PhAnTom PoWer -clicking on other channels

Has anyone ever had problems with a click/pop sound sound when the phantom power is engaged on a neighboring channel? It's very low in level and I hear it more when the channel's gain is 3/4 on API-312 type preamps.

I am using my Relay PCBs in this setup. The phantom is not actuated by a relay but by a switch on the front channel. The circuit is your basic 240 Ohm resistor to a 220uf/100V Coupling cap and 6.81K resistors. The grounding seems like an adequate star ground setup.


Has anyone had this problem with my PCBs? If so, hopefully I can find a workaround to what I did wrong.

excuse the bump (no not that kind...) :wink:

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Are the inputs to the clicking channels loaded or open circuit?

Try: (depending on implementation)

Series resistance with the switch, to limit current inrush with capacitor charge...

Parallel R/C to reduce switchoff click also.

Making sure that you don't have a modulated ground. This will often crosstalk as much as anything else.

Keith

[quote author="SSLtech"]Try: (depending on implementation)

Series resistance with the switch, to limit current inrush with capacitor charge...

Parallel R/C to reduce switchoff click also.

Making sure that you don't have a modulated ground. This will often crosstalk as much as anything else.

Keith[/quote]


1. The Pahntom has a 470R series resistor -is that what u meant?

2. I think you are talking about a bleeder R by phantom cap to ground, right?

3. I am not sure what a modulated ground is, can u elaborate.

emtee-I think it was open, on channels. On one test I did have a dynamic mic on the non-phantom channel of course.

Thanks so much for the pointers

-Here is the switch schem that goes to relays and phantom. Could the grounded resistor and LED do anything strange?

I'd start by putting a scope (in AC-only mode) on the phantom supply, to see how much of an effect a switch causes on the supply. Maybe beef that up a bit with filtering?

Or maybe it's the physical location of the relays - radiated from the coil into the circuitry?