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

[BobEllis]

Sounds like a shorted diode, cap or regulator. DMM time. You should see a high resistance leg to leg on the regulators.

[fierce_freak]

Good call, Bob. I have two shorted diodes on the smoking resistor side.

[Carl_Huff]

Hmm, shorted or backwards diodes. Sounds like something that I would do!

That's why I always 'stuff & test' power supply components first when building a project. The practice saves 'letting the smoke out of' expensive parts and it's a lot easier to probe around a PCB with a DMM without all those parts in the way.

Carl

[Spartacus]

Can you say the type and package of voltage regulator you use on the DAC? Looking to run the digital supply off 3.3V

Many thanks for your assistance. Dan

[Russ White]

Originally posted by Spartacus
Can you say the type and package of voltage regulator you use on the DAC? Looking to run the digital supply off 3.3V

Many thanks for your assistance. Dan

LP2985 SOT23, but I am wondering why you would want to do that...

Cheers!
Russ

[Spartacus]

Thanks. I'm wanting to try Wolson's new DAC. It needs a 3.3V digital supply.

Dan

[Russ White]

Originally posted by Spartacus
Thanks. I'm wanting to try Wolson's new DAC. It needs a 3.3V digital supply.

Dan

Rgr that.

[dwk123]

Originally posted by Russ White


Brian and I have talked this over several times in the past. We really only have one source that would really benefit (the USB source), so it has not been a high priority for us (lots of stuff going on right now).

Yeah - I figured this was somewhat to 'niche' to have widespread benefit

Still, we have given it some thought and if I were to design a PCB it would probably be around the Analog Devices ADUM2400 Quad-Channel Digital Isolator or something similar.

Thanks for the pointer - I knew AD had a roughly equivalent part, but I didn't know it was a quad. Much better fit since all 4 I2S lines can be handled by the same part keeping skew down. Maybe a bit harder to handle as I'm smd-challenged, but might still be manageable.

There are risks however, but none too major. One would need to be sure that the added propagation delay will not harm anything, it shouldn't as long as the pulses are not badly distorted, which they should also not be.

The propogation delay looks pretty good - unless the incoming I2S signals are already pretty bad I don't think it'll have any problem.

Of course, this brings up the idea of a synchronous reclocker after the isolation, which pushes the entire thing a bit out of my comfort zone. I'll focus on getting sound out of things first, and then look at ways to improve. The ultimate vision of where I think I'm going is pretty complicated, so taking baby steps is probably a good idea to avoid getting lost.

[Vuti]

Does the new Wolfson WM8741 work as a drop-in replacement for the WM8740?
Are there any plans of Opus V1.1 with the WM8741?

[Russ White]

Originally posted by Vuti
Does the new Wolfson WM8741 work as a drop-in replacement for the WM8740?
Are there any plans of Opus V1.1 with the WM8741?

Yes it does.

The only major reason to do a new board would be to more easily support the DSD input option of the WM8741. We may do it at some point. You can actually fully utilize the WM8741 on the current boards. But some of the pin names have changed, but nothing to difficult to figure out.

Cheers!
Russ