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The Zishan dsd's corner
Dec 19, 2020 at 6:50 PM Post #3,256 of 3,711
slavalun said:
@moshe tes!


You asked for a ready-made fee.
Universal subtractor-amplifier board for
DSD4497, DSD4497DUAL, DSD4499.







This board has been tested to maximize
possible results.

I can sell several ready-made boards to those who can supply it. The board will be built on one stereo amplifier!
All the necessary information for connection is on the board.
To anyone interested, please contact my personal mail.
Click to expand...

I assume from your statement, you are not interesting in selling a single unit? Also what is your personal email?
If by any chance you happen to accept single orders, is it possible to just get the board(s) with recommended part numbers for parts? I already have a few AD797 and LME49600.
 
Dec 19, 2020 at 9:28 PM Post #3,257 of 3,711
moshe tes said:
I thought about the impedance, but just ignored it thinking that the LPF op-amp ideally should have infinite impedance anyway. Of course assuming that basic concept applies to op-amps for all applications.
Click to expand...

There's the DAC output impedance, the opamp input impedance and also impedance changing with frequency, so there's a lot to consider to choose the filter impedance.
I'm sure "this wheel is already invented", it's clear a matter of studying and not guessing, something I'm not not going to do. :)
 
Dec 19, 2020 at 9:43 PM Post #3,258 of 3,711
Merlin-PT said:
There's the DAC output impedance, the opamp input impedance and also impedance changing with frequency, so there's a lot to consider to choose the filter impedance.
I'm sure "this wheel is already invented", it's clear a matter of studying and not guessing, something I'm not not going to do. :)
Click to expand...
I see your point. I figured that much after reading a little bit in the op amp section of the amazing “The Art of Electronics” book. There is a lot I still have yet to learn. A systems approach is essential in these matters.
 
Dec 19, 2020 at 10:03 PM Post #3,259 of 3,711
moshe tes said:
I assume from your statement, you are not interesting in selling a single unit? Also what is your personal email?
If by any chance you happen to accept single orders, is it possible to just get the board(s) with recommended part numbers for parts? I already have a few AD797 and LME49600.
Click to expand...


Obviously I have come up with a ready-made customized sound solution! I didn't offer a constructor!
I think we will not agree.
I am deleting my offer!
 
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Dec 22, 2020 at 1:53 PM Post #3,262 of 3,711
Setmagic said:
This how classic phase inversion looks like?
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@Setmagic yes if you inverse that should be the graph.
Setmagic said:
I removed 2 blue caps in ADIII but device can't turn on. So I placed them again and this time everything work.
IMG_20201214_194247240.jpg

It is other pair of caps blocking headphone output?
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GAD stated those caps (blue ones) are for power made by Philips. Doing inverse engineering you should know if you can change it for a greater value (I know it's so obvious) however, I think the caps in the output could be removed here is the translation of a listing:
Second, electronic components
1. The resistors used in the machine are all VISHAY wafer cylindrical resistors to ensure sound quality. The low temperature drift is 0.5%.
2. Volume control potentiometer, 09 type potentiometer.
3. Input coupling capacitor, Italian AV, Promise special capacitor
4. Power filter capacitor, Philips BC 5. This machine adopts an imported fever SYLVANIA 6021 double tertiary tube to amplify the signal, the internal resistance of the tube is very low, the amplification linearity is ideal, and the service life is long. The tone is clear and transparent, delicate and round, and the music is full of flavor.

Also in WAZE (a Facebook group) change the potentiometer for a Logarithmic one and maybe the white caps are for the opamp...
 
Dec 23, 2020 at 2:52 AM Post #3,263 of 3,711
Thak You @londere.
Looks like ADIII have inverted phase according to headphone out of my DSDs. First of all I must change it for proper way :)

In DSDs removing blocking caps in headphone out improve overal sound quality and base response. Where I can find this kind of caps in ADIII? I see this Italian VA cap is for input. And work in voltage grid of 6021 tube and I can't remove that?
 
Dec 24, 2020 at 11:27 AM Post #3,264 of 3,711
I have a Zishan Ak4499, and on charging I have found that the battery has swollen. I did charge through a slow charger so not sure what has happened. Is there any way that I can change the battery, and if so how easy is it. Thanks.
 
Dec 24, 2020 at 1:39 PM Post #3,265 of 3,711
Ghawke said:
I have a Zishan Ak4499, and on charging I have found that the battery has swollen. I did charge through a slow charger so not sure what has happened. Is there any way that I can change the battery, and if so how easy is it. Thanks.
Click to expand...
It’s easy only 2 pin the problem will be get the battery due measurements to be the same also try external battery chargers such as This
 
Dec 26, 2020 at 12:24 AM Post #3,266 of 3,711
hi everyone, i has been following this thread for a while, after reading you guy discussion, i had replace my zishan dual ak4497 buffer from op275 to opa1612, and the background noise quite dark, sub-bass is very deep also
49806309374ec7109e5f.jpg
 
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Dec 29, 2020 at 2:30 PM Post #3,268 of 3,711
Dec 30, 2020 at 11:18 AM Post #3,270 of 3,711
I kept checking the link, expecting something for the dsd, it gets confusing, seems a lot of people don't realize the dsd and the dsds are different
Glad I didn't try to install anything
We should figure out how to keep the dsd and dsds completely seperate. Would hate for someone to download wrong file and damage sometging
 
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