Could I change a bit on an ADC chip from low to high with a CH341a programmer?
Pin 19 of AK5385 is can be held at ground (L), or else at Vdd (H). It recommended to change it only when PDN = L (page 16 of the datasheet). If one wanted to be able to switch it at some arbitrary time, it could be pulled up to Vdd with, say, maybe a 10k resistor. That would make it H by default. Then a switch or transistor could be used to pull pin 19 down to ground in order to set it to L.
Since pin 19 has no memory capability of its own, an EPROM programmer should not be needed.
Since pin 19 has no memory capability of its own, an EPROM programmer should not be needed.
Thank you Mark. I ended up jumping Pin 19 to pin 16. And it seems to have engaged the HPF as im getting a smaller DC offset. There is still .003% DC offset found. I wander if the crystal oscillators are bad...
Attachments
I know it sounds silly, and it's because im very new to this type of thing. Do you think so? Or maybe bad capacitor values?
Hi Mark, in Logic Pro there is a "Remove DC Offset" that detects and removes the offset in a given audio clip. The issue is, with a session thats full of audio clips, it can be a hassle. Even though .003% is small, I can still hear a click at the beginning and end of an audio clip where the DC offset is off center and creates a click.
Im not 100% sure, but im 99.9% sure, because when I use the remove DC offset, it detects .003% and removes the offset, and the clicks are gone. Also only happens with digital signal, the analog outs side of the mic preamp are perfect 0.000% dc offset detected. so it has to do with the digital side of the mic preamp. The picture I posted is it. Maybe the load capacitors on the crystals are wrong?
Hi Mark, yeah its an ADC. Im not sure, but that's a good question. How would I check? Multimeter?
Hi Mark, I just checked with a cheap o-scope and a DMM, and not really any DC offset...+4mV movement.
Seems like it would probably be wise at this point to take a closer look at wav files that include pops and the beginning and or end. The thing is to stretch out the waveform magnification at the beginning an end of the file to see what the sample point amplitudes look like. Does it look like a DC offset problem, or does it look more like a failure to fade in/out the starting and ending tails of the track?
For example, if a track starts at the peak of a sine wave then there is a sudden change from zero volume to some higher volume at the first sample. That will cause a pop. Digital audio files have to start at digital zero volume level, then quickly yet smoothly fade up to normal volume. That fading is normally done automatically in the recording software if using default settings.
To look at individual sample points I have used the audio editor, Reaper. Likely that Audacity could work too. However, in the case or Reaper I know it will by default insert short fades at the beginning and end of an imported wav file to prevent accidental pops. Also, know how to remove those fades to look at the actual data points in the file. Not sure how that works in Audacity.
For example, if a track starts at the peak of a sine wave then there is a sudden change from zero volume to some higher volume at the first sample. That will cause a pop. Digital audio files have to start at digital zero volume level, then quickly yet smoothly fade up to normal volume. That fading is normally done automatically in the recording software if using default settings.
To look at individual sample points I have used the audio editor, Reaper. Likely that Audacity could work too. However, in the case or Reaper I know it will by default insert short fades at the beginning and end of an imported wav file to prevent accidental pops. Also, know how to remove those fades to look at the actual data points in the file. Not sure how that works in Audacity.