Vantec NBA-200U USB External 7.1 Channel Audio Adapter

[Timbo2]

I figured I'd post a brief review on the Vantec NBA-200U USB External 7.1 Channel Audio Adapter. I used to use a 2 input KVM to toggle between my gaming PC and my everyday personal machine. Right now my company has all of its employees working from home so I needed a way to add my company laptop into the mix as full time work on its tiny screen is no fun. This required the purchase of a 4 input KVM.

One of the big issues with doing this is sound. My speakers are an old analog Logitech 5.1 setup which requires analog out from the PC. When there were only two PCs I kept the surround channels attached to the gaming machine and switched the fronts only with KVM. Downside was the KVM added some noise, but we weren't doing critical listening with it. (I have a Topping D10 and an O2 attached for music.)

Upgrading to a 4 input KVM brought a dilemma. There were a few that were 4K and switched analog sound, but they are pricey. If you give up switching analog sound the price drops considerably. So I pondered for a while what to do and suddenly thought what about a 5.1 USB DAC? These inexpensive KVMs have a USB hub that switches to the active PC. So how about putting the DAC on that hub? I'm happy to report this DAC works great for just this purpose. Bonus for me is that the thing is so old that it is only a Class 1 audio device in Windows. This means my Win 7 work laptop to which is locked down and I can't add drivers recognizes the device with no additional drivers. So I now get 5.1 sound on all my devices and have eliminated the noise from the old KVM. All this for just for $25!

It's based on the CMedia CM6206 and available on Amazon in the US. My only minor complaint is the ridiculously bright blue LED that also blinks when the DAC is active. Fortunately I have it buried under the desk and can't see it.

 

[iMickey503]

Here is some Data from Daqarta on the chip. Not the same unit as the one featured in the above post, but the CM 6206 chip itself was on test in this unit:

Thanks to Daqarta Team author (Bob Masta) for doing the testing on this chipset and his findings. I have screen copied the relevant information to the C-Media CM6206 bellow that he tested. Please read the full article linked as it covers other things of interest WELL beyond my technical understanding.





SPECS AS TESTED for This Vendor/Unit/model/Version

About the unit itself excerpt from Daqarta (Please read the full test on link here as it covers other USB Sound cards)

Price: US $20

Dimensions: 5.0 x 2.5 x 1.0 inches.

Includes: USB cable, SPDIF TOSLINK optical cable, driver mini-CD.

Connectors: USB, SPDIF TOSLINK In, SPDIF TOSLINK Out, Mic(1), Mic(2), Line In, HP Out, F Out, SS Out, BS Out, C/B Out.

Controls: Record Mute button, Play Mute button, Vol Up/Down buttons.

This device is available from multiple suppliers. The actual manufacturer is not stated. You can locate a supplier by searching the Web for "USB 7.1 CH 3D External Sound Pocket" (without the quotes) and looking for a matching picture. Some distributors are Sabrent (model USB-SND8), TigerDirect, and USBgear.

Please note: This device has multiple manufacturers who typically use the same case and the same basic CM6206 circuit, but may use different circuit board layouts and different component values. The latter may affect the low-frequency input and/or output response, so your unit may differ from the values reported in the Comparison Table.

As with the above 5.1 channel device, this unit uses the C-Media CM6206 8-channel codec chip, only here all 8 channels are connected. The Front (Left and Right) output channels were used for all tests, marked F-OUT on the unit.

The unit comes with a driver mini-CD, which you should install if you are running Windows Vista or later. But if you are running Windows XP and using multi-channel (7.1) outputs, you may want to avoid that and just use the default driver that is installed when you plug in the USB connector. See the CM6206 5.1 and 7.1 Driver section above for details.

The overall low frequency response is excellent; the Line In -3 dB point is below 1 Hz.

One quirk of this unit is that the Left and Right channels are reversed from the normal "Red is Right" convention: Here the Right channel is the plug tip (white conductor) and Left is the ring (red conductor). This is true for both outputs and Line inputs, so it's not obvious in loopback testing.

Another quirk is that the two LEDs on top of the unit are mis-labeled: The green LED that is on continuously when USB power is supplied, and which flashes when the output is active, is marked "Record Mute". Conversely, the red LED that comes on when the Record Mute button is active is marked "Operation". (The Play Mute button does not stop the blinking of the green LED, however.)

Nevertheless, these buttons and the red LED can be convenient for some tests. You do need to be careful not to hit Play Mute accidentally, because there is no indication of its state; if you notice a lack of output after toggling an adjacent button, try clicking this button. (If that doesn't restore the output, click the button again... otherwise when you find the real cause of the missing output it will still be off.)

A nice feature of this unit is that there are separate Mic(1) (Right channel) and Mic(2) (Left channel) input connectors. Each is a stereo jack, with 1.25 Vdc electret microphone bias connected to the tip (white conductor) along with the signal.

However, on Windows Vista and later the stereo Mic inputs may not be enabled by default. Before starting Daqarta, right-click on the speaker icon in the system tray and select Recording Devices. You should see separate options for USB Microphone and Line inputs. You must disable Line before you can enable Microphone (and vice-versa). Select and enable Microphone, then click on Properties. Select the Advanced tab and change the default "2 channel, 16 bit, 44100 Hz (CD Quality)" to "2 channel, 16 bit, 48000 Hz (DVD Quality)". Click OK and you are ready to start Daqarta.

Note, however, that during performance testing there were two occasions where the Mic In signals seen by the unit inexplicably dropped to zero and stayed that way. Even after quitting Daqarta and unplugging the USB connector to remove power from the unit, upon reconnection and restart there was still no signal.

If this happens, open the system tray driver icon and click on the little speaker volume symbol near the upper center. Then click the Reset button that appears next to it... the Mic signal suddenly reappears. It's not at all clear what action provoked this behavior in the first place, but possibly plugging cables in and out caused the signal and bias to be briefly shorted. Presumably, in any stationary setup this would not arise.

The unit has a separate headphone jack marked HP-OUT, but it actually has a higher output impedance (31 ohms) than the F-OUT (7 ohms).

​

I have purchased the same unit as O.P. (Timbo2) 3 days ago. And would like to give you my initial impressions under Android.

First, It works in both 2 channel mode, and stereo microphone inputs. The Microphone inputs are very low, and I don't know how to make them louder. But they sound cleaner then the input on the devices that I have used as they do not have any sort of AGC used.

I can not detect any noise under normal operation. The buttons work fine under android. I did not try the line-in input. The Headphone jack is okay. It plays through this even with the speaker output is connected on android. Did not try to monitor the mic inputs will try that later.

I picked up this unit so I could use it as a active Crossover with a asus intel based Chromebox to see how it would work/sound compared to a dedicated Hardware unit typical in car audio use.

Sounds good to me out of the box. The headphone out sounds a bit weak. But only tested Briefly with Samsung earbuds. Not my good headphones. but I didn't hear any noise or outright Audible problems from this unit while in operation in 2 channel mode from my phone. (ZTE ZMAX Pro with STOCK drivers)

Open Camera had no problems detecting stereo Microphone inputs. They were low, but it was definitely left right stereo from Microphone input. Did not try line-in level input.

Unit worked plug and play out of the box. I was able to create a ground loop, but then could not with Battery powered USB Power brick.




There is a Linux command line utility for this chip on GitHub HERE.

Command line utility to control a CM6206 based USB sound card. Enables readout of all registers and enables control of special settings (e.g. internal mixer settings, SPDIF parameters etc.).

The program is made for Linux, but should be portable to Windows, if anybody would like to.

Data Sheets
https://www.datasheetarchive.com/Cmedia cm6206-datasheet.html


Using the SPDIF to record under Linux
https://linuxmusicians.com/viewtopic.php?f=19&t=10271


Portable Synth application of chipset with modification to the audio Output hardware mosfets

Rasberry Pie related use for SPDIF Mixer
https://www.vogons.org/viewtopic.php?f=62&t=74902&start=20


ODROID-XU Lite CM6206-LX USB 5.1 Sound Card On Android
https://forum.odroid.com/viewtopic.php?t=3013


Moode Audio player related info for chipset with Raspberry Pie post on DIYA
https://www.diyaudio.com/forums/pc-based/271811-moode-audio-player-raspberry-pi-347.html

And the few videos on the unit are just people using it with windows. Nothing special or technical of any real value other then unboxings I can find.

Info here is more for me as I plan to use this for my Linux crossover on chrome/ Android project.