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

Russ,

Very well said. I have enjoyed this DAC, in making a small contribution to its design and then enjoying the process of seeing it become a full-fledged component in my system. Now, I enjoy listening to a very high-end DAC, knowing I built parts of it.

But mostly, I enjoy the music as it comes through the system, with this DAC being a critical part of it. This DAC replaced a Benchmark, DAC-1, Stereophile Recommended Component, because, very simply, it sounded better.

And someday, I might do better than the $10 plastic case. But for now, that does not seem to be affecting the sound.

Keep up the good work.

Craig
 
Russ, if nothing else, I'm happy my post a few pages back seems to have started a mutual love fest. Frankly, I'm surprised you can afford to sell assembled boards at the prices you do. I know that if I tried to sell assembled boards, I would have to charge around $500 to make it worth my time. So, kudos to you and Brian on that. As for DIY, if you're still selling bare boards, then it's ok with me. And hooking up modules, while a little less "hardcore", could certainly still be viewed as DIY, so I'm changing my stance on that.

OTOH, I do think it is fair to ask for a reasonable definition of DIY - that simply prevents commercial manufacturers from getting "free advertising" of their products. After all, we have a forum for that here, too. Let me make clear, I believe TPA operates in good will of the DIY community. I just thought it was time to have the conversation. 🙂 Peace.
 
Brian,

Your assistance in helping me (very new at audio DIY) has been excellent. Your "customer service" for your NFP Co. has also been superb. I thank you.

Keep up the great work. I work full time and barely have enough time to put together my one project.

I don't know how you do it.

Thank you

Darren
 
Brian/Russ,
I'm really looking forward to getting a stock Opus w/ spdif and using that initially, but I have some more ambitious ideas cooking as well.
I see that you have brought all the signals out to use software mode on your board. Have you actually tried setting it up that way? Reading the datasheet, it looks pretty simple - only 4 registers, 2 of which are for volume. Given that I have never done this sort of thing, though, I might easily be overlooking something. (The timing diagram doesn't quite seem to match what the SBC I'm looking at considers SPI, but that is probably fixable.)

My main interest is in being able to configure the slow rolloff filter, and to use the built-in volume control. If you have to reduce gain somewhere, you might as well do it by scaling the filter coeffs. Being able to bypass a preamp entirely might allow direct-coupling to the amp stage assuming you can deal with the offset. Since my amps will be floating on a battery supply, this should work OK.

Anyway - thanks for putting the work into this project. IMHO an inexpensive modular I2S input dac is a very very cool building block - I suspect I'll be ordering several.
 
USB I2S module tested...

And it works just dandy... 🙂

This is what it looks like:
 

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And SMD version of the DAC

Here is the all SMD version of the Opus (well almost all SMD) and it is also tested and works quite well. 🙂

Thanks to Brian for getting these bad boys going so quickly.

We would have the new Wolfson receiver module tested but there was a delay in shipment of a few parts. Hopefully that will be tested early next week.

Cheers!
Russ
 

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Computer to USB module to ...?

I am building a cd player with your parts and a computer cd-rom drive.

I have a PC that is used for the theater. Music and video is played back using SPDIF.

I would like to be able to use the Cd-Player as both cd-player and dac for external device.

I want to use the DAC for the cumputer 2 channel music playback (instead of the Pre/Pro via SPDIF). Since the SPDIF from the PC is going to be used for DVD play, the only other way I can think of is through USB.

Is there a way that I can "share" the DAC for 2 seperate inputs? One SPDIF (cd-rom) and one USB (from computer). Without losing any audio quality for both.

What is the chain for USB? Computer to USB input module to...?

Thank you
Darren
 
Re: Computer to USB module to ...?

DarrenWadsworth said:
I

Is there a way that I can "share" the DAC for 2 seperate inputs? One SPDIF (cd-rom) and one USB (from computer). Without losing any audio quality for both.

What is the chain for USB? Computer to USB input module to...?

We are working on a I2S multiplexer for sharing multiple sources with a single DAC , its not done yet, but for now you could also just use a 4 pole switch.

The chain for USB could just be the USB module(very good but not optimal), or USB -> Opus DAC.

Good luck!

Cheers!
Russ