Thanks, really low , but thats a good thing . Should easily drive at least two poweramps from each RCA output.
Really high class preamps seems to have lower output impedance than 100 Ohm . Nice !
Last edited:
My Ultra tests
- Thread starter onlyoneme
- Start date
Really high class preamps seems to have lower output impedance than 100 Ohm . Nice !
I'm tired already my Padawan, I need to restNow, can you measure If there is any dc offset on the RCA outputs , obi-wan ?
The force is strong within you Obi wan , youre allowed to rest now.I'm tired already my Padawan, I need to rest
Give the legend 6 pack and he will return twice stronger the following day.
Obi-wan, I salute you and look forward to the offset measurements on the RCA analog output
You have pmI'm tired already my Padawan, I need to rest
steadyshot
Major Contributor
- Joined
- Mar 14, 2023
- Messages
- 823
What if someone uses in the eu version another (after market) c7 power cable? Would you observe anything different in the measurements?
You are so impatient, my Padawan. I can no longer teach you.You have pm
Can someone measure DC offset from RCA analog output on the Ultra ?
Some of us ( like me ) use power amps without DC protection ( i.e. Hypex ncore ) . I want to know if there is any DC on the analog rca output for the Ultra. Can someone measure this ? Onlyoneme ?
forum.wiimhome.com
Sorry for my ignorance: Are the frequency responses for phono inputs ok? Shouldn't those be flat from 20 to 20,000 khz?It's going to be a long time process, but I will try to add a new content periodically. Everything based on the pre prod device which is PCB ver 2 unit.
Just one thing at the beginning, a comparison of the waveforms over the digital coax output, tested with the oscilloscope and 192 kHz sample rate test signal, and terminated at 75 ohms.
This is for the Ultra:
View attachment 8954
And this is for the Pro/Plus:
View attachment 8955
Ideal and perfect waveforms would show rectangles. In the real world it should be as close as possible to the ideal one. The Ultra is a clear winner here.
A rough comparison of the Pro Plus with the Ultra, THD vs frequency, 192 kHz sample rate. It's not a THD+N, so it's not a sinad. And this is over the analog output using full scale sine signals.
View attachment 8971
The "hills" here would require some explanation, but I'll spend some time on that a little later with my personal perspective on other measurements results which I've faced.
Few words on the noise on the analog output. I use 192 kHz sample rate and a dithered silence file to keep the output active.
First result is taken when the Ultra is connected directly to my ADC, screen is off:
View attachment 9045
and with the screen on:
View attachment 9046
10 kHz component (and harmonics) appear.
Now the same test but also with the scaler, so that's the setup I use most of the time, screen off:
View attachment 9047
and the screen on:
View attachment 9048
One of the differences between above setups is the input impedance, 1.2 kOhm vs 100 kOhm. I've made some additional tests with RME UCX II and 5 kOhm and 9 kOhm impedances, and observed results lied between these above, being closer to the ADC alone with its low input impedance. I guess that the noise pollution from the PSU is strong enough to reveal itself when high impedance input is used. And it can affect measurement results.
Personally I prefer to see something as below, the Pro Plus powered by an LPS and with the scaler, so high impedance input is used:
View attachment 9051
As I am still suspicious, I made another test with the LPF (which I use for class D amps measurements) attached. The scaler is used again:
View attachment 9052
Noise pollution is highly attenuated, so maybe it comes from the high frequency noise made by the PSU. I looked at the spectrum of white noise to verify how the DAC filter (there are 7 of them BTW) handles is. Below a comparison with the Pro Plus:
View attachment 9053
It doesn't look good to me.
And something for those sinad addicted, with an LPF:
View attachment 9065
and without it:
View attachment 9066
Noise level is 5 dB higher without the LPF so sinad is worse by 5 dB as well. Jitter artifacts are visible around the fundamental on both graphs.
For all the following tests I will use the LPF, unless stated otherwise.
The Dynamic Range, 120.1 dB.
View attachment 9361
THD vs level, for 1 kHz test tone:
View attachment 9375
IMD vs level, for SMPTE test tone:
View attachment 9376
A small sign of ESS hump is visible. I said in the comments, based on quick tests, that it wasn't visible with the LPF, but I was wrong.
J-test for the analog output. I've no idea why some people take such results as jitter measurements of the digital outputs...
View attachment 9377
NID multitone:
View attachment 9378
Time for something I would call a noise profile, over the coaxial output. I use both ADC Cosmos and the Scaler plus the LPF, with a termination at 75 ohm just before the LPF. Due to the LPF characteristics I limit the recording sample rate to 96 kHz. As a test signal I use dithered "silence" file.
First result comes from SMSL PO100 Pro, powered by the USB hub:
View attachment 9443
Next one is the WiiM Pro, powered by Sbooster LPS:
View attachment 9444
And the last one is the Ultra, powered by its internal SMPS:
View attachment 9445
The Ultra is a clear winner with its 583 uVrms noise level, but PSU spikes reveal the strongest presence. Noise of the WiiM Pro - 2.288 mVrms - is much higher although the linear power supply is used.
Low-level -90.31 dB signals look worse then for the Pro Plus.
Undithered, 16 bit:
View attachment 9560
The same but 24 bit:
View attachment 9561
Even the LPF doesn't let reach the Pro Plus level, although without it results are much worse.
The same signals but for the Pro Plus:
View attachment 9562
View attachment 9563
Intersample peaks are handled well, no LPF this time.
View attachment 9565
Even peaks at +3 dBFS do not result in clipping, there is enough analog headroom to handle it.
The latest firmware promises jitter improvements. And it improved indeed (j-test for the previous FW can be seen somewhere above in this post):
View attachment 9622
A progress is visible also for 1 kHz test tone (graph with the previous FW was shown for the sinad measurement somewhere above):
View attachment 9623
Well done @WiiM Team @WiiM Support .
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.
Toslink:
View attachment 9674
Coax:
View attachment 9676
Toslink is slightly better in case of the Ultra when the presence of periodic jitter is considered.
And USB output which is unfair for the comparison of course, because it's clocked by the DAC:
View attachment 9677
Spring 3 has incredibly low jitter.
All 3 graphs on the same screen:
View attachment 9681
Let's look how the jitter suppression works. A coax output but the PLL is on:
View attachment 9678
The jitter suppression of Spring 3 is extremely good, as far as I know it's one of the best available on the market.
Time for a "torture" test. I will use 192 kHz j-test signal to verify if cables matter. The Holo Audio Spring 3 in action again, PLL is off.
Mogami 2964:
View attachment 9778
Hosa BNC WordClock cable:
View attachment 9779
No serious difference for these coax cables. Time for optical ones.
A random one I used for jitter tests already, but I found out it's labelled as "Bandridge":
View attachment 9780
WiiM cable delivered with the Ultra:
View attachment 9781
Hosa OPM-303:
View attachment 9782
Well, time to change my own opinion, toslink cable matters
Of course the final result depends on the DAC and its ability to suppress the jitter.
WiiM cable but PLL is on:
View attachment 9783
And Mogami coax, PLL is on:
View attachment 9784
Results are very close when PLL is turned on.
Quick measurements related to analog inputs - ADC performance. Noise profiles first, inputs shorted. Everything sampled at 96 kHz.
Line-in:
View attachment 9997
Phono, MM:
View attachment 9998
Phono, MC:
View attachment 9999
And THD/sinad graphs vs the level in Vrms. The Pro Plus worked as the signal source, at 2 Vrms level for the line-in and at 200 mVrms for the phono.
Line-in:
View attachment 10000
Quite similar to the Pro Plus performance.
Phono, MM:
View attachment 10001
Phono, MC:
View attachment 10002
And frequency responses for phono inputs.
Phono, MM:
View attachment 10003
Phono, MC:
View attachment 10004
Time for the headphones output. I'm lazy so only 32 ohm load was tested. And a remark - the line-out voltage level affects also the headphones output so all tests were made with the line-out voltage set at 2Vrms. Max output level was 2.22 Vrms.
The output impedance is probably 40 ohm, so it's really high and not exactly best suited for low impedance cans. I will probably repeat my measurements in the future but using 300 ohm load.
An idle noise graph first.
View attachment 10008
This output seems to be also affected by the PSU noise.
Sinad test, first without the LPF:
View attachment 10009
and the same, but with the LPF:
View attachment 10010
The result is affected mostly by harmonic distortions, but the noise level is visibly elevated when the LPF is not used.
I will use the LPF for following tests.
I just reached the limit of attachments allowed, so I will continue in the comments.
A quick view on the sub out:
And that's all, I guess.
After few listening sessions I think I could fall in love with the Ultra although these PSU noise spikes irritate me a lot.
Here is the RIAA phone EQ curve. You'll note there is a 40 dB swing between 20 Hz and 20,000 Hz. Bass is suppressed and highs boosted when making the LP, and then an inverse curve is applied for playback. The phono input test referenced for the Ultra looks to reasonably match the red playback line shown below.
This thread mainly deals with objective measurements. Pick the one from the first post fitting your use case. In contrast to some other known review community, no fixed assumptions are employed regarding what might and what might not be perceivable under all sorts of different circumstances.
There are other threads dealing with very personal subjective listening expressions.
You might have to compare yourself - however , the PEQ function in the Ultra ( very transparent sounding ) is the real gameshanger making most speakers sound better . Also , the digital volume control in the pro and ultra are very good sounding . Might be important if used as a preamp.
