I have an unwieldy system - Alternate Audio 4' planar speakers with ribbon tweeters and 6.5" cone woofer, and a Velodyne subwoofer, tri-amped with an old Electrohome SET (for the ribbons), Conn Push-Pull tube amp for the main planars, and a Nikko Alpha II dual mono SS power amp for the woofers. Preamp is from a Rotel RX-855 receiver. Source is a Thorens TD-160, with Benz-Micro Wood SL (most expensive component of this system!) to a Benz-Micro Lukaschek PP-1 MC phono stage, or a PS Audio Digital Link III DAC.
To this weird but wonderful system, I have just added the El Cheapo FX-Audio Tube-01 tube buffer/preamp (in front of the main Conn PP amp).
Holy Moly! Big improvement in matching the Conn to the planars! Before, the planars would distort with timpani and other low frequencies, when driven very loud. Now there is almost no distortion!
I imagine it has something to do with the tube buffer making the impedance matching much better. Can anyone with more technical knowledge chime in with why there would be such an improvement?
I am very happy with this $40 CAD (including 12V power supply) little gizmo. No noticeable extra noise or hiss, which I was worrying about the most. And the volume knob feels good, and the tubes glow a nice bright red.