The Zishan dsd's corner
Sep 24, 2019 at 9:45 PM Post #2,464 of 3,711
I can't remember which other thread that I was reading (Cayin or Shanling), but I believe it was mentioned that the EQ on those would only work on "standard" (CD quality) tracks, and not HD tracks, due to the processing power requirements.
Does anyone here know for sure that the Zishan DSD can apply EQ to HD (above 16-Bit/48-KHz) tracks?
 
Sep 25, 2019 at 2:02 AM Post #2,466 of 3,711
Yep, eq only works on flac, mp3
 
Sep 25, 2019 at 10:05 AM Post #2,467 of 3,711
Yep, eq only works on flac, mp3

Yep you are right, EQ works only with 16bit files.
I have found a workaround to have EQed music on the zishan without downsample everything and with a better equalization:
Build your HP equalization curve with RePhase (lower the gain before exporting), export it as a FIR filter (32/64bit float txt), then apply the convolution FIR filter to all songs with SoX. No need EQ if the files are already equalized :D
It's a good solution only if you use zishan with only a single pair of Headphones

I write an example below just in case someone wants to do the same.
Batch script for windows -> you drag on it all the songs and the result will be in "\converted" folder.

1st ex: import pcm file, upsample to 24/48 with max quality settings, apply convolution in 32bit float, export in flac
Code:
cd %~dp0
mkdir converted
FOR %%A IN (%*) DO sox -V4 -G -S %%A -b 24 "converted/%%~nA.flac" rate -v -s -I 48000 fir coeffs.txt
pause

2nd ex: import pcm file, apply 32bit float convolution, convert, apply noise filter and export in DSD64
Code:
cd %~dp0
mkdir converted
FOR %%A IN (%*) DO sox -V4 -S %%A -t dsf -b 1 "converted/%%~nA.dsf" fir coeffs.txt rate -vInt 2822400 sdm -f clans-8
pause

Enjoy :D
 
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Sep 25, 2019 at 5:10 PM Post #2,468 of 3,711
dumb question,
but I have the DSD Pro AK4497
I want to connect it via the Coaxial out to the Coaxial in of my XDuoo XD-05 but most coaxial audio cable don't have the 3.5 SE type plug.

What kind of cable can I use?
Just the standard 3.5 SE interconnect or something else I need?
 
Sep 25, 2019 at 7:48 PM Post #2,469 of 3,711
Sep 28, 2019 at 10:30 AM Post #2,470 of 3,711
Sometimes in my head grows some strange and crazy idea. First a pair of questions:
Has anyone written down a full schematic of the zishan dsd?
At what gain are set lpf opamp?

My main idea is to remove from the audio signal path everything after the LPF opamp, raise the power with a current buffer, BUT I need to know at what voltages the op275 are driving headphones, because if it is too low maybe a voltage gain stage is necessary. And keep only the balanced output, because atm i have only one pair of IEM and one of Full-size planars both with 2.5trrs jack. And the zishan power output is often not enough. After the project stage the main idea is to first use matrix board and then just order a custom pcb to put over the cleaned zishan pcb

@Ivan TT
 
Sep 28, 2019 at 3:19 PM Post #2,471 of 3,711
power output is often not enough
Try removing x4 output resistors on 2.5mm output, this may solve the issue.
I'm not 100% certain but I think LPF has gain of 2, but since the balanced output is bridged (borrowing the term from PA world) it's above my current level of understanding to predict the output voltage swing, sorry.
 
Sep 28, 2019 at 5:16 PM Post #2,472 of 3,711
@Draknodd
You can increase lpf gain (output voltage) if you want, you need to change the gain resistors.
zishan lpf has gain of 2, but ak4497 datasheet lpf uses a gain of 3:
https://www.head-fi.org/threads/the-zishan-dsds-corner.826185/page-106#post-14742034
Personally I didn't need more gain with my earbuds, so I didn't try to increase the gain.
If you want to change the balanced output after the lpf, I suggest to do it outside of the player in a separated circuit connected to the 2.5mm jack, then if you like the result you can implement it inside.
 
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Sep 28, 2019 at 6:59 PM Post #2,473 of 3,711
@Draknodd
You can increase lpf gain (output voltage) if you want, you need to change the gain resistors.
zishan lpf has gain of 2, but ak4497 datasheet lpf uses a gain of 3:
https://www.head-fi.org/threads/the-zishan-dsds-corner.826185/page-106#post-14742034
Personally I didn't need more gain with my earbuds, so I didn't try to increase the gain.
If you want to change the balanced output after the lpf, I suggest to do it outside of the player in a separated circuit connected to the 2.5mm jack, then if you like the result you can implement it inside.

Very smart advice to use jack as input for the testing circuit.
Resistors before jack already removed, still need more juice.
Unluckily my multimeter passed away :frowning2: need to buy a new one. Ideal would be 4volts at the output for my full size headphones. In these weeks I'll do proper testing.
Thanks for the advices :wink:
 
Sep 29, 2019 at 10:52 AM Post #2,474 of 3,711
So is the dsd still the best zishan or is the T1 better?
 

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