[CSO]

Well, since the Opus Dac boards are out of stock, I decided to get an Opus USB receiver module and mess around with it a bit. The Opus USB receiver board uses the TI PCM2707 chip which not only provides S/PDIF output or I^2S output, but it also has analog L/R outputs. Russ has very nicely put a four terminal header on the board to connect to headphones, etc. The single Opus USB receiver board can be used as a low-mid quality dac on its own, which is nice for an office computer based stereo. It is totally powered from the USB 5V bus and installs in Vista without any extra drivers (XP too I believe). Although described "low-mid" fi, the analog outs from the Opus USB module sound good in my office.

A caveat to the PCM 2707 chip is that the function select (FSEL) seems to allow for analog audio output only in the S/PDIF mode, so you can only get analog out from the Opus USB board when it is jumpered to S/PDIF. It took me a while to figure this out.

I am curious to know if anyone has used the serial programming interface (SPI) on this chip for anything. Russ has given us a header for this as well.

 

[BrianDonegan]

Quote:

A caveat to the PCM 2707 chip is that the function select (FSEL) seems to allow for analog audio output only in the S/PDIF mode, so you can only get analog out from the Opus USB board when it is jumpered to S/PDIF. It took me a while to figure this out.

The new version of these board have a DIN pin next to the digital output header. If you pumper DOUT to DIN, you can use the analog outs in I2S mode as well.

 

[CSO]

Quote:

Originally Posted by BrianDonegan /img/forum/go_quote.gif The new version of these board has a DIN pin next to the digital output header. If you jumper DOUT to DIN, you can use the analog outs in I2S mode as well.

Cool. I wondered what the DIN was for. Now I know. Nice design. Thank you.

 

[SoapSeller]

Small question, for the Opus output caps, 6.3V rating is enough?

 

[naamanf]

Yes. I tried it with 6.3V 47uf BGs with no problem.

 

[SoapSeller]

Thanks.

I'll report back after I'll change the caps(going to try BG as you did...).

 

[rodentmacbeastie]

Brian,

Just out of interest, why didn't you use the DSD1794A in your COD instead of the PCM1974A? I like the idea of a current output DAC but I will be using your DSD support on the Opus. The DSD and PCM DAC chips are both 28 pins but I don't think they are interchangeable.

 

[Russ White]

I designed the COD around the PCM1794A because our sources are all PCM for now.

We will try out DSD with the WM8741(which is cool because it does both PCM and DSD very easily in hardware mode) and perhaps I will try the DSD TI parts at some point. The biggest obstacle to most people using DSD parts is just getting to unencrypted DSD. So demand is not very great.

Cheers!
Russ

 

[Nebby]

Just need to find a player that has somewhat accessible unencrypted DSD signal points

 

[rodentmacbeastie]

Quote:

Originally Posted by Nebby /img/forum/go_quote.gif Just need to find a player that has somewhat accessible unencrypted DSD signal points

That is the ticket. I will test this out with the Opus when I can get a DAC and a doner player.

 

[BrianDonegan]

Quote:

I will test this out with the Opus when I can get a DAC and a doner player.

...and when we can get WM8741s! We have been working with two Wolfson distributors, and even Wolfson directly. We can't even get a date as to when we can get them. Expecting a reply from our Wolfson rep soon...

 

[Nebby]

I've found out that the Oppo 981 has I2S headers that are wide open, so I think I will pick up one of those and hook up a spdif board to that and call it good enough

Though I need to read up and find out if it's possible to output both a coax and toslink spdif out at the same time, so I might be able to do some comparison listening

 

[MASantos]

Hey Brian, is the otto promo only valid if you buy the receiver modules outside the combo?

 

[Nebby]

Also, do we need to add the otto in cart for the promo, or will it automagically be put into our shipping box?

Btw, great new pictures!

 

[BrianDonegan]

Quote:

Hey Brian, is the otto promo only valid if you buy the receiver modules outside the combo?

Combos count. I will make it more clear on the page.

Quote:

Also, do we need to add the otto in cart for the promo, or will it automagically be put into our shipping box?

I will add it. If you accidentally buy it, I will refund the cost.