• Disclaimer: This Vendor's Forum is a paid-for commercial area. Unlike the rest of diyAudio, the Vendor has complete control of what may or may not be posted in this forum. If you wish to discuss technical matters outside the bounds of what is permitted by the Vendor, please use the non-commercial areas of diyAudio to do so.

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

Jump to Latest
#803
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
 
#808
Russ White said:


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).
Click to expand...

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.
Click to expand...

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.
Click to expand...

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.
 
#810
Vuti said:
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? 😉
Click to expand...


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
 
#817
Man, looking at the pics makes me not so proud of my work. Maybe it's just the second pass of soldering I did after trying to troubleshoot.

I'm not sure what the black goop is. I noticed that diode actually smokes when the board is on as well, so it's possibly something that is burned. I want to say that the heatsink did get hot, but I'll have to turn it on again to confirm.

I don't have a meter that tests for capacitance. The resistors actually read 10 ohms, and checking the kit contents on the LCPS page indicates 20 ohm resistors. Is that alright?
 
#818
Yes, 10R is fine (new value).

Referencing the schematic: http://www.twistedpearaudio.com/images/lcps/lcps_schematic.png

If D1 is smoking, and R1 and R2 are smoking, yet the VReg output seemed correct (voltage anyway), my guess would be a bad cap (C2 or C3) or a problem with the inductor resulting in a short. Another possible problem would be how your trafo secondaries are connected. If it's an Avel, the leads should go Black-Red-Orange-Yellow.

If you want to send me the supply, I can take a look and make it right.
 
#820
Will we see the WM8741 in the next round of boards?

WM8741 flyer

WM8741 datasheet


A little question, did you notice the sound of the WM8740 changes with
the temperature of the chip???
Heating it up causes the soundstage to blurry,
cool it down and everything comes into place again?
Double-checked all voltages, no change there (with temperature).
The receiver also stays a consistent performer, no matter what temperature.
 
You must log in or register to reply here.
Top Bottom