in serial to Cosmos ADC inputs(reducing 60Hz for 20+db), and that's it.

 

[IVX]

I inserted into our short XLR cable 2pcs 100nF C0G Murata 1206(now it's an HPF 1st order with ADC's input impedance) to get a lower 60Hz IMD test tone, and got a difference of IMD about 10db vs standard cable.

 

[BKDad]

REW ought to be able to correct for the low frequency roll-off with a Cal File, so the display would look nicer.