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Mr White's "Opus", designing a simple balanced DAC

can i presume that 1 single avel lindberg transformer and 1 LCDPS can supply power to 2 Toslink unit, 1 sp/dif receiver, 1 darwin, 2 Opus DAC board without any problem? In this configuration - is there any easy way for the Darwin to get its 5v supply?

The transformer and power supply definitely have enough current capability to power all of these.

In order to keep one side of the supply set to 5V for Darwin, the easiest thing to do would be to power all of the 3.3V items from 5V along with the Darwin. This will provide enough voltage for the onboard 3.3V regulators. The 5V items can then be powered by 7+V from the other side.

The 3.3V items in your list are the Torx, S/PDIF receiver and possibly the digital section of the DAC*.

The DAC analog section is 5V.


* Up until now, I have been using 5V vregs for the digital section for capatibility with 5V I2S sources. The new Opus boards (v2.0) will use a 3.3V regulator for the digital section.
 
Sdif2-3

One possibility is to take the SDIF DSD signal going to the on board DAC of a player, and run it through a digital interface chip (buffer it) then out to 75ohm BNCs.

This would require adding 3 BNCs to the modded DAC (LD RD, C64). Then you could have a similar solution on the receiving end. This would allow you to use an external DAC, and not have to embed the DAC in the player.

The more I think about it, the more I like this idea, but you would still need to find and tap the raw decoded DSD.

The nice thing about the Wm8741 is it supports both bi-phase and uni-phase DSD encoding.

Anyway I am looking at it, and will keep you folks posted.

Cheers!
Russ
 
Re: DSD Output

audionutty said:
Would you have to hook up separate outputs for DSD versus say 24/96 LPCM (coming from decoded DVD-Audio, or Dolby True HD/Dolby Digital Plus)?


Well those would probably be better served with SPDIF output.

In short I don't have a good answer without looking at the specific application. Also you would have to be sure the DAC can accept the LPCM.
 
BrianDonegan said:

* Up until now, I have been using 5V vregs for the digital section for capatibility with 5V I2S sources. The new Opus boards (v2.0) will use a 3.3V regulator for the digital section.

Can we change the regulator ourselves (type?)?
Or did you change more than the chip. (both receiver and metronome are already at 3.3V, so I'd like to save some mA's and switch from 5 to 3.3V on the DAC's digital side)
 
Can we change the regulator ourselves (type?)?
Or did you change more than the chip. (both receiver and metronome are already at 3.3V, so I'd like to save some mA's and switch from 5 to 3.3V on the DAC's digital side)

Well, the change to 3.3V was for WM8741 support, but I just heard from Wolfson that samples have been delayed for another 2-3 months, let alone production quantities, so we will be selling WM8740s for a while yet. I can therefore continue to use 5V vregs for the Opus digital section.
 
Russ White said:

also many 5V parts don't work as well at 3.3V even if they "can" be used at that voltage. So I don't think I would change it.

Wolfson marks 2.7-3.6V DVDD on their WM8740EV1M evaluation board manual. (page 9 of the manual) And 5V AVDD
But they print 3-5.5V on both connectors DVDD and AVDD.
:cannotbe:
While on the same board, they use 5V for the CS8427.

Your are right, it's a lot of work to change and win 33% power consumption (heat) on the digital side of the DAC.
I still don't know if it's a 5V part capable of working on 3.3V
or a 3.3V part, capable of working at 5V.
(one thing is sure DVDD should be <= than AVDD)
 
Re: Re: DSD Output

Russ White said:



Well those would probably be better served with SPDIF output.

In short I don't have a good answer without looking at the specific application. Also you would have to be sure the DAC can accept the LPCM.


I should clarify what I was looking for a solution on: 24/192 digital output non-downrezzed feed from a Blu-Ray or DVD player

Maybe I don't understand but I assume that after dolby digital is decoded, it exists as a bunch of I2S channels going to the DAC, the HDMI chip and the SPDIF chip (If they are external and not integrated into the decoder). So I assume that I would need to tap all those I2S channels and run them into the DAC box if that is possible.

The decoder's built-in SPDIF outputs, and the output of any SPDIF chips on probably all players are down-rezzed to 16bit/48KHz because SPDIF does not have content protection.

So I was just looking for a way to get the full 24/192Khz signal out of the box digitally without it being down-rezzed.

HDMI is out because of HDCP, so it seemed that an inside the box mod to tap the signal before the HDMI chip was the only solution.
 
DEM-DIR9001EVM Evaluation Module

Since the S/pdif board for the Opus is backordered, does this seem to be an suitable replacement?

thanks ...


http://focus.ti.com/docs/toolsw/folders/print/dem-dir9001evm.html

Product Information
Back to TopDescription

The DEM-DIR9001 is an evaluation board for the low jitter, Digital Audio Interface Receiver DIR9001. It isoperated by either a single +3.3 V power supply, or a +5 V power supply.

The DEM-DIR9001 has both an Optical Toslink input and a Coaxial input for the SPDIF interface which can achieve standard digital audio interface format IEC60958, AES/EBU, and JEIAT CPR-1205 (formerEIAJ CP-1201, 340).

The DEM-DIR9001 recovers standard system clock and PCM audio interface clock from incoming biphasesignals such as SPDIF, IEC60958, and AES/EBU. These signals are provided to the audio DAC/DSP, buffer output, and direct output.


Back to TopFeatures

* One-Chip Digital Audio Interface Receiver (DIR) Including Low-Jitter Clock-Recovery
* Compliant With Digital Audio Interface Standards: IEC60958 (former IEC958), JEITA CPR-1205 (former EIAJ CP-1201, CP-340), AES3, EBU tech3250
* Clock Recovery and Data Decode From Biphase Input Signal, Generally Called S/PDIF,EIAJ CP-1201, IEC60958, AES/EBU
* Biphase Input Signal Sampling Frequency (fS)
* Range: 28 kHz to 108 kHz
* Low-Jitter Recovered System Clock: 50 ps
* Jitter Tolerance Compliant With IEC60958-3
* Selectable Recovered System Clock: 128 fS, 256 fS, 384 fS, 512 fS
* Serial Audio Data Output Formats: 24-Bit I²S;
* MSB-First, 24-Bit Left-Justified; MSB-First 16-, 24-Bit Right-Justified which User Data, Channel-Status Data Outputs Synchronized With Decoded Serial Audio Data
 
hershann said:
Russ,

other than DSD support, does the 8741 offer any other advantage over the 8740?

her shann


The parts are very similar. There is a different filtering scheme for the 8741, which is new, and sure be at least somewhat better, especially at higher sampling rates. There will be very little difference for 44/16 material.

The biggest issue is you can actually get the 8740 right now. The 8741 will not be in reasonable supply for a few months at best. We have not even gotten our samples yet.

So until there is some availability we will be using the 8740 which is proven and no slacker. :)

Cheers!
Russ