yes all ceramic decoupling caps removed in the end
i think i tried just removing the larger ceramics first and that prompted removal of the bypass
often i would find that if i use lifepo4 in most applications any cap certainly above 1uf seems to slow like a sponge on the end of a hoze and will cause a dulling of the sound loss of clarity, detail, bass definition and articulation of fast transients
the vref is hypersensitive and small changes are clearly audible
im of no doubt if we did something that worsened noise at the shift registers it would be blatantly obvious in any sort of listening test
i think i tried just removing the larger ceramics first and that prompted removal of the bypass
often i would find that if i use lifepo4 in most applications any cap certainly above 1uf seems to slow like a sponge on the end of a hoze and will cause a dulling of the sound loss of clarity, detail, bass definition and articulation of fast transients
the vref is hypersensitive and small changes are clearly audible
im of no doubt if we did something that worsened noise at the shift registers it would be blatantly obvious in any sort of listening test
I just took delivery of my DAM1021 rev. 3.0 and as promised I would post a photo. Things that are clearly different between this and the picture featured on the Soekris website are:
1) Larger power supply caps > 1000uF rather than 820uF
2) Additional MLCC caps > C168 through C177
3) Large enough holes next to new MLCC caps that allow for caps to be soldered
4) Six transistors, Q1-Q6 on the output, I'm assuming for muting
5) OnSemi 3.3V regulator, lower noise than previous one
6) Switching regulator circuit reworked, large flyback diode
7) Added LED D5
8) Added D4, (zener)diode array, logic gate?
9) Added U40, MOSFET?
1) Larger power supply caps > 1000uF rather than 820uF
2) Additional MLCC caps > C168 through C177
3) Large enough holes next to new MLCC caps that allow for caps to be soldered
4) Six transistors, Q1-Q6 on the output, I'm assuming for muting
5) OnSemi 3.3V regulator, lower noise than previous one
6) Switching regulator circuit reworked, large flyback diode
7) Added LED D5
8) Added D4, (zener)diode array, logic gate?
9) Added U40, MOSFET?
Attachments
Thanks for the nice pic!
1) Power supply caps became 1000uF in Rev2.
4) Q1 & Q2 existed since Rev1, Q3+ were installed in Rev2.
7) LED D5 was always there.
I believe that the missing resistors are due to the custom resitor values that Soren managed to procure.
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No its not, and this circuit is also used in v2. Haven't needed muting circuit since. The only noise at poweroff is a slight click if anything.
Sören, make the links work!!
http://soekris.eu/shop/pdf/tmp/dam1021-02: 0.02% resistor version rev3_0_english.pdf
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http://soekris.eu/shop/pdf/tmp/dam1021-02: 0.02% resistor version rev3_0_english.pdf
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I've had a DAM 0,02% rev 1 board laying around for ages and I'm finally starting to think this might be the time to start the project. I have been going trough the threads here at diyaudio since I was following the thread quite a lot in the beginning but then work and other stuff took all my time so I had a lot to catch up with.
My basic setup is this:
-DAM rev1 0,02 %
- Salas BIB for power 12 V
- DiyinHK USB 2 i2s
- ReflectorD for powering DiyinHK module
- Hifiduino/Dimdim's code & arduino & LCD for controlling
Seems like there are loads of new mods that could be implemented, but I find it rather difficult to decide which mods to do since there are so many variations. So far I think that I shall be doing the firmware update and the power off POP mod with resistors. Is there any other easy ways of getting rid of the POP sound during startup and power off?
Secondly, I was thinking about doing the "factory mod" for the board. Are there any other "must do" mods that I should consider? Or other mods that would be superior to the factory mod?
My basic setup is this:
-DAM rev1 0,02 %
- Salas BIB for power 12 V
- DiyinHK USB 2 i2s
- ReflectorD for powering DiyinHK module
- Hifiduino/Dimdim's code & arduino & LCD for controlling
Seems like there are loads of new mods that could be implemented, but I find it rather difficult to decide which mods to do since there are so many variations. So far I think that I shall be doing the firmware update and the power off POP mod with resistors. Is there any other easy ways of getting rid of the POP sound during startup and power off?
Secondly, I was thinking about doing the "factory mod" for the board. Are there any other "must do" mods that I should consider? Or other mods that would be superior to the factory mod?
My ref.3 board generates even louder click compared to previously used ref.2 board when sample rate is changed (change from 44 or 48 to 96k gives the loudest click) - any idea why muting isn't working in that case?
tia
Ulli
The jfets are for power up/down muting only, sample rate change is handled all digital in the firmware, and firmware is the same for both rev2 and rev3.... Sure you don't have other changes, like USB interface or player software ?
But the new firmware to be released soon should have the muting improved, more detection logic added there, was a little hard to get good muting between PCM and DSD, especially as the bclk stayed the same on my USB interface....
Yes. Just replaced rev.1 with rev.3 in my DEQX. Winfried has similar issues with DAM1021 in his DEQX - might turn out the DEQX is the culprit; no idea yet how to prove check this...
Anyway, looking forward to get new firmware with improved detection logic for muting.
BTW: DAM1021 now sounds great - thanks!
Ulli