I am rebuilding a portable audio patch panel that is used to simplify connection of multiple balanced line level distribution amps for broadcast use. In the past I have lost several DAs due to the fact that someone incorrectly patched into a RTS system on the other end of the DT, which carries DC Voltage on pins 2 and 3. Would it be possible to permanently install capacitors in series between the DA outputs and the patch panel to act as DC blocks to prevent voltage from getting to the DA in the case of an incorrect patch? Or would I be sacrificing audio quality as well as frequency response.
Thanks in advance!
Thanks in advance!
Can't see why not...
I'm not familiar with the terms RTS and DT 🙂
And are you trying to block DC from entering an AD convertor or DC from the output of DA convertor ?
The value of the cap depends on the input impedance it works into. I would also add protection in the form of two hi speed (1n4148) diodes to clamp the input to the AD supplies (check the data sheet for the device to see what is the acceptable range of input voltage... if it's below the rails then consider zener clamping).
That stops the possibility of a discharged coupling cap applying a spike of the full voltage to the input as that would still destroy the device.
So the answer is yes... just choose the cap according to the frequency cutoff and impedance, use a high value resistor to ground at the end of the cap to define a ground or reference, and consisder "spike protection" using clamps on any sensitive inputs.
I'm not familiar with the terms RTS and DT 🙂
And are you trying to block DC from entering an AD convertor or DC from the output of DA convertor ?
The value of the cap depends on the input impedance it works into. I would also add protection in the form of two hi speed (1n4148) diodes to clamp the input to the AD supplies (check the data sheet for the device to see what is the acceptable range of input voltage... if it's below the rails then consider zener clamping).
That stops the possibility of a discharged coupling cap applying a spike of the full voltage to the input as that would still destroy the device.
So the answer is yes... just choose the cap according to the frequency cutoff and impedance, use a high value resistor to ground at the end of the cap to define a ground or reference, and consisder "spike protection" using clamps on any sensitive inputs.
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