DAC AD1862: Almost THT, I2S input, NOS, R-2R

[ra7]

@ra7 Can you check the USB Streamer settings and set the sampling frequency to 44100 kHz and test the sound again?
If no sound, put the scope on pin 3 or 4 and see the scope if there is some data present and alternating while the music plays (you can compare it with the situation when music is paused).

With USBStreamer (controlled from JRiver) confirmed at 44.1 kHz, I setup a test signal of 1 kHz sine wave (same process in the previous post with the scope shots). I see faint traces plus normal traces with the signal on, and then the faint traces go away with signal off. Same behavior on pins 3 and 4.

 

[Markw4]

Here are pics from the scope measurements.

May I ask if the scope horizontal sweep mode is set to auto or normal?

 

[tame]

I intend to build TDA1540. How I2SoverUSB must be configured for this DAC? Will be very grateful for the explanation.

 

[miro1360]

@ra7 So the input logic looks fine and workable You can try one thing before changing the TDA1541A ... try change the capacitor C15
That's all i can think of that could be causing the problem, what else can be wrong (maybe the I/V? --- what is your I/V?)

 

[ra7]

Okay, will look at C15. IV is the one onboard.

Thank you so much!

 

[miro1360]

@tame The configuration is standard I2S: #617

 

[ra7]

Don’t have another C15 on hand. Will order. Should I try the other tda chip in the meantime?

If the DAC chip is working then I should get AC on the 3k3 (R20, R22) right?

 

[tame]

Thank you very much!

 

[miro1360]

@ra7 You can try to pull out both opamps (both, not only one) and insert a passive I/V resistor into opamp socket pins 2-3 (like 330R resistor) and check with oscilloscope if there is any signal on the output

 

[miro1360]

Don’t have another C15 on hand. Will order. Should I try the other tda chip in the meantime?

If the DAC chip is working then I should get AC on the 3k3 (R20, R22) right?

You can safely try (I assume the original TDA is not suspiciously overheating)
AC should be measurable at the output (output connector or opamp pin 6)

 

[Vunce]

Ready for power, hopefully no magic smoke will be let out 😂.
Set up for preamp duty only, no need for relay.

 

[ra7]

@ra7 You can try to pull out both opamps (both, not only one) and insert a passive I/V resistor into opamp socket pins 2-3 (like 330R resistor) and check with oscilloscope if there is any signal on the output

Inserted 470R in both sockets but no signal on pin 2.

Chip is quite warm to touch.

 

[ra7]

Tried another chip, same result. So, it is not the DAC, output, or input chips. C15 is next but a few days away.

 

[NIXIE62]

PCM1702 board.

 

[Vunce]

Fast work Nixie, Nice!!

Ra,
Hope you get your TDA1541A board straightened out and working 🙏

 

[ra7]

Vunce, my brother, your good wishes did the trick! Perhaps I was too shy about pressing down the dac chip. On the second one, I noticed or thought some pins are not making contact. So I twisted and bent them and voila! Sound!!!

Those pins are tricky. Miro, thanks for your help and sorry for the trouble!

 

[Vunce]

Yahoooo!!!!
Yes, the chips push in easily, but to seat them into the sockets a bit of thumb pressure is needed to bottom them out.

Enjoy Ra!!

 

[miro1360]

@ra7 Sometimes you need to "push more" to get the result

@Vunce Nice build as always, I'm curious what you say about it

@NIXIE62 That was fast, very nice

 

[zoom777]

Put into your collection also a pair of DAC702BH, you will never know when I bring it to the life
(it must be DAC702xx, where xx can be KH, BH, LH, CH, SH), CH and LH are the most precious (almost not available), KH is the least precious, BH with SH are in the middle (SH for wider temperature range, almost not available)
AD1862 awaits the fight

I am contemplating to get the Dac702ch if you are certain about bringing to life... Not sure if they are genuine... Supplier claims them to be unused.

Put into your collection also a pair of DAC702BH, you will never know when I bring it to the life
(it must be DAC702xx, where xx can be KH, BH, LH, CH, SH), CH and LH are the most precious (almost not available), KH is the least precious, BH with SH are in the middle (SH for wider temperature range, almost not available)
AD1862 awaits the fight

I am very tempted to pull the trigger on a pair of dac702ch. Supplier claimed to be new chips. Not sure if they are legit. Pic is the actual chips they are supplying. They look beautiful. I only have 7 days to return if I want to. , 😁

 

[Brijac]

It is a risk If you buy it before the dac pcb is made, then you must be prepared that chips may not be working and you can't return.