High Performance WM8741 Upsampling DAC New Version build thread (show 'n tell too)

[Turbon]

I can compare with what I have but not before tomorrow afternoon or evening.
I got the Apple remote working for two buttons - vol up/down and calmed down the rotary encoder since it was bouncing all over the place.
Now I have to decide what functions to steer with the remote. Brightness and contrast has to go since I'm starting to be short on pins - wish I had a serial LCD...

Obviously TheGimp you have measured no short to GND?

Brgds

[TheGimp]

I removed the 68 ohm series resistor from the output to the input of the 157. Both measure several MEG ohm to ground.

No short.

[TheGimp]

I checked it again this morning at work under the Leica GZ4 (10X) and could find no issues.

[Turbon]

Originally Posted by TheGimp

I've got a signal on BCK_u (PCM2707 Pin 19, FUNC1) of 3.077MHz, but DATA_U (PCM2707 pin 17, DOUT)stays low all the time.

The oscillator looks like it is on frequency.

Pin 5 LRCK_U is clocking at 48KHz.

Does all this sound correct?

It looks to me like DATA_U is wrong and should have the data being clocked by RLCK_U.

I lifted the 75R series resistor and DATA_U is still solid low, at ground potential.

I have frequenses on all these pins... What else have you connected at the time of your test? I have the DIR9001 connected even if I don't use it. I have oversampling set to 96khz for the moment so I have nothing on OSR and I have nothing on FSEL. The rest are as heartwinter communicated.

Brgds

[TheGimp]

I've been reading the data sheets on the parts. In USB mode, with pins 9&16 (FSELs) to the 2707 grounded it is in I2S mode. The DATA_U pin should contain the I2S data.

I've got all the jumpers per the drawing as you do. I've tried both 96KHz and 192KHz.

I have the RX-DA jumper in place as I was trying S/PDIF. It should not matter when the USB cable is plugged in as the 2707 detects USB and pulls HOST active. This drives the MUX to delselect the S/PDIF input and enable the 2707 to drive the I2S input to the 4192.


Irrevalent to the basic problem, I've found a bunch of noise on L2 that is getting into the audio circuit. It is an oscillation of some sort. Not a sine wave. This is with a bench supply that is clean, so it is not PS ripple getting in.

One other thing that bothers me is the 24.576 MHz oscillator is powered by 5V. It drives the converters which are 3.3V devices and specify that the clock may not exceed VDD (3.3V) by more than 0.3V. The 24.576 signal is only going to a bit over 3.3V, and I suspect the crystal oscillator is being overloaded by the signal being clamped by the protection diodes in the inputs to the loads.

[Turbon]

Mine is a Vanguard TCXO 0.3 ppm and it seems to be rated at 5V according to this
Vanguard Ultra precision Golden TCXO, 0.3ppm 24.576MHz | eBay

Couldn't find more decent data with my quick search.

Brgds & good luck.

[TheGimp]

I'm using the same one.

Likewise, I can't find any company called Vanguard. It may be a product line name rather than the company name. Who knows.

[TheGimp]

If anyone has photos of the top and bottom of the DAC PWB without components installed, please post them.

I didn't take any and I need to trace out the board.

TKS.

[MisterRogers]

I have mine at home - I'll snap some and upload this evening.

[tornislv]

I have mine scanned without components @1200dpi, I'll share location for the files via PM, but there is a BUT: is Photoshop *.psd file OK, or do I need to convert to png? Plz PM.