Seeking lower cost alternatives to Berkeley Audio Design Alpha USB converter

I am looking for a USB to optical audio converter.
The Alpha USB from Berkeley Audio Design is an external asynchronous USB to S/PDIF (or AES) interface. It's strictly a D to D converter accepting USB digital audio input and delivering digital audio output.
That's the type of product I'm looking for. However, at $1,895 the Berkeley Alpha USB is far more expensive than most similar products I've seen. Some of these products sell for less than $100.

I'm on a budget. Can anyone recommend one of the lower priced alternatives to the Alpha USB from Berkeley Audio Design?
@jgoldrick - as luck would have it, I just found a mint condition Singxer KTE SU-1 "Kitsune Tuned Edition" at a good price.
I have had good success with the Matrix Audio SPDIF. Thumbs up for build quality, SQ and value

good luck
A network bridge may be what you are looking for. Ethernet is inherently low noise and is the best way to get bits from a computer to a DAC. I have a Pi2AES on a Raspberry Pi which produces very low levels of both noise and jitter, spanking much more expensive DDCs.
This may be useful:
@pengun - the video you shared just turned everything I thought I knew upside down. Fortunately, I didn't know that much. 

However, I can't immediately go down the Ethernet, I2S path. As it stands now, my two best DACs do not have I2S inputs. 

In another post you said: 

> Just got a Denafrips Ares II. Its really good, a wonderful source for any digital system. 

That doesn't appear to have an I2S input either. Did you switch DACs? What are you using now? 

I learned a lot from the video you shared. GoldenSound makes a compelling case for using Ethernet and I2S instead of USB (or Bluetooth aptX HD). I'm also fortunate that my entire place is wired with cat-6.

However, until I can acquire the hardware that will let me use I2S everywhere, GoldenSound's comments about using a Raspberry Pi 3b+ caught my attention. However, this video does not explain the basis for his recommendation. Is he saying to replace your PC with a Raspberry Pi 3b+? If so, is the reason simply to get rid of GPU and other noise from a complex system? I already have a simple but powerful headless PC running Linux. It uses a server mb without any GPU. I'm not sure a Raspberry Pi gives me any advantage, and the video doesn't explain things well enough for a beginner like me.