[fuzun]

  Interesting that it can get a usable volume from 650s in low gain mode. I find that even with low resistance headphones, I seem to prefer the sound from mid-gain on this thing. The volume doesn't change much but the quality seems to change markedly for my SHP9500s and Status CB-1s, both of which are merely 32 Ohm.

 
I do not think setting gain to mid changes anything beside volume with shp9500.
 
But In my opinion bass boost makes shp9500 more accurate and musically more pleasant. What do you think with this regard?

 

[Vatnos]

The change is subtle but on certain tracks I am convinced it is there. I'll have a long listen tonight and get back to you.
 
I think there's an additional sweetness to the mids.
 
I'm with you on the bass boost for the SHP9500s. In fact that was the reason I got this amp in particular, because it has a really good bass boost. There's no mid-range bleed. The bass boost brings the SHPs closer to where I think they should be. There are occasional songs where I prefer to have it off, but 70% of the time I keep it on.

 

[Holypal]

Agreed. The bass boost here will not change the sound into bass monster. Just good enough, brings up the bottom smoothly and doesn't effect the mid range.

 

[neog007]

xduoo and burson, a great match so far

 

[fuzun]

Why no one takes photo of ground pins' connected area (need all black xd-05 but would be nice for comparison if you have silver xd-05)? Is the area scratched and scraped for connectivity?
 
There is ground issues in silver xd-05 in my opinion. I described this at my previous posts.
 
Ground pins: There are 3 ground pins(?) I saw. They are small golden pins and they are spring-supported. In silver xd-05; only 1 of 3 is ok. Others are connected to non conductive areas.

 

[Hansolo76]

  Why no one takes photo of ground pins' connected area (need all black xd-05 but would be nice for comparison if you have silver xd-05)? Is the area scratched and scraped for connectivity?
 
There is ground issues in silver xd-05 in my opinion. I described this at my previous posts.
 
Ground pins: There are 3 ground pins(?) I saw. They are small golden pins and they are spring-supported. In silver xd-05; only 1 of 3 is ok. Others are connected to non conductive areas.

 
I don't have any pictures of that from when I upgraded to my Burson V5i.  I can say that all the areas where the pins would make contact to the outer housing, in my black XD-05, the anodizing had been scraped off for a better contact point.  I noticed it on the front plate, back plate, and center housing piece.
 
I hope that helps. 

 

[Sladeophile]

Powering my new crack with this little beast. I just love its versatility! Great purchase for me!

 

[fuzun]

   
I don't have any pictures of that from when I upgraded to my Burson V5i.  I can say that all the areas where the pins would make contact to the outer housing, in my black XD-05, the anodizing had been scraped off for a better contact point.  I noticed it on the front plate, back plate, and center housing piece.
 
I hope that helps. 

Yes it should be like that. However, mine silver xd-05 does not have scrapes at back and front. They probably thought that silver parts are conductive. The problem is that, they actually are not!
 
Center housing is black for every xd-05 and I think all xd-05 s center housing is scraped. The problem is with back and front of silver xd-05.

 

[Phoniac]

However, using USB, the filters don't work

 
At least one who noticed it. I have put a comment on Massdrop about firmware bugs of the XD-05, and someone recommended to post my findings here as well. The unit behaves differently between USB and digital input SPDIF:
 
Fed via USB: PCM 1 and 3 are Short Delay Sharp, PCM 2 and 4 are Short Delay Slow. Changing from PCM 1 to 2 'Slow' is activated for less than half a second, then the unit activates Short Delay Slow. The same happens when switching from PCM 4 to 1, 'Sharp' gets active for less than half a second.

Fed via SPDIF: Short Delay Sharp is active all the time, no matter what is selected. Here also other filters can be seen for a very short time after switching through PCM 1 to 4.
 
Whatever else you thought you heard was just imagination. My unit is new, and the simple proof that all units behave like this ever since can be found on a russian website which hosts lots of XD-05 measurements. They show the exact same (wrong) impulse responses for the filter types with PCM 1 to 4.
 
http://reference-audio-analyzer.pro/en/report/dac/xduoo-xd-05-pcm1-spdif.php
http://reference-audio-analyzer.pro/en/report/dac/xduoo-xd-05-pcm2.php
http://reference-audio-analyzer.pro/en/report/dac/xduoo-xd-05-pcm3.php
http://reference-audio-analyzer.pro/en/report/dac/xduoo-xd-05-pcm4.php
 
But there is more. I have to add the SRC feature as buggy as it also shows a flaw. Playing back 44 kHz with SRC off, it seems the SRC is not off. The signal at the analog output includes high-frequency distortion which is not normal and should not be there. This is immediately solved when using the SRC, so upsampling to 192 kHz as standard operational mode for listening to SPDIF is recommended.
 
Now I don't want to send back this unit as it is a real bargain and working quite well in most other aspects. But I do want those sloppy chinese developers to show responsibility and fix these problems by a firmware update!
 

44 kHz playback via SPDIF
 

44 kHz playback via USB, or using SPDIF with upsampling

 

[Holypal]

At least one who noticed it. I have put a comment on Massdrop about firmware bugs of the XD-05, and someone recommended to post my findings here as well. The unit behaves differently between USB and digital input SPDIF:

Fed via USB: PCM 1 and 3 are Short Delay Sharp, PCM 2 and 4 are Short Delay Slow. Changing from PCM 1 to 2 'Slow' is activated for less than half a second, then the unit activates SD Slow. The same happens when switching from PCM 4 to 1, 'Sharp' gets active for less than half a second.


Fed via SPDIF: SD sharp is active all the time, no matter what is selected. Here also other filters can be seen for a very short time after switching through PCM 1 to 4.

Whatever else you thought you heard was just imagination. My unit is new, and the simple proof that all units behave like this ever since can be found on a russian website which hosts lots of XD-05 measurements. They show the exact same (wrong) impulse responses for the filter types with PCM 1 to 4.

http://reference-audio-analyzer.pro/en/report/dac/xduoo-xd-05-pcm1-spdif.php
http://reference-audio-analyzer.pro/en/report/dac/xduoo-xd-05-pcm2.php
http://reference-audio-analyzer.pro/en/report/dac/xduoo-xd-05-pcm3.php
http://reference-audio-analyzer.pro/en/report/dac/xduoo-xd-05-pcm4.php

But there is more. I have to add the SRC feature as buggy as it also shows a flaw. Playing back 44 kHz with SRC off, it seems the SRC is not off. The signal at the analog output includes high-frequency distortion which is not normal and should not be there. This is immediately solved when using the SRC, so upsampling to 192 kHz as standard operational mode for listening to SPDIF is recommended.

Now I don't want to send back this unit as it is a real bargain and working quite well in most other aspects. But I do want those sloppy chinese developers to show responsibility and fix these problems by a firmware update!



44 kHz playback via SPDIF



44 kHz playback via USB, or using SPDIF with upsampling

From the plots, PCM 2&4 are clearly different from PCM 1&3. If 2&4 only activate less than a second, how to measure the difference?

For SPDIF signals, I always use 192kHz sampling rate. So it's ok for me.

 

[davedm]

   
At least one who noticed it. I have put a comment on Massdrop about firmware bugs of the XD-05, and someone recommended to post my findings here as well.

 
That would be me. I am interested in this DAC+AMP after positive reviews. So I am intrigued as to whether the issue is software related or implementation related.

 

[Phoniac]

From the plots, PCM 2&4 are clearly different from PCM 1&3.

 

Exactly what I wrote. What is the intent of your comment?

 

 

 

If 2&4 only activate less than a second, how to measure the difference?

 
I didn't say so. I wrote that the missing two filters, Short and Sharp, get only activated for a brief moment when changing the PCM mode via the button. Then the wrong mode becomes active again, so one ends up with only two different filters available instead of four when using USB. With SPDIF it is only one. And obviously a DSO shows the impulse response in real-time so it is easy to see that the filters get activated and then changed again.
 
Based on the available documentation filters 3 and 4 are the intended ones, 1 and 2 are wrong in USB, and filters 1/2/4 wrong in SPDIF mode. The manual versus reality:
 
Mode USB
Display      Manual                   Reality
PCM 1       Sharp                     Short Delay Sharp   
PCM 2       Slow                      Short Delay Slow     
PCM 3       Short Delay Sharp    Short Delay Sharp
PCM 4       Short Delay Slow      Short Delay Slow

 

[Holypal]

Exactly what I wrote. What is the intent of your comment?

 

I didn't say so. I wrote that the missing two filters, Short and Sharp, get only activated for a brief moment when changing the PCM mode via the button. Then the wrong mode becomes active again, so one ends up with only two different filters available instead of four when using USB. With SPDIF it is only one. And obviously a DSO shows the impulse response in real-time so it is easy to see that the filters get activated and then changed again.

Based on the available documentation filters 3 and 4 are the intended ones, 1 and 2 are wrong in USB, and filters 1/2/4 wrong in SPDIF mode. The manual versus reality:

Mode USB
Display      Manual                   Reality
PCM 1       Sharp                     Short Delay Sharp   
PCM 2       Slow                      Short Delay Slow     
PCM 3       Short Delay Sharp    Short Delay Sharp
PCM 4       Short Delay Slow      Short Delay Slow

Sharp and Short Delay Sharp isn't that different. And you can't see it in frequency response. Please have a look at the FR plots in AK4490 document. The two Sharp filters have the same:
https://www.google.no/url?q=https://www.akm.com/akm/en/file/datasheet/AK4490EQ.pdf&sa=U&ved=0ahUKEwi_-KrihZLRAhUCDywKHbWoARoQFggaMAA&usg=AFQjCNH9IrTUdY1X17r5NPuRnsB1nYz4cw

 

[Phoniac]

Sharp and Short Delay Sharp have the same frequency response, but very different impulse responses. Same with Slow. Look at the impulse responses on the AKM website (or some posts ago in this thread). Also both Slow and Sharp have linear phase over their whole bandwidth, while SD are IIR filters and such have phase shift.
 
From an audio perspective the best filter from these four is Sharp, as it has reduced pre- and post ringing, perfect frequency response, and no phase shift within the audio band. And excactly that filter is advertized but not available due to a control bug in the unit.

 

[Holypal]