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DGNOG UM22C

tune

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DGNOG UM22C 32bit/768KHz $116
There are many mysteries surrounding the audio interface DGNOG UM22C. Although the price is low, the chip used seems to be AK5552VN. It seems that no one has measured DGNOG UM22C so far.
 

DWPress

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Send one to @amirm, he'll add it to the pile of devices waiting to be dissected.
 

MaxwellsEq

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There are many mysteries surrounding the audio interface DGNOG UM22C
I googled it. I couldn't find any mysteries, let alone many mysteries. What an I missing?
 

L5730

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Seems like it is only available from AliExpress sellers.
A few videos from the same source DGNOG. Though there are videos from different people on YouTube with other models from this brand - they are not doing an in depth review anything like Julian Krause's.

The display looks nice. Maybe there isn't enough gain from the mic pres for dynamic mics?
The Air button looks to be inspired by Focusrite.
 

soundslike

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The interface shows promise but there were a few issues I noticed with it.. I am currently tinkering with mine and will post PCB pictures soon if members are interested. I would be really interested to hear what people think. The internals are very different structurally to other interfaces on the market at the moment.
 
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tune

tune

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Information from people who have actually purchased items is very valuable. I'm interested.
 

soundslike

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I am certainly not the most knowledgeable however there are a few things that stood out to me. Firstly the 48v is always active. The 48v button turns the mic input on and off but the voltage is always 48v. Now i think there is an "upgraded version" that addresses this that has come out recently. The noise floor is audible but certainly not pronounced. Recordings on it have been crystal clear however it is tricky balancing mic gain with the recording volume at times. It drives condenser mics well. As for line level inputs, well, I have worked out that it doesn't blow your gear up but that 48v causes lots of distortion. I ripped out the 48v power supply and am in the process of rejigging (butchering) this to 5v as that suits my current needs best. Wish I waited for the upgraded version to be quite honest.

Build quality is pretty good. Component selection is suspect as I have never seen the op amps it is using. They appear to be "4580 G238" which I assume is some sort of NJM or JRC 4580 knockoff. The volume is a little odd in that turning the knobs lets you go up an down digital steps but unfortunately you cannot fine tune within said steps. I wonder about the USB interface part too, I would love to know more about it, but it is hidden. The drivers are "SXW T-ASIO_0429A_ASIO20230307" if that means anything. They work on both windows and mac. You get only one "Line in" for recording and one "headphones" for playback. It sounds quite good, and i am impressed for the money. But I am still going to end up buying a Topping 2x2 in future.

Apologies for the rough photos, I grabbed these on the way out of the house this morning. I will get nicer ones tonight. There is nothing on the underside of the board components wise.
 

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OP
tune

tune

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Thank you for your information.
 

AnalogSteph

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It drives condenser mics well.
Which is not a major challenge per se. Are the opamps next to the mic inputs 4580s as well? Should be fine for condensers, but don't expect much in the dynamic mic department.
As for line level inputs, well, I have worked out that it doesn't blow your gear up but that 48v causes lots of distortion. I ripped out the 48v power supply and am in the process of rejigging (butchering) this to 5v as that suits my current needs best.
Lots of distortion? That's a bit odd, but I guess it would depend on the output. P48V short-circuit current is only about 4 mA, and I would expect the line-in portion to have several 10 kOhms in series so it would be a fair bit lower there (maybe around 1 mA). Before ripping out the phantom power, I would rather make some sort of external adapter with some maybe 100k pull-down resistors and about 22 µF 63-100 V coupling capacitors, + facing the input. There would be enough space for some coupling capacitors inside the unit by the looks of it, assuming you find a good place to tap into the line-in signal path (maybe at series resistors).

Interesting design for sure. I wouldn't be certain that the unit even has an analog input gain control, though a gain pot could be running over the edge connector of course. If it doesn't, they're using the dynamic range of the AK5552 ADC to make up for it (would that even work?). The output side must be using the DAC built into the ADAU1701, with U11 being the headphone driver. I'm not sure what exactly the MVSilicon BP1048 Bluetooth audio processor (DSP) is used for, which also seems to sport a DAC of its own though it's even more basic than the ADAU's.

It's a surprisingly barren-looking circuit board for an audio interface in any case. Some of the magic may be hiding on the secondary board that houses the encoders and stuff.
 
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