This also completely eliminates one of the most inefficient and non-musical components in a typical tube power amplifier: the Output Transformer. Therefore, the tubes are positioned to naturally and actively respond to the dynamic speaker load. BK Butler's Tube Driver BLUE technology places the triodes exactly where they should be: DC coupled through the output power devices to the speakers. Previous designs generally employed vacuum tubes in impedance-isolated preamp or pre-driver stages. Pics are from Butler website.ĭescription of amplifier design from the Butler website: Numerous reviews available online of the Butler 2, 3 and 5 channel implementations of this unique topography.Īmp is already boxed up and will ship from Chicago as that's where it was sent for reconditioning. It is quite powerful, producing 5 x 150 Watts RMS per channel 8 ohms or 225 Watts RMS per channel 4 ohms. This is the most 'listenable' amp I have ever owned and the sound was not inaccurate, just very well balanced and controlled. Ahead of listing, this amplifier has been inspected internally and externally by an independent audio electrical engineer and bench tested to ensure it meets manufacturing specification. It was my favorite amplifier for many years, but a new set of full size planar speakers drove me to a dedicate two channel setup.

I have had this amp in storage for a few years and decided it was time to let it go. Recently re-conditioned Butler 5 channel hybrid tube amp.

Bk butler tube driver guts