DIY Fethead 20dB in line preamp ideas?

Hi guys, does anyone have any ideas/schematics for an in-line phantom powered preamp similar to the Fethead?

I haven't opened up a FEThead, but here's a stab in the dark.

Split the +48v phantom power in to +/-24v with a passive virtual ground circuit or that TI voltage splitter IC thingy.

One opamp for each hot and cold signals with 20dB gain set with precision resistors.

Potential issues:
-non-common-mode noise from opamps
-not enough current from phantom power rails
-gain and impedance matching between opamps

Like I said, this is just off the top of my head but it could be a start.

Another thought: it's only 6dB of gain, but the THAT1606 is a balanced line driver with differential inputs and acceptable input impedance for mics (5k).

However, max supply voltage is +/-20v.

Finlaywatt said:

Hi guys, does anyone have any ideas/schematics for an in-line phantom powered preamp similar to the Fethead?

Click to expand...

Yes. Many compatible plans here: http://www.groupdiy.com/index.php?topic=5743.0

You'll find it's the non-FET version by PRR that has seen lots of real world implementations by now.

See Reply #97 & further.