Welcome, Guest
Username: Password: Remember me

NOTE: This is a "Community" forum. Please be mindful that community members are here to help as part of a community effort. We therefore appreciate your effort in keeping this forum a happy place!

If you have a specific issue (e.g. hardware, failure) and want help from our support team, please use our tech support portal (Support menu - > Contact Us).
Thanks a lot of your help in making a better community.
  • Page:
  • 1

TOPIC:

C-DSP 8x12 External clock and linear power supply 3 months 1 week ago #54458

  • rsqt
  • rsqt's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Posts: 12
  • Thank you received: 0
Hello,

I would like to change the 24,576MHz clock to external clock with much lower jitter, a very good linear power supply from the 8x12 and also remove the switch psu for voltage from a high end linear power supply.

Does anybody know if it is possible to change the clock and which voltage should it have (3,3 or5V) and if it is possible to take another higher frequency

Which voltages do I need if changing the spsu? Only 15V or some additional?

I use the C-DSP not in a car and have several of them. I think it is such a nice DSP, easy to handle and small and so I would like to change something to get the BEST out of it. Some caps are just changed which makes the sound smoother.

Thank you for helping
Regards
Ralf

Please Log in or Create an account to join the conversation.

C-DSP 8x12 External clock and linear power supply 1 week 3 days ago #55653

  • shegl
  • shegl's Avatar
  • Offline
  • New Member
  • New Member
  • Posts: 9
  • Thank you received: 0
rsqt, yes I'm also would like to know how to make miniDSP clock run in slave mode with external master clock, plus would like to have i2s input over hdmi lvds or something like this too.
 

Please Log in or Create an account to join the conversation.

C-DSP 8x12 External clock and linear power supply 1 week 3 days ago #55654

  • rsqt
  • rsqt's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Posts: 12
  • Thank you received: 0
Hello,
dev team said to change 24,576 clock is possible. Opamps and spsu are not high end, too. These I want to change  and regulators for 1,8 and 3,3V.

Regards
Ralf

Please Log in or Create an account to join the conversation.

C-DSP 8x12 External clock and linear power supply 1 week 3 days ago #55657

  • shegl
  • shegl's Avatar
  • Offline
  • New Member
  • New Member
  • Posts: 9
  • Thank you received: 0
Hey, Ralf, what is you replacement candidate XO? Because first highend OCXO is DuCULoN and it is 45Mhz, it's costs alot.
However, which one exactly you going to change? As for me, I wish miniDSP could make a miniSHARC but with ADSP-21489 or ADSP-21594 with 10 SPORTS, with available switches to use external LRCLK. Anyway, I'm very interesting to know what tuning you will do and results.

Regards
Alex

Please Log in or Create an account to join the conversation.

Last edit: by shegl.

C-DSP 8x12 External clock and linear power supply 1 week 2 days ago #55679

  • rsqt
  • rsqt's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Posts: 12
  • Thank you received: 0
Hey Alex,

where do you live? I'm from Germany.
I bought a Sellarz and a Neutron Star 3 in 24,576 MHz. Dev Team said this is the only frequency that works.
The Sellarz (-172dB) is not so expensive, about $80 and really small. This clock is very good in network switches as Zyxel and Cisco.
The Neutron Star 3 is better but about $600 from the company "NewclassD" in Denmark. They arrived today. I ordered 5 of them also for Bluray Player and external SSDs.
I will change the Mornsun to +/-7,5V power supply from two 12V batteries in series with O22 board to 10V down and then the best Sellarz regulators (-132dB) down to 7,5V. The clock gets its own DC20V. The Opamps will be changed to NewclassD Opamps. Regulators come from Sellarz and Belleson.
I need two 8x12 because I need 24 channels.

Do you know where the DSP Chip gets the clocksignal? Or is it internal?
Have you got whatsapp?

Regards
Ralf

Please Log in or Create an account to join the conversation.

C-DSP 8x12 External clock and linear power supply 1 week 2 days ago #55686

  • shegl
  • shegl's Avatar
  • Offline
  • New Member
  • New Member
  • Posts: 9
  • Thank you received: 0
The base clock is in ADSP-21489 all about SPI Interface and Media Local Bus, frequency compared to clocks is set by program which control ADSP, clocks taken by on board XO.
ADSP-21489 cant work as slave MCLK. It can work only as master MCLK and so on.
There is only three problems that ADSP-21489 have:
It's very depends on quality of XO, built-in ASRC suck compared to modern alternatives.
If you want bit perfect you have to reclock input signal with buffer or use ADSP mclk and fs (do software upsampling/downsampling)
End quality very depends on quality of power supply.

Everything above can be fixed without miniDSP team, you can just make FIFO flip flop reclocker from your source with mclk from ADSP-21489. 
Also you can use (replace default XO with better XO with same fc) of internal minidsp and also make a better linear power supply and etc. Yes you will need to do software upsampling to hit programmed fs.
In the end all of this will increase the end quality, but in fact, to measure difference before / after require pretty not cheap (THOUSANDS DOLLARS) precision hardware.
As for me, I'm ok with that C-DSP 8x12 v2 given me.
But I do understand that there is much better chip (with better ASRC ADSP-21564 and so on), there is much better XO, much better opams and much better DAC available on market, there much better power supply. But you getting that you pay for, if you want hifi quality, or "audiophile" version, it's not the place you looking for. For example, if you good in Visualdsp++, and know how it works, you can do a much better with same 21489 cho and cheaper for yourself (You can chose almost any DAC you prefer), but me same as you suck in this (I suppose). So the only option is to ask miniDSP team to make next C-DSP 8x12 with i2s master mode (make pins friendy to share mclk to i2s source) or with better ASRC (ADSP-215* family), HDMI LVDS i2s support,  and better power supply for DACs/Opamp  and DAC level volume control. 

Check ADSP-21489 datasheet on analog devices website, there will be answer on question about clocks.

Please Log in or Create an account to join the conversation.

Last edit: by shegl.

C-DSP 8x12 External clock and linear power supply 1 week 19 hours ago #55692

  • rsqt
  • rsqt's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Posts: 12
  • Thank you received: 0
Hey Alex,

yes, you are right. Digital sources is not mine. I am a loudspeaker developer. Using C-DSP at "home" and in the car has the advantage that you have to modify the same device.
Yesterday the Neutron Star 3 clock from NewClassD in 24,576MHz arrived.
Do you know if I only have to remove the onboard 24,576MHz clock or are there some other parts as caps that have to be removed too?

The Opamps are very small. Do you know some better as the 2068? The "Ultimate OPA" from "NewClassD" is bigger with a small board of 26x23mm so I can only take every second. I'll take them for Supertweeter and Tweeter. But I want to change the other 3 2068 too. I thought of TI L4562. In the mids and lower mids it sounds quite nice (but it is a little bit bigger).

Have a nice weekend.

Regards
Ralf

Please Log in or Create an account to join the conversation.

  • Page:
  • 1
Moderators: devteam