Focusrite Scarlett phantom power questions

Has anyone measured the phantom voltage and current output of the Focusrite Scarlett 2i2 (2nd Gen) USB Audio Interface?

I have only found this from searches reply #9https://www.gearslutz.com/board/low-end-theory/778381-focusrite-scarlett-2i2-cad-m179-performance.html 9.5ma for one channel 19ma for both or 9.5ma total for both channels?
I don't want to buy it, test it and then return it. 
Found this https://us.focusrite.com/usb-audio-interfaces/scarlett-2i2/specifications
But does it measure 48VDC? Does it supply 10ma per channel? The 48V is on the front panel section but not in the more detailed list below it.

It would be nice to know the real voltage and max current for each channel and all channels on.

The older microphones like the early u87 , KM8x  need 48VD to work the best.  Other microphones can use some current.

I am looking at this because it is reported to run in linux.

Gus, I sincerely do not recommend any of their bus-powered models. The 18i8 was passable and I made an entire album on it using almost a single microphone (MK4), but the bus powered models have all sorts of performance issues before worrying about any of the phantom powering, and the drivers are sketchy on all the Focusrite models. The newer series is probably the best sound performance in that price range, but I don't believe they fixed the reason I ditched mine (which is that they have lousy handling of a lot of external gear ... pretty bad noise performance on the line ins).

That said, I didn't find anything wrong with the phantom power on the 18i8 and they don't fudge their numbers with their other specs so I'm pretty sure if they give you a fairly precise 9.8mA you can trust that.

I have a 2i2 and it works very well. The only thing you have to remember with USB powered devices is to make sure your PC can supply the required current. The 2i2 really needs a true USB 3.0 interface that can really supply the specified 500mA. It works perfectly under Linux - no drivers required.

The international spec for phantom power voltage is 44V to 52V. Anything in that range meets the spec. There is 3.4K of resistance in series with this supply so if you pull 9.5mA out if it the voltage will drop by 32 volts so it could be as low as 12V legally. Most microphones pull 2 to 3mA at most from a phantom supply so even if the total is only 9.5mA is should be plenty. Note that 3mA phantom current could drop the voltage by 10V.

Cheers

ian

thanks for the replies

a good link for a fast test http://shure.custhelp.com/app/answers/detail/a_id/3789/~/how-to-test-phantom-power-voltage-and-current

I was looking for something compact that works with a laptop running Linux.  This model is one that is reported to work with linux. Ian thanks for the confirmation

I was also thinking about using the 2i2 as part of a test system for microphones this is why the phantom supply is important.  I was even going to match phantom resistors if needed to replace the ones inside the 2i2 if they are not matched well enough for what I want to do.

Gus said:

thanks for the replies

a good link for a fast test http://shure.custhelp.com/app/answers/detail/a_id/3789/~/how-to-test-phantom-power-voltage-and-current

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The voltage test is OK but the current test effectively shorts each 6.8K resistor to ground in turn. There is nothing in the spec that I am aware of that says a phantom circuit should pass this test. Having said that it is very unlikely that any phantom supply will not be able to survive a single short.

I was looking for something compact that works with a laptop running Linux.  This model is one that is reported to work with linux. Ian thanks for the confirmation

Click to expand...

I use REW which is a Java program that runs on windows and Linux. I running on a fairly old laptop, a Samsung R700,  which dual boots into Vista or Linux Mint. REW runs fine on both OSs. I only use windows when I use the Lindos test set because  it does not have a cross platform app.

The R700 has 4 x USB 2.0 ports. Two are on a double connector block and the others are separate. The 2i2 will only work on one of the separate connector ports - I seem to remember it draws the full allowed 500mA.

Cheers

Ian

Does Lindos run in wine.

bought the newer version 2i2
measured 47.5VDC on one channel with a sterling ST51 microphone in the other channel
I need to match some resistors to test the current.
I am amazed what you can buy for under $200

midwayfair thanks for the information I decided to buy it because it works in linux. 

If you search for audio interfaces that work well with Linux is one reason I bought it

Gus said:

Does Lindos run in wine.

Click to expand...

I have not been able to get it to do so.

Cheers

Ian

RME babyface runs on linux as well in class compliant mode. works fine