Hello,
I am playing around with different old DAC chips for a while. Now I am amused with the performance of the TDA1540 chips (NOS mode, CS8412). I have never heard before so a natural and live like sound. The piano sounds almost like a real one.
However, I see something quite wired that wasn't seen in BB's, AD's and TDA1541. At the DAC output, I see some crosstalk from the LE input. When there is no SPDIF signal the LE has ca. 11,68kHZ so it is audible - constant hiss in speakers. With the SPDIF signal, I see 44.1kHZ or 48kHZ noise - fully synchronous with the LE input. I attach the data from the oscilloscope. The red probe was connected to the analog output. The yellow probe was connected to LE input to the DAC chip.
Do you know the reason why I see such LE crosstalk?
Best regards
I am playing around with different old DAC chips for a while. Now I am amused with the performance of the TDA1540 chips (NOS mode, CS8412). I have never heard before so a natural and live like sound. The piano sounds almost like a real one.
However, I see something quite wired that wasn't seen in BB's, AD's and TDA1541. At the DAC output, I see some crosstalk from the LE input. When there is no SPDIF signal the LE has ca. 11,68kHZ so it is audible - constant hiss in speakers. With the SPDIF signal, I see 44.1kHZ or 48kHZ noise - fully synchronous with the LE input. I attach the data from the oscilloscope. The red probe was connected to the analog output. The yellow probe was connected to LE input to the DAC chip.
Do you know the reason why I see such LE crosstalk?
Best regards
Attachments
That interface is not good for TDA1540 (in my opinion), because TDA1540 needs offset-binary data (first MSB is inverted) and that ebay converter has PCM data. If you wait some time, I will share complet TDA1540 solution (with standard I2S input) in my AD1862 thread (in a few weeks). It will contain my VHDL code for cheap cpld from aliexpress (EPM240T100C5N) or any other CPLD, with detailed manual how to "easily program" that device via USB
That interface is not good for TDA1540 (in my opinion), because TDA1540 needs offset-binary data (first MSB is inverted) and that ebay converter has PCM data. If you wait some time, I will share complet TDA1540 solution (with standard I2S input) in my AD1862 thread (in a few weeks). It will contain my VHDL code for cheap cpld from aliexpress (EPM240T100C5N) or any other CPLD, with detailed manual how to "easily program" that device via USB
Can’t wait to get it. And what about your converter from this thread? Should I try to build it?@drhl No, rather not because that one has not stop-clock. The CPLD based is bit-perfect and tested by me, works great The VHDL code is very simple and lightweight.
I will do tutorial for this CPLD: https://www.aliexpress.com/item/32836059800.html
with this programmer: https://www.aliexpress.com/item/1005002996319656.html
... it is the most cheapest way I found for DIY community ... It probably can't be cheaper, because even if I made some PCBs and sold them cheaply, shipping cost from the EU is crazy. So expensive that you can buy that device from China for the price of EU postage Even with the cheapest CPLD I found the production, the final costs will exceed this device from china 
The VHDL code is very simple and lightweight.I will do tutorial for this CPLD: https://www.aliexpress.com/item/32836059800.html
with this programmer: https://www.aliexpress.com/item/1005002996319656.html
... it is the most cheapest way I found for DIY community
... It probably can't be cheaper, because even if I made some PCBs and sold them cheaply, shipping cost from the EU is crazy. So expensive that you can buy that device from China for the price of EU postage Even with the cheapest CPLD I found the production, the final costs will exceed this device from china Hello.
I also made the spdif-dir9001(pll)-offset binary converter-tda1540 configuration,
There is a similar problem.
When the spdif signal is cut off, there is a lot of noise.
However, even if the play is stopped, there is no noise if there is a spdif signal.
I wish I could solve it in the same way.
Can you describe the solution in a circuit diagram?
I also made the spdif-dir9001(pll)-offset binary converter-tda1540 configuration,
There is a similar problem.
When the spdif signal is cut off, there is a lot of noise.
However, even if the play is stopped, there is no noise if there is a spdif signal.
I wish I could solve it in the same way.
Can you describe the solution in a circuit diagram?