Tool/software:
I have observed that when i.e. the LEFT DAC is playing a tone, it is coupling to the path of the RIGHT DAC when the RIGHT path is connected (or any other path than DAC L1) to one of the output with an attenuation of -0.5 dB or more, following the attenuation setting. When at 0 dB the tone is not present at the output.
It is like there is an issue with the supply for the attenuator or internal coupling from the DAC line to any other line?
Is there some way to lower this coupling?
Hi Silas,
To make sure I understand, DAC L1 is connected to the LEFT LOP output with gain set to 0dB. When RIGHT LOP is connected to DAC_R1 (I know you said any path so let's pick an example) with the gain set to -0.5dB or lower, you get the coupling of the tone?
How much cross talk are you measuring on the output?
Best regards,
Jeff McPherson
Hi Jeff,
The problem is as shown here, where I can hear/detect the signal from DAC_L1, when the attenuation of R92 is set to -0.5 or lower:
The output level follows the attenuation and the level of the DAC output (though I haven't measured if it follows the steps 1:1).
I measured a relative difference of -43 to -46 dB for Vout (Right_LOP) when R89 is at -0.5 dB and when R89 is muted while R92 is at -0.5 dB.
I suspect the coupling to be within the attenuator some how? Is there anything we could do for the supply to this? I have tried to increased the decoupling capacitance which did not lead to any improvement.
Note: I found a small error in the diagram for R60 and R63, which have been flipped.
