WiiM Amp Ultra: Performance Meets Precision

canard · 2025-06-25T00:05:38-0700

For the future discussion regarding hardware...

Post in thread 'WiiM Amp Ultra: Performance Meets Precision' https://forum.wiimhome.com/threads/wiim-amp-ultra-performance-meets-precision.7167/post-133096

How is the thermal performance of the ultra amp managed? (In a compact format, this is a sensitive subject)

In the future, even if it may seem surprising at first...will external power supplies be considered to save space in machines, mainly for amps??
(And also for durability... power supplies are generally one of the main weak points...)

Why is there no proper headphone output for "all-in-one" products...??

is it planned to invest a little in engineering to improve the ana inputs and the ADC in the future??

(Balanced and dual sub outputs on future stream/preamps?)

Without constantly rushing towards the top of the range...will revisions/re-readings be considered for entry-level models... "mini", "pro plus", etc. "devices without a screen"... ???

But above all: How will Wiim handle future product names after such already pretentious names?

;-))

dominikz · 2025-06-25T00:30:50-0700

RyanWithWiiM said:
Glad to see so much excitement for the Amp Ultra! I'm going to be sitting down with the product manager soon to ask some questions I've taken from the community. If there's anything people would like to know, please ask here and I'll try to include some of the best ones!

Thanks! Id be interested in the following:

What is the sustained maximum power of the Amp Ultra (playing wide bandwidth signal over a few minutes), and can the thermal management protect the amplifier under such thermal stress?
Has there been any effort to address the typical rise of THD with frequency that is common to TPA3255 amplifier implementations (including Amp and Amp Pro)?
Has there been any change in the analog input (ADC) performance compared to Amp Pro?
Is "Room Fit" just renamed existing "Room Correction"?

Mr Ee · 2025-06-25T05:02:27-0700

PADave said:
I found the ultras to be better in several ways in side by side listening:

- more authoritative bass
- imaging was slightly better

Agree.

Wiimer said:
the Ultra gives a much clearer perception of each individual note.

Agree.

Along with a few others, I've had the amp ultra for a couple of weeks now
Here are a couple of snaps.

In the first one its in my maIn system, hooked up to my Paradigm Founder speakers along with an ultra (optical) -> vibelink combination.
The amp switcher is to the left of the amp ultra, which is in the middle.

In this 2nd one it's in my office setup, along with the amp pro and a switcher box.

My completely subjective summary, with words that I hope convey meaning without being too flowery.
The amp ultra is cleaner, clearer, more dynamic and more precise than the amp pro.
The amp pro sounds flatter, muffled, dampened, muddied compared to the amp ultra.
I think this explains the "imaging was slightly better" and "clearer perception of each individual note" comments by others above.
The music was just fuller / richer / more engaging with the amp ultra, and the amp ultra sounded better even at lower volumes than the amp pro.

The extent to which these differences were apparent did depend on the music / system. In my office setup, on some tracks I found these differences to be quite small while on others it was quite pronounced.
However, in my main setup the amp pro simply failed to convey any sense of life or dynamics in any music - everything I played was dull.

AndrewC said:
I am considering purchasing either the WiiM Amp Ultra as a standalone product or the combination of the WiiM Ultra + Vibelink Amp.

Obviously just my experience / observation, but I cannot tell the ultra (optical) -> vibelink and amp ultra apart at all.

dominikz said:
What is the sustained maximum power of the Amp Ultra (playing wide bandwidth signal over a few minutes), and can the thermal management protect the amplifier under such thermal stress?

Can't answer that directly, but I can say that I've run the amp ultra at 80-100 (depending on track's recording level 100 is just a tad too loud

) for at least an hour with no issues.
Yes, I was home alone...

And to answer another question, no EQ or RC enabled anywhere for this.

Ronnie D · 2025-06-25T05:19:49-0700

Mr Ee said:
but I cannot tell the ultra (optical) -> vibelink and amp ultra apart at all.

Thank you for this information @Mr Ee

canard · 2025-06-25T05:47:56-0700

Do we have to wait for the vibelink "mk2" with 2 TI chips now?

Wiimer · 2025-06-25T05:53:03-0700

Mr Ee said:
Agree.

Agree.

Along with a few others, I've had the amp ultra for a couple of weeks now
Here are a couple of snaps.

In the first one its in my maIn system, hooked up to my Paradigm Founder speakers along with an ultra (optical) -> vibelink combination.
The amp switcher is to the left of the amp ultra, which is in the middle.
View attachment 23178

In this 2nd one it's in my office setup, along with the amp pro and a switcher box.
View attachment 23179

My completely subjective summary, with words that I hope convey meaning without being too flowery.
The amp ultra is cleaner, clearer, more dynamic and more precise than the amp pro.
The amp pro sounds flatter, muffled, dampened, muddied compared to the amp ultra.
I think this explains the "imaging was slightly better" and "clearer perception of each individual note" comments by others above.
The music was just fuller / richer / more engaging with the amp ultra, and the amp ultra sounded better even at lower volumes than the amp pro.

The extent to which these differences were apparent did depend on the music / system. In my office setup, on some tracks I found these differences to be quite small while on others it was quite pronounced.
However, in my main setup the amp pro simply failed to convey any sense of life or dynamics in any music - everything I played was dull.

Obviously just my experience / observation, but I cannot tell the ultra (optical) -> vibelink and amp ultra apart at all.

Can't answer that directly, but I can say that I've run the amp ultra at 80-100 (depending on track's recording level 100 is just a tad too loud ) for at least an hour with no issues.
Yes, I was home alone...

And to answer another question, no EQ or RC enabled anywhere for this.

So when are you release your Kindle book? I've been waiting a year already

adias · 2025-06-25T07:28:26-0700

Mr Ee said:
...
However, in my main setup the amp pro simply failed to convey any sense of life or dynamics in any music - everything I played was dull.

I recall that clearly. I remember you tried both setups carefully to confirm. I concur - I have the amp pro in a tertiary system and it’s ok for very casual background music. I look forward to hearing the Amp Ultra in the same setup.

PADave · 2025-06-25T08:57:11-0700

Wiimer said:
You need a body armor and a helmet when discussing sound impressions here!

Now, this is just my subjective opinion, but I, like you, noticed a difference in the bass. Measuring the sweeps coming from the bookshelf mid-woofer, both gave the same response. However, when music was played, I could feel a difference. Also, the Ultra gives a much clearer perception of each individual note.

Again, this is my subjective opinion. Please do not use it as a reference. Please hear for yourself.

Yes, the bass was definitely better. My speakers sounded more punchy and you could actually feel it. Higher SPL for sure. I thought the speakers were loose in the ceiling at one point but it was the windows rattling. Part of it might have been the better synchronization between the two Amp Ultras with all four ceiling speakers in the area- I think something was off wrt timing on the two Wiim Amp Pros previously.

Burnside · 2025-06-25T09:15:17-0700

Erin’s review

canard · 2025-06-25T09:51:42-0700

Burnside said:
Erin’s review

It's funny...
A French expression...
see "the bottle half empty or full"..

It remains a rather efficient approach, but sensitive to the load in the "audio frequency zone".

Burnside · 2025-06-25T09:54:24-0700

canard said:
It's funny...
A French expression...
see "the bottle half empty or full"..

It remains a rather efficient approach, but sensitive to the load in the "audio frequency zone".

Well if I understood his graphs, was he not talking in the order of 0.4/5 of a dB for some frequencies? Would you really notice that when playing a piece of music compared to a test load?

canard · 2025-06-25T09:57:14-0700

Burnside said:
Well if I understood his graphs, was he not talking in the order of 0.4/5 of a dB for some frequencies? Would you really notice that when playing a piece of music compared to a test load?

Simple... Out of curiosity, played at 0.5dB with the peq offered by your Wiim..
"your own little experience"

( I have my answer ;-) )

slartibartfast · 2025-06-25T10:34:15-0700

canard said:
Simple... Out of curiosity, played at 0.5dB with the peq offered by your Wiim..
"your own little experience"

( I have my answer ;-) )

Your room definitely will not be within 0.5dB over the full frequency range.

dominikz · 2025-06-25T10:40:27-0700

Wide bandwidth (i.e. low-Q) resonances of 0,5dB (and probably even less) can absolutely be audible with certain content.

However, we should not forget that all amplifiers are load-sensitive to some extent - this is simply a consequence of the unavoidable voltage divider circuit between the source (amplifier's output) impedance and the load (loudspeaker) impedance. For those interested, I wrote before about this in e.g. this post on ASR.

One way to reduce this load-sensitivity is by designing amplifiers with as low as possible output impedance - but output impedance will never be zero so the amp will always be at least somewhat load sensitive.

We should also note that the amp is not load sensitive in the "audio frequency zone". It is load-sensitive everywhere - it is just that the "complex" load in Erin's test has an impedance dip between 200-300Hz (link to impedance responses of the two loads used by Erin) resulting in a corresponding voltage dip due to the simple voltage division effect mentioned above.

You will note a very similar load sensitivity result in Erin's review of the Vibelink Amp - though it looks a little bit less severe; at least in part due to different vertical scaling of the graphs in the two reviews.

I took the time to digitize measurements of both amps and here's how they look when shown on the same vertical scale:

Not looking as different anymore, right?

All in all, I'd say Amp Ultra is looking pretty good so far - but I'm still hoping someone will release a more complete set of measurements!

Steve Woodhouse · 2025-06-25T10:42:11-0700

canard said:
Simple... Out of curiosity, played at 0.5dB with the peq offered by your Wiim..
"your own little experience"

( I have my answer ;-) )

I believe, if someone asks you a question at an internet forum, you should tell them your answer, rather than just saying you have an answer.

Wiimer · 2025-06-25T10:51:15-0700

dominikz said:
Wide bandwidth (i.e. low-Q) resonances of 0,5dB (and probably even less) can absolutely be audible with certain content.

However, we should not forget that all amplifiers are load-sensitive to some extent - this is simply a consequence of the unavoidable voltage divider circuit between the source (amplifier's output) impedance and the load (loudspeaker) impedance. For those interested, I wrote before about this in e.g. this post on ASR.

One way to reduce this load-sensitivity is by designing amplifiers with as low as possible output impedance - but output impedance will never be zero so the amp will always be at least somewhat load sensitive.

We should also note that the amp is not load sensitive in the "audio frequency zone". It is load-sensitive everywhere - it is just that the "complex" load in Erin's test has an impedance dip between 200-300Hz (link to impedance responses of the two loads used by Erin) resulting in a corresponding voltage dip due to the simple voltage division effect mentioned above.

You will note a very similar load sensitivity result in Erin's review of the Vibelink Amp - though it looks a little bit less severe; at least in part due to different vertical scaling of the graphs in the two reviews.

I took the time to digitize measurements of both amps and here's how they look when shown on the same vertical scale:
View attachment 23191

Not looking as different anymore, right?

All in all, I'd say Amp Ultra is looking pretty good so far - but I'm still hoping someone will release a more complete set of measurements!

As always, very clear and excellent explanations

canard · 2025-06-25T11:06:36-0700

I just invite everyone to make their own experience...for their own practice, their requirements, their needs, etc., etc. That's all...and I'm not really here to influence...I'm not a prescriber.

peq of wiim can help for that s...

Burnside · 2025-06-25T11:10:03-0700

dominikz said:
Wide bandwidth (i.e. low-Q) resonances of 0,5dB (and probably even less) can absolutely be audible with certain content.

However, we should not forget that all amplifiers are load-sensitive to some extent - this is simply a consequence of the unavoidable voltage divider circuit between the source (amplifier's output) impedance and the load (loudspeaker) impedance. For those interested, I wrote before about this in e.g. this post on ASR.

One way to reduce this load-sensitivity is by designing amplifiers with as low as possible output impedance - but output impedance will never be zero so the amp will always be at least somewhat load sensitive.

We should also note that the amp is not load sensitive in the "audio frequency zone". It is load-sensitive everywhere - it is just that the "complex" load in Erin's test has an impedance dip between 200-300Hz (link to impedance responses of the two loads used by Erin) resulting in a corresponding voltage dip due to the simple voltage division effect mentioned above.

You will note a very similar load sensitivity result in Erin's review of the Vibelink Amp - though it looks a little bit less severe; at least in part due to different vertical scaling of the graphs in the two reviews.

I took the time to digitize measurements of both amps and here's how they look when shown on the same vertical scale:
View attachment 23191

Not looking as different anymore, right?

All in all, I'd say Amp Ultra is looking pretty good so far - but I'm still hoping someone will release a more complete set of measurements!

@RyanWithWiiM - maybe another request when you meet the Amp Ultra’s product manager, a set of measurements like what was produced for the Vibelink questions?

harkpabst · 2025-06-25T12:53:42-0700

As usually, Erins review is way above average compared to what you typically find on YouTube. He really delves(*¹) into it. It's great to see he really knows about all the goodies WiiM include in their software and hardware.

From a technical point of view, I think he's wrong about why he couldn't get a higher average SPL than 88 dB in his listening position. I bet that this is not due to a lack of power. 200 W are 200 W and would typically mean an average of 10 to 20 W, which would be incredibly loud, indeed(*²). It's rather a lack of gain, or more precisely a lack of gain to compensate for a low input signal. I have yet to see a single TV HMDI ARC output that would come even close to 0 dBFS peaks. All the units I have seen so far would max out at something <= -10 dBFS. This is not enough to have the WiiM Amp Ultra put out the power it is capable of.

The result is the same, of course. HDMI ARC might simply not get as loud as you want to. Unless you are willing to compensate for this using pre-gain. Personally, I am.

dominikz said:
Wide bandwidth (i.e. low-Q) resonances of 0,5dB (and probably even less) can absolutely be audible with certain content.

I won't contradict, at least not universally. Just two additional remarks to put things into perspective.

Few manufacturers of speaker drivers will provide you with drive units (woofers, tweeters, no difference) matched to tolerances any tighter than ±0.5 dB unless you spend crazy money for matched pairs. And it's sooo easy to lose one dB of efficiency, even over a broad range.
There is a great interview with legendary mastering engineer Bog Ludwig published by "Produce Like A Pro" on YouTube. Everyone should watch at least a couple of minutes of this interview, starting at timestamp 22.10. He mentions how incredibly superior digital mastering is regarding EQ, being able to adjust things down to 1/10 of a dB (sic!). But he also explicitly explains how amazed he was that few exceptional artists (presenting the Indigo Girls as an example) could reliably tell a 0.2 to 0.6 dB EQ setting apart. And that's the artists themselves, in a studio environment, listening to their very own stuff. I honestly believe that it takes extremely well trained ears to be capable of this.

So, it's certainly not impossible that 0.5 dB can make a perceivable difference. But generally speaking, no, our hearing is not "infinitely sensitive", neither to deviations in the frequency response, nor to effects in the time domain. 0.2 dB at 250 Hz is more or less nothing.

dominikz said:
I took the time to digitize measurements of both amps and here's how they look when shown on the same vertical scale:

Great work, as always.

Footnote 1:
I just learned that according to some study carried out by the Max Planck Institute for Human Development, "delve" is a word typically used by AI systems based on large language models.

And humans (scientific researchers to be exact) are said to have picking up those terms used by AI systems. Well, I don't know, but I'm neither an AI bot nor a scientific researcher.

Footnote 2:
As has been noted elsewhere (maybe here, maybe on ASR) it's quite a good rule of thumb to assume that the in-room SPL generated by a pair of speakers at ~3 m distance is pretty close to the rated anechoic sensitivity at 1 W 1m. So, a pair of his ARIA EVO X N ° 2 really shouldn't require much more than an average of 1 watt or 2 to deliver this 88 dB SPL.

Mr Ee · 2025-06-25T17:30:37-0700

harkpabst said:
It's rather a lack of gain, or more precisely a lack of gain to compensate for a low input signal

Yes, we already discussed this 'privately'.

This is why I wrote I was playing the amp ultra at 80-100.
Some might recall (unlikely) my 'what are you listening to' post about listening to Yazoo, Nobody's Diary on an amp, and how good it sounded.
That was the amp ultra, at 80, in my main setup.
For some recordings, although 100 was loud it wasn't ridiculously loud - the amp ultra ran out of puff / gain. Increasing pre-gain did increase the volume, but it didn't sound as refined.

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Key Features

Versatile Connectivity & Streaming

Smart Home Audio Control

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Pricing & Availability