WiiM Amp Ultra with external DAC?

[Burnside]

If I recall, it was in a thread with lots of measurements and graphs, and I don’t think it was a frequent poster who did them…

I’ll search high and low too

 

[Mr Ee]

If I recall, it was in a thread with lots of measurements and graphs, and I don’t think it was a frequent poster who did them…

I’ll search high and low too

Yep, and I don't think it was the Ultra Noise Shaping thread, which I did find and discounted as the one I was really looking for.

 

[Burnside]

If you search for ADC and 24/96, there are a few comments saying 24/192 measured poorly in comparison and that 24/96 is to be preferred, but I’m still struggling to find the actual post…

 

[Mr Ee]

I did find some posts about the pro plus and ADC with poor 16 bit conversion, but also note that the issues were addressed with firmware updates.
e.g.

O

Post in thread 'My WiiM Pro Plus (+) tests'

Jul 31, 2023

Part 6 - ADC performance:

Analog in - digital out:

ADI-2 will generate a reference analog signal and E1DA Cosmos ADC will work as the reference ADC.
Due to the features of the RME DAC, audio chain for testing the Pro Plus ADC can be quite simple :
REW (PC USB out) > ADI-2 USB in > ADI-2 analog out > Pro Plus analog in > Pro Plus toslink out > ADI-2 toslink in > ADI-2 USB out > REW (PC USB in)

Resolution of the ADC is controlled by the relevant digital output settings of the Pro Plus. The maximum allowed resolution of 192 kHz / 24 bit will be used. For all the...

• onlyoneme

• 

Still, 192 is overkill, and why not choose 24 over 16.
Ipso facto 24 / 96 is best

 

[DazST]

Thanks for your efforts. I played around with bit rates over the weekend (analog, optical and usb inputs) but can't say that I could detect any audible differences in terms of sound quality. If the source was 16/44.1 (cd or flac file) would you expect any audible difference setting the maximum to 24/96?

 

[Mr Ee]

Thanks for your efforts. I played around with bit rates over the weekend (analog, optical and usb inputs) but can't say that I could detect any audible differences in terms of sound quality. If the source was 16/44.1 (cd or flac file) would you expect any audible difference setting the maximum to 24/96?

There have been a few people here who have reported / asked about poor sound when using the analog input and iirc these were all when the ADC was set to 16 / 44.1
It sort of seems logical to choose that when the source is from a CD player, but as mentioned above the fact that it was CD is completely unrelated / irrelevant to choosing ADC settings - you should choose the settings that work best in that particular device's ADC.
And it might be that all settings work equally well, or equally enough to not be noticable.
Given that there's no downside to choosing 24 bits, that there have been reports of issues at 44.1, and that 192 has been shown to be slightly noisier than 96 (there is a graph somewhere!, but is it enough to cause any noticable change?) then choose one and then forget about it.

As for the optical and usb settings you mention, these would be the max outputs.
Unless you external dac has an upper limit (e.g. some only support optica or usb up to 96khz) then I'd say set them to the highest values.
This means the wiim won't resample anything before sending it out to the dac.
Unless you chose the Fixed Resolution option?
Even then, will you hear a difference? Doesn't really matter what theory or anyone else has to say about it, I think you already have your answer on that.