Pro Audio Design Forum

i also have to reset almost every time i turn the evm on ( a fair amount of noise can be seen on the channels) i am using a toroidals and regulated pcbs I was considering to have a relay come on maybe 1 sec after the main power switch is turned on to do this for me, or, as this is for me only, a lit...

Hi thank you for you reply. I have had some success with the circuit attached. inserted between the preamp and the EVM. I had to use 47uf caps on the input of the EVM. (very little dc now. I have to zoom right in to see the dc, using a dc offset plugin is still beneficial after a recording. I have y...

hi I notice c64 (unpopulated) has a nice large pad, just happens to connect to Vocm! and the 2.7nf that I think you mention is ' c61 ' right up close to the PCM4222 so that is out of the way and post any potential modification. I could scratch the traces (if the traces are only on the top layer) aft...

Hi thanks i will have my preamp inside the same box as the EVM. The preamp is taken out of an old mixing desk channel. So i am simply using its unbalanced insert output to go into the evm. it would be nice to route this preamp into the EVM with as few components as possible to keep it low noise. I n...

Thank you

I shall try a few tests with some through hole caps.

All the best

additional to above. I just noticed you mention the polarity issue. I shall try around 150uf with a 100k resistor soldered to ground too. " If AC-coupling capacitors are installed do note that the the polarity markings on the schematic and the layout are incorrect. They should be at least 47 µF...

hi thank you. I had noticed placing a 100uf electrolytic in series before the EVM , almost all the DC went away. I wonder, what value of cap would you recommend? would 150uf 25v be safe? it seems the resistors r1 r2 r6 r5 will need to be removed when installing the capacitors. I am sure your very bu...

HI I managed to get the PCM4222evm working, I had some DC offset issues only if the EVM high pass filter was not turned on. test 1 computer> RME balanced >> EVM AES >> RME AES/computer = No problem. ( even with the EVM HPF switched off) very low noise test 2 (same as before but insert an external so...

TI have informed me that the EVM was never meant to be chassis mounted. Although the pdf seemed to indicate one could have a shielded and secure environment to test. " The PCM4222EVM provides a complete environment for evaluating the functionality and performance of the PCM4222 integrated circu...

thanks for your reply. yes good idea, although i am right out of space in the box. i would need to reshuffle some parts. I hoped it would just slot in as the PDF states "chassis mounted for AES j7 j9" i am in communication with TI so hopefully they will email something interesting. i shall...