Let's talk about the jitter over digital outputs. I will use the Holo Audio Spring 3 DAC which is a true NOS DAC and has an unique ability to turn off its PLL. This way I can compare a raw performance of the outputs in j-test.
Ultra, toslink:
![1722433651844.png 1722433651844.png](https://forum.wiimhome.com/data/attachments/9/9690-116f837c433bacb7f1d16c9d44764ffe.jpg)
Ultra, coaxial:
![1722433675466.png 1722433675466.png](https://forum.wiimhome.com/data/attachments/9/9691-0ec3a2e272fea52d537e1b112ff5d66b.jpg)
Pro, toslink:
![1722433697441.png 1722433697441.png](https://forum.wiimhome.com/data/attachments/9/9692-e22fc57c79ec20c128362f67ee891181.jpg)
Pro, coaxial:
![1722433717225.png 1722433717225.png](https://forum.wiimhome.com/data/attachments/9/9693-7e1117c004dd5ab479cb1f710da1a677.jpg)
Mini, toslink:
![1722433737842.png 1722433737842.png](https://forum.wiimhome.com/data/attachments/9/9694-1986e1bb4d6400050c5ef08209e0bd73.jpg)
Non-WiiM device for a quick comparison, SMSL PO100 Pro, coaxial:
![1722434305873.png 1722434305873.png](https://forum.wiimhome.com/data/attachments/9/9696-14e13b074880d4b304ee3aa75c3e5cbe.jpg)
All WiiMs have similar random jitter level, which is reflected by the noise floor, but they differ a lot with the periodic jitter, which is visible as symmetric spikes around the fundamental signal. The Mini is definitely the worst one.
Statements about the same, "perfect" quality of all WiiMs digital outputs are unjustified.
A disclaimer, as I didn't mention it yet - all these tests were made with 48 kHz test signal, which is commonly used for jitter measurements. Results may differ for higher sample rates which may be more problematic for toslink cables, especially lower quality ones.
For example, 192 kHz test case on the Pro, toslink vs coaxial:
![1722446584081.png 1722446584081.png](https://forum.wiimhome.com/data/attachments/9/9700-cb8ac10c1cc0e087357e7fa68fb6d2c5.jpg)
Coaxial output wins here.
Another example, 192 kHz again but the Pro vs the Ultra, both on coaxial outputs:
![1722448431034.png 1722448431034.png](https://forum.wiimhome.com/data/attachments/9/9702-3895e5df3d04832d7ebb2b53ed2a3873.jpg)
The advantage of the Ultra is more visible.
Ultra, toslink:
![1722433651844.png 1722433651844.png](https://forum.wiimhome.com/data/attachments/9/9690-116f837c433bacb7f1d16c9d44764ffe.jpg)
Ultra, coaxial:
![1722433675466.png 1722433675466.png](https://forum.wiimhome.com/data/attachments/9/9691-0ec3a2e272fea52d537e1b112ff5d66b.jpg)
Pro, toslink:
![1722433697441.png 1722433697441.png](https://forum.wiimhome.com/data/attachments/9/9692-e22fc57c79ec20c128362f67ee891181.jpg)
Pro, coaxial:
![1722433717225.png 1722433717225.png](https://forum.wiimhome.com/data/attachments/9/9693-7e1117c004dd5ab479cb1f710da1a677.jpg)
Mini, toslink:
![1722433737842.png 1722433737842.png](https://forum.wiimhome.com/data/attachments/9/9694-1986e1bb4d6400050c5ef08209e0bd73.jpg)
Non-WiiM device for a quick comparison, SMSL PO100 Pro, coaxial:
![1722434305873.png 1722434305873.png](https://forum.wiimhome.com/data/attachments/9/9696-14e13b074880d4b304ee3aa75c3e5cbe.jpg)
All WiiMs have similar random jitter level, which is reflected by the noise floor, but they differ a lot with the periodic jitter, which is visible as symmetric spikes around the fundamental signal. The Mini is definitely the worst one.
Statements about the same, "perfect" quality of all WiiMs digital outputs are unjustified.
A disclaimer, as I didn't mention it yet - all these tests were made with 48 kHz test signal, which is commonly used for jitter measurements. Results may differ for higher sample rates which may be more problematic for toslink cables, especially lower quality ones.
For example, 192 kHz test case on the Pro, toslink vs coaxial:
![1722446584081.png 1722446584081.png](https://forum.wiimhome.com/data/attachments/9/9700-cb8ac10c1cc0e087357e7fa68fb6d2c5.jpg)
Coaxial output wins here.
Another example, 192 kHz again but the Pro vs the Ultra, both on coaxial outputs:
![1722448431034.png 1722448431034.png](https://forum.wiimhome.com/data/attachments/9/9702-3895e5df3d04832d7ebb2b53ed2a3873.jpg)
The advantage of the Ultra is more visible.
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