I have been using these with SET amps, like 2a3 or 300b output tube based amps, with great results. In a small room, the realism can be stunning, especially with female vocals and small ensemble music, jazz or chamber.
From FrtizSpeakers website:
Frequency Response: <45Hz to 22kHz
Design: Single driver, front or rear ported bass reflex
Driver: 6 inch Fostex FE 167E Banana plant fiber cone
Sensitivity: 94 dB
Nominal Impedance: 8 ohms
Recommended Power: 5-60 Watts RMS
Dimensions: 18H x 8W x 11.5D
Weight: 22 lbs. each
They are shielded so they can be used near tv, computer & audio
equipment. These work and sound great with low powered tube amps-
Push-Pull & Single-Ended Triodes, Gainclone & Tripath amps such as the
Trends, Little Dot & Sonic Impact T-amps. They also work equally well
with higher powered & older vintage Stereo & modern Surround Sound Home
Theater amps & receivers, just be careful not to play them too loud!
The drivers are wired up and Silver soldered with Canare wire. The
terminal connectors are all brass gold plated binding posts and will
accept spades, banana plugs or 4 AWG wire.