The Fosis have a tad more power into 4 Ohms, and while the LF distortion is fine they also have about the worst HF distortion of any PFFB implementation of the 3255 (not sure what happened there, probably budget output coils). If you look at the two tone IMD test, -67 dB for the highest distortion component vs. -79.5 in the Ultra. Or 15 kHz THD+N that hits -55 dB in the single digit Watts vs. -61 dB at 15 W.
If you are ready to tinker there are solutions available even for raspberry pi along with DSP
Crossing over at 250Hz will affect imaging. That pretty much covers all of the bass range and lower mids including parts of vocal ranges.
I really hope wiim will consider stereo sub out or even proper 2.2 crossover
Have to disagree on the software part. I used to have a Yamaha NP-S303, and now I’m rocking a WiiM Ultra. WiiM’s software is much better—easier to use, more intuitive, less wonky—and the customer (and community) support is way better too. It’s clear that software is a core part of WiiM’s business, while for Yamaha it’s just one of many things they do.A Yamaha R-N303 with MusicCast that sold for $250 will beat this any day with a stable software, amplifier power, radio, phono and two set of speaker outputs. $280 more only for a fancy touch screen? Some might like the blings.
I’ll be replacing the Ultra and my old Yamaha amp with the WiiM Amp Ultra to streamline the setup and save space.
Still does not achieve the specified 100wpc @8Ohm and 200wpc @4Ohm?. And the measured power is the max I believe and no room for peaks beyond that? One of the drawbacks of WiiM's UI is they have not prioritized the processes of audio playback with the highest priority. Try changing the playback screen to one of the fancy VU meters and the audio will stop playing and many other menu functions will do the same... lol. A lot have improved from the earlier wiim mini s/w but nothing perfect yet.
A Yamaha R-N303 with MusicCast that sold for $250 will beat this any day with a stable software, amplifier power, radio, phono and two set of speaker outputs. $280 more only for a fancy touch screen? Some might like the blings
It is hard to deal with than class AB but it has been reduced in higher end products:
that is why he need a 2.2 sub, to tread it like a 2 way speaker with full dsp, not a Wiim. But that is a bit more complex to do it right
If "sound quality" is a concern I believe it is important to point out that music won't have the same level at e.g. 100Hz and at 10kHz - unlike the typical multitone signal which has same-level components at all frequencies:
It's mostly inherent to the topology. If you look at this graph, you'll see that the resonance of the amplifier's output LC filter is at 45-55 kHz. For all modern Class D amplifiers, this value fluctuates around 35-55 kHz. The 2nd and 3rd harmonics of a 15 kHz signal are 30 and 45 kHz, which is very close to the resonant frequency of the LC filter. Therefore, you simply have to accept the fact that Class D amplifiers only operate up to 20, maximum 25 kHz. Measurements of anything above these frequencies are have small sence and have little to do with sound quality.
It would be neat to see a one-off THD+N/SINAD vs. Frequency chart for a better comparison in that case, between two amps with comparable base dashboard SINAD (AHB2 vs NCx500 for example).It is hard to deal with than class AB but it has been reduced in higher end products:
Note that the issue shows up here because these amps have such low noise floors. A class AB may look cleaner but have much higher amount of noise which would hide that high frequency distortion.
So if I’m understanding correctly, my hunch was right, and limiting the measurement bandwidth to 20khz would practically eliminate the disparity in that particular graph.
I agree with you completely, but to play devils advocate, on this forum we consistently critique objectively poor performance, that will fall orders of magnitude below audibility thresholds, and on devices (I.E dacs) that are always followed by devices with orders of magnitude worse performance (speaker drivers), for systems that in 99.99% of rooms and listening levels, will have all audible noise+distortion masked by the ambient room noise floor.
This is a controversial issue. It's been raised on the forum more than once. It's a well-known fact that Hypex/Purifi amplifiers measure much better at high frequencies and multitone than the TPA3255. But they also cost significantly more. How important this is and how much one is willing to spend for personal peace of mind is up to each individual to decide. It's difficult to even discuss the audibility of all this due to the vast differences in experience, sensitivity, and musical standards among listeners.
Does that mean that if we use the EQ, room correction, HPF, we get the same performance measurements as you already measured?
What about usb out to a hp amp? Works great for me.
amirm, you need to measure the THD after aplying EQ.
EQ With Confidence: 200 Post-EQ Remeasurements Validate That Headphones Follow A Linear Response To Equalization
Headphones are much more linear and obedient to EQ than most people imagine. The match between the calculated curve and the real, post-EQ measurement is strikingly close.www.rtings.com
This story just makes me smile! As noted by many, it isn’t everyone’s cup of tea. But for many many people, it provides all-in-one audio beyond the limits of what was readily available just a few years ago. Perfect for people who only stream or maybe play CD’s occasionally. I just bought one to replace my TOPPING DAC and PA5 since my wife consented to add a sub to my KEF R3’s, and I think that the sub out with EQ will be fantastic. (The TOPPINGs will we relegated to a room sans subwoofer). Thanks for sharing her success!
It does. Just by reading in this forum you should have learned about how power measurements can differ depending on the boundary conditions.
Calling Yamaha's software "stable" is really the nicest euphemism one could come up with.
Not at all. This is not an EOL date. It's a legal requirement in some countries to provide such a list an WiiM are updating it from time to time. The date provided has just been updated from December 2026 to December 2029 some months ago. This means that even the <$100 Mini introduced in 2021 will receive software security updates for more than 8 years. Most probably the date will be pushed even further at a later point in time.
