My WiiM Amp tests, chapter 2

[canard]

I know that you were referring to reported cases in general, but you also counted me in, although I had no such experiences.

my poorly translated written expression... etc.
(This shows that there were different cases of problems on these first series)

Things seem to be returning to normal, that’s the main thing
(and we should find more or less the classic characteristics of small amplifiers based on this chip)
;-)

 

[mikesas]

So in a nutshell my first batch Amp will sound less good and I should return it
for a new WiiM batch model ?

I can also confirm that to my ears, my first batch and replacement units both sound great. I could not perceive any difference in sound quality. However my conclusions should be taken with the following understanding:

• I do not claim to have “audiophile ears”
• I was not using the sub out
• My amp is hidden in a cabinet where I cannot hear the humming unless I open the door and stick my head in the cabinet

I only replaced it because the humming is still not right even if I can’t really hear it where I had it installed normally and I have no idea if the humming would possibly impact the life of power supply.

And finally, yes it is not great that WiiM launched the AMP “before it was ready,” but I applaud WiiM for their transparency here and response to correct the situation. I am a customer (Pro Plus & AMP) because WiiM listened to the early feedback to add Squeezelite and thrilled to have support for another option in the LMS ecosystem.

 

[Smartplug]

I think if the user is concerned about measurements whether they going to hear between the new or old is up to them to decide if they want to exchange it. They can get good night sleep if they know that their amp is the latest ver 5.

 

[Brantome]

in the precise case of the machine tested by onlyoneme we were not in the case of a slightly disappointing machine or just the quibblers by observing the measurements (certainly it is only a minisystem) found fault, but of a broken machine. ..
as a reminder there have been cross
-cases of noise...
-of extreme heat ...

Describing it as “extreme” heat is a bit extreme surely? It was perhaps initially warmer than desired, but in my experience it didn’t veer into “hot” territory and certainly not where it would burn you if touched.

-more serious: reboot following contact and "electrostatic shock" (yourself)...

What I said was related as here: ”I noted with interest in Darko’s article that he mentioned the “static” apparently killing the amp. I experienced similar and wondered whether I’d fried my test unit when I was swapping speakers”, so no “shock” which would normally imply self injury, but a static discharge potentially killing the unit. But as you’ll note, I was unjudicially swapping speakers when the unit was only in standby rather than fully powered off which might better explain why the amp died.

counterfires like "nothing is heard" "nothing seriously".... "just a few machines" (while reading the forums we can see that there are many problem cases") we were rather counterproductive...

My very early unit didn’t hum unless I had my ear almost touching it and even then if I hadn’t been asked to do that, I wouldn’t have noticed it all. Nor do I have it on a desk in front of me where I might notice it if it were any louder - I have it on a shelf with my amp and other kit, a good 2-3m away, like others do. So, yes criticise me for always asking about audibility, but I‘d have enough to worry about if I heard an issue without worrying about the things I (and possibly others) don’t hear

I also wonder how many users would have noticed the hum had they not read about it in forums? While there are mentions of the hum in a handful of Amazon customer reviews, they don’t seem as prevalent as they would appear to be in the forums - guess the forums have a different type of user base…

just 4 reviewers frequenting here (out of 4? ) and having received machines from wiim we had some problems...onlyoneme darko archim and yourself...statistically...that's out of 4...not bad right?

Yeah, quality control and pre production testing do need improving as it’s not great that reviewers get units that do have issues that should have been identified much earlier. But as you say, things are being addressed…

Cheers

 

[mikesas]

I also wonder how many users would have noticed the hum had they not read about it in forums? While there are mentions of the hum in a handful of Amazon customer reviews, they don’t seem as prevalent as they would appear to be in the forums - guess the forums have a different type of user base…

Funny that you mention that as I did not hear the hum at first either. Interestingly, it was your comment about the unit feeling warm that made me curious to check how warm mine felt. I think I actually felt the hum with my hand resting on the top of the unit before I actually heard it and that was also before I read about the hum.

But your point is well taken. I am sure there are plenty of customers from the first batch that did not notice the hum and not reading the forum. However, I also will note that I have not seen anyone speak up that their first batch unit is without any hum once inspected like we now hear with Ver 5 units. But admittedly, I am also not following the forum as closely as you are so please do correct me if I am mistaken as maybe somebody had in a different thread.

 

[Brantome]

However, I also will note that I have not seen anyone speak up that their first batch unit is without any hum once inspected like we now hear with Ver 5 units.

I have a very early test unit and I could barely hear anything untoward with my ear almost on the unit. It’s been running now for a couple of months and I honestly can’t hear anything now - don’t know if I’m deafer or it’s settled down for whatever reason…

 

[Smartplug]

Because of this incident, wiim ultra may go longer before its release to ensure quality released.

 

[DavidGriffiths]

Describing it as “extreme” heat is a bit extreme surely? It was perhaps initially warmer than desired, but in my experience it didn’t veer into “hot” territory and certainly not where it would burn you if touched.

I reported extreme heat as in almost too hot to touch. But:

• the Amp was inside a cabinet
• it was not going into standby at the time so this was after being on for hours in an enclosed space

Since placing it outside the cabinet I've had no problems with it getting hot.

On the other hand:

• it may not have been in standby but hadn't been recently used when I observed it running hot
• there are other devices in the cabinet - Sky Q box (and before that Sky HD) and Xbox - and they never get hot

 

[Smartplug]

I reported extreme heat as in almost too hot to touch. But:

• the Amp was inside a cabinet
• it was not going into standby at the time so this was after being on for hours in an enclosed space

Since placing it outside the cabinet I've had no problems with it getting hot.

On the other hand:

• it may not have been in standby but hadn't been recently used when I observed it running hot
• there are other devices in the cabinet - Sky Q box (and before that Sky HD) and Xbox - and they never get hot

What pcb version you have?

 

[DavidGriffiths]

What pcb version you have?

"PCB_version": "4"

 

[gorman]

Received my unit in early January, from Amazon Italy.

Read about coil whine and I recorded with my smartphone what can be heard, very faintly, from about 30-40cm of distance (younger people might hear it from farther away, I don't know).

I amplified the recording a lot, in order to make it clearly audible. Mine is PCB version 4, I have till early February for a refund. I'm not sure what I should do, to be honest. If the noise indicates a faulty unit, I wouldn't want to keep it. Especially if it could mean trouble farther ahead in time.

 

[Smartplug]

Received my unit in early January, from Amazon Italy.

Read about coil whine and I recorded with my smartphone what can be heard, very faintly, from about 30-40cm of distance (younger people might hear it from farther away, I don't know).

I amplified the recording a lot, in order to make it clearly audible. Mine is PCB version 4, I have till early February for a refund. I'm not sure what I should do, to be honest. If the noise indicates a faulty unit, I wouldn't want to keep it. Especially if it could mean trouble farther ahead in time.

I had ver 2 which I just returned. I will wait for few months to ensure all all the pcb revision is final. Right now ver 5 is the current and who knows there maybe ver 6.

 

[pipomolo42]

-of extreme heat ...

To be fair, this one was actually only a software issue (CPU not entering sleep state), and was fixed by a software update

 

[Vladetz]

@onlyoneme
Really appreciate your work!
Are going to do some other measurements?

 

[onlyoneme]

Yes, but it's a time consuming process and I had to take a break unfortunately. More measurements are coming.

 

[mikesas]

I am sure there are plenty of customers from the first batch that did not notice the hum and not reading the forum. However, I also will note that I have not seen anyone speak up that their first batch unit is without any hum once inspected like we now hear with Ver 5 units.

For fear and balanced reporting…..

I just saw on the ASR thread a reference PCB v2 unit without any audible hum.

Post in thread 'WiiM Amp discussion'
https://audiosciencereview.com/forum/index.php?threads/wiim-amp-discussion.47096/post-1859504

 

[Brantome]

For fear and balanced reporting…..

I just saw on the ASR thread a reference PCB v2 unit without any audible hum.

Post in thread 'WiiM Amp discussion'
https://audiosciencereview.com/forum/index.php?threads/wiim-amp-discussion.47096/post-1859504

And I’ve mentioned my humless v2 here too…

 

[onlyoneme]

There was never a simple correlation between the pcb version and humming noise.

 

[harkpabst]

Maybe (or hopefully) there will be a zero hum correlation from PCB version 5 on.

In reality, it could come back at any later time, depending on quality variation of sourced parts.

 

[canard]

Maybe (or hopefully) there will be a zero hum correlation from PCB version 5 on.

In reality, it could come back at any later time, depending on quality variation of sourced parts.

of course and is essential in the future..
but if there are different generations of pcb it is because there is not only that... has already been the case with the "plus"