Wiim Pro Measurements - the horror, the horror + crazed fanboi

So Lindsay and I did a video a while back about how horrible the Wiim Pro sounded here: https://www.superbestaudiofriends.org/index.php?threads/wiim-pro-streamer-review.14835/

with the video here:


If I could ask a favor from this community, please go the video and hit like / thumbs up. This is to provide balance to the Force. That is our least popular video and I know YT will punish it for not being liked. The wanted to try out the Wiim because it seemed awfully popular and many readers here asked for us to give our opinion. Well, we did, and the Wiim fanboys did not like it. From our perspective, our listening to it and crapping on it was a service to the audiophile community. The Wiim Pro's SPDIF coaxial output just sucked subjectively speaking. Since then, we've gotten hate, but also comments from others that the certain DACs had trouble locking into the Wiim Pro's SPDIF output. I decided to check out some measurements - the SPDIF output measurements.

Below is the SPDIF output. Unfortunately I forgot to grab the zoomed in square wave. After all, a bunch of square waves at 44.1kHz (or 48kHz, or whatever the sampling rate) is what the output is supposed to look like. Below is are square waves squished tightly together but zoomed out.



So what's the issue? The square waves are riding on top on another frequency! 60Hz and some harmonics to be precise! Not only that, the 60Hz harmonics is MASSIVE!

Give that the spec for the output level of SPDIF is supposed to be 0.5V peak to peak at most, no wonder some DACs can't lock on to the Wiim Pro's output. I bet many receivers are misinterpreting the Wiim Pro's SPDIF output because the 60Hz (+ harmonics) is "flipping" the bits!

 

So I plugged the SPDIF output into the analog input of the APx555 analyzer and set the bandwidth to 1MHz. This still isn't enough to make out the square waves, but at least we can analyze the noise spectrum better.

So what I found out is that the SPDIF output of the Wiim Pro was highly dependent upon the USB power plug. This was the worst example - using an Apple one. The noise, kind of a triangle wave at 60Hz, is almost 1Vpp!

 

This next one is better, it was a cheapo charger I found somewhere, probably from Amazon. Still about 300mVpp, not good because it's enough to trigger the bit flips in an SPDIF output.



Here is another one, but with music playing. The line is thicker because there are varying square waves (again can't be seen on the APx555 - we need a scope) embedded in the triangular 60Hz "carrier".

 

Finally, what is a decent SPDIF output supposed to look like? You can plug in almost any decent digital source, and the output is gonna look like this.



Yeah.

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Wiim Pro: the horror, the horror

Again, please go the video and click like on it. Don't let shills leverage YT to promote crappy products that both sound horrible and measure horribly. And yes, the company behind the Wiim knows how to play that game. And where is audio science when we really need it?

P.S. We tested two different units. Same result.

 

Yes. I can send you one. Going on vacation, but will send in two weeks.

 

Can you elaborate more as opposed to being cryptic with respect to the 75-ohm termination?

I used this cable with characteristic impedance of 75-ohms terminated BNC (measurement gear) and RCA (Wiim SPDIF output): https://benchmarkmedia.com/products/benchmark-bnc-to-rca-coaxial-cable-digital

Are you suggesting I should try another coaxial cable with RCA on both ends and cap it off with a 75-ohm BNC terminator such as this: https://www.sweetwater.com/store/detail/BNCTerm--pro-co-75-ohm-bnc-terminator

With the 75-ohm termination, did you attempt to try with a DAC to compare subjectively audio quality? The Wiim Pro manual didn't mention anything of this sort so I am not sure what you did. I would like to see if I can duplicate your findings.

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Also, please introduce yourself as this is your first post:

https://www.superbestaudiofriends.org/index.php?threads/new-members-introduce-yourself.11639/