Distortion with Ultra line out to B&K power amp

[harkpabst]

Continued here:

https://forum.wiimhome.com/threads/...ortion-since-5-2-715362-firmware-update.7105/

 

[harkpabst]

Since your other thread didn't yield any satisfactory results you could send feedback to WiiM directly through the WiiM Home app: More => Feedback

Your report will also include device logs, which WiiM can use to make sense of the behaviour.

 

[QuarryHunslet]

Both threads have now been merged.

 

[RWB]

Did that include setting the line input resolution to 24 bit 96 kHz (instead of 192 kHz). If not, please make sure to give that a try, too. Measurements have shown worse performance of the ADC at 192 kHz (wether in the audible range or not), but this behaviour could change between firmware versions.


Definitely worth it. Power cycling is completely harmless. You don't loose any settings (in contrast to a factory reset) but sometimes is needed to cure issues that appear after a firmware update.

Last question: Did you happen to apply any form of EQ to the line input?

Power cycle did help but hasn't eliminated the problem completely. CD's with exceptional dynamic range such as Telarc's still have issues on the transients where there's a lot of energy. Still present with line out set to 200Vrms and EQ set to flat. I will try a reset later today.

 

[RWB]

Both threads have now been merged.

Thanks and that makes sense.

 

[Wiimer]

The CD player via line-in was not an issue until the latest firmware update.

This may not be related to your problem, but if you have the latest FW version of Ultra installed, I would recommend reverting the WiiM app back to the previous version (3.2.0) .
Please try reinstalling the WiiM app.

 

[harkpabst]

I will try a reset later today.

Trying 24 bit 96 kHz first would potentially make some sense.

 

[RWB]

This may not be related to your problem, but if you have the latest FW version of Ultra installed, I would recommend reverting the WiiM app back to the previous version (3.2.0) .
Please try reinstalling the WiiM app.

To be clear you're saying instead of reseting the hardware, first delete the app on my phone and reinstall it? If I uninstall the app how would I revert it back to 3.2.0? Wouldn't the new download be the latest version?

 

[RWB]

Trying 24 bit 96 kHz first would potentially make some sense.

That's certainly easy enough to do. You're thinking that too high of a bit and sampling rate might be working against me? I believe non-super audio CD's are 16/44kHz native but that's my memory from years ago.

 

[slartibartfast]

To be clear you're saying instead of reseting the hardware, first delete the app on my phone and reinstall it? If I uninstall the app how would I revert it back to 3.2.0? Wouldn't the new download be the latest version?

At least for Android, 3.2.1 was withdrawn.

 

[canard]

Checking the actual output level of your CD seems to be one of the first things to do since it goes through an ADC conversion...if there is saturation it is merciless ;-)

but also from experience...if some have a fairly comparable version...it might be worth checking to see if a new firmware has messed things up...that's already been seen with Wiim regarding audio ;-)

48/24 is raisonnably enough ( or 96/24)
;-)

 

[harkpabst]

That's certainly easy enough to do. You're thinking that too high of a bit and sampling rate might be working against me? I believe non-super audio CD's are 16/44kHz native but that's my memory from years ago.

In theory, this shouldn't make any difference at all. Anything from the lowest (16 bit 44 kHz, native CD resolution, indeed) to the highest (24 bit 192 kHz) should work equally well for playing music from any analogue source (like the output of a CD player, where the internal DAC already converted the digital signal).

In practice, things often tend to be a bit more tricky. It's just from experience in this forum that 24 bit 96 kHz gave the best results when 16/44.1 generated occasional clicks or pops or dropouts for whatever reason. Real world noise performance at 24/192 turned out to be worse then at 24/96 as show by measurements done by e.g. @onlyoneme.

The latter should not result in perceivable distortion, but since it's literally free to try ... why not?

 

[canard]

In theory, this shouldn't make any difference at all. Anything from the lowest (16 bit 44 kHz, native CD resolution, indeed) to the highest (24 bit 192 kHz) should work equally well for playing music from any analogue source (like the output of a CD player, where the internal DAC already converted the digital signal).

In practice, things often tend to be a bit more tricky. It's just from experience in this forum that 24 bit 96 kHz gave the best results when 16/44.1 generated occasional clicks or pops or dropouts for whatever reason. Real world noise performance at 24/192 turned out to be worse then at 24/96 as show by measurements done by e.g. @onlyoneme.

The latter should not result in perceivable distortion, but since it's literally free to try ... why not?

It's indeed trying, especially since 192k is of little interest, but even more so here with such a modest analog input...
we don't even expect a 16bit enob... it's not even the quality of a 44/16 here...
the discussion is a bit unreal 96..192... 24 bits
hihi

"192/24 theoric of adc chip... marketing that blinds"

could be locked in 44 or 48/24 in ana input.... would be much more judicious and monitorable for everybody
;-)

 

[harkpabst]

It's indeed trying, especially since 192k is of little interest, but even more so here with such a modest analog input...
we don't even expect a 16bit enob... it's not even the quality of a 44/16 here...
the discussion is a bit unreal 96..192... 24 bits
hihi

"192/24 theoric of adc chip... marketing that blinds"

could be locked in 44 or 48/24 in ana input.... would be much more judicious and monitorable for everybody
;-)

Most importantly, it should simply work, irrespective of resolution. If the CD output was really overdriving the input on the analogue side, no ADC setting could repair that afterwards.

 

[slartibartfast]

Most importantly, it should simply work, irrespective of resolution. If the CD output was really overdriving the input on the analogue side, no ADC setting could repair that afterwards.

Presumably the CD output is 2Vrms. If it also has a variable output it would be worth trying that but the Ultra should be able to handle 2V.

 

[kjell.bjornfors]

I've only had the Ultra for 2 weeks and everything worked fine until yesterday. I turned it on to do some room calibration and was prompted to perform a firmware update (5.2.715362) which I did. I'm now getting severe distortion only on the line-in where my CD player is connected. I connected the CD player to my old preamp and it works fine. Playing the same CD tracks on Amazon Music streaming through the ethernet port plays fine. Either a component failed on the line-in circuit or the firmware update screwed something up.

The distortion sounds like speaker voice coils hitting the backplate from over excursion but it's there at minimal volume where the speaker cones are barely moving.

Not eager to do a reset as I assume doing so will erase all my settings and preferences unless there's a way to store those.

Anyone else experiencing this? Any and all suggestions are appreciated.

Do You have rc and peq active? To high amplification at some frequency can make the signal hit the ceiling at transients.

 

[canard]

Most importantly, it should simply work, irrespective of resolution. If the CD output was really overdriving the input on the analogue side, no ADC setting could repair that afterwards.

I completely agree...my aside... off topic
my """It's indeed trying""

 

[RWB]

At least for Android, 3.2.1 was withdrawn.

I use an iPhone and it's also version 3.2.1. Hate to go through deleting, reinstalling and having to set everything up again and all my preferences if there isn't a decent possibility of it resolving the issue.

 

[RWB]

Checking the actual output level of your CD seems to be one of the first things to do since it goes through an ADC conversion...if there is saturation it is merciless ;-)

but also from experience...if some have a fairly comparable version...it might be worth checking to see if a new firmware has messed things up...that's already been seen with Wiim regarding audio ;-)

48/24 is raisonnably enough ( or 96/24)
;-)

The specs on the Rotel CD player indicate an output voltage of 0.5 peak to peak. I did try dropping the line-in to -10db but it didn't make any difference.

The Rotel does have a digital out that bypasses the internal DAC but it's a coax connection. I'd have to use a coax to optical converter and use the DAC in the Ultra which might resolve the problem but it's another component in the chain and a big reason for getting the Ultra was to simplify things as much as possible.

 

[RWB]

Presumably the CD output is 2Vrms. If it also has a variable output it would be worth trying that but the Ultra should be able to handle 2V.

The Rotel spec indicates the output is 0.5 volts peak to peak which I believe was pretty standard fo CD players of it's vintage (2001). I did lower the line-in level to -10db but it did not make a difference.