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API 500V phantom power question 500 Series Chassis
Old 13th June 2015
Gear Maniac

API 500V phantom power question

I had a similar thread in "So much gear", but figured I'd get more traction here.

So I just switched my 500 series chassis from a Radial Powerhouse to an API 500v. On the Radial, phantom power was always on; with the API, there's a separate switch for phantom on the power supply.

With the Radial, if I turned phantom power off on the preamp, I could then plug and unplug (solid state) mics without any loud thump, even with the gain up.

However, with the API, even if I turn phantom off on both the preamp and the PSU, I get a loud thump when plugging in a mic. The only way around this to turn the gain all the way down on the preamp. The "pop" is volume dependent; i.e. the louder the output gain on the preamp, the louder the "pop".

Is this normal? In my experience, as long as there's no phantom power, I shouldn't be getting any signal from a solid state condenser.
Old 13th June 2015
Deleted 86c3d96
That's one funky phantom power question.
Old 13th June 2015
Gear Maniac

Originally Posted by Deleted 86c3d96 View Post
That's one funky phantom power question.
Glad you enjoyed it.

To summarize: why is there still a thump when I plug my mic in, even with phantom power off?
Old 13th June 2015
Gear Maniac

Old 13th June 2015
Lives for gear

You would have to supply the schematics for both racks and the preamp module you are using to truly answer this question.
It is possible (as a guess) that one rack (that thumps) has a 'default phantom supply' which is taken from the 16 Volts unless 48 is present. This would mean it never actually goes 'off' in the rack but depends on a switch on the module.
Matt S
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