Considering a First Watt F-4

You'll need about +/-20Vpk drive, or 14Vrms to get full power.

http://www.firstwatt.com/pdf/prod_f4_man.pdf

Francis

You're not getting deluged with replies, so I thought I'd chime in.

I also own a J2, in my case driving my horns. It's everything Photonman said. If you buy from Mark at Reno Hi-Fi (as I did), as far as I understand things they will let you try out the F4 for a certain period, and return it if you're unhappy.

I wanted to make sure you understood that the F4 is a buffer, and has no voltage gain, so it requires a fairly hefty voltage drive to reach full power.

Francis

David,

I suspect you ran into the difficulty I mentioned, that the F4 requires a very large voltage drive to achieve full power. This is a separate issue from gain. Some preamps are capable of outputting the voltage necessary; some aren't.