I own the F3 and F5.
Both are terrific products with the F3 being a bit more sophisticated and refined. However, it is a relatively low output amplifier. Furthermore, the user must be cognizant of the low input impedance (10K) so many tube preamps will not work well.
The F5's higher power output and higher input impedance make it more friendly for use with a variety of speakers and preamplifiers. It will also drive a 2 ohm load without blinking.
I am a Pass dealer but have no financial interest in First Watt products.
Both are terrific products with the F3 being a bit more sophisticated and refined. However, it is a relatively low output amplifier. Furthermore, the user must be cognizant of the low input impedance (10K) so many tube preamps will not work well.
The F5's higher power output and higher input impedance make it more friendly for use with a variety of speakers and preamplifiers. It will also drive a 2 ohm load without blinking.
I am a Pass dealer but have no financial interest in First Watt products.