Here is a Stereo Tube Preamplifier Kit that is easy to build, and is just fun!  The Tube Preamplifier utilizes a 5670 triode.  The Preamplifier is compatible with all "L" Series Amplifiers, it gets its B+ and filament voltage from the Amplifier board and can provide 10 to 30 db of gain.

The PL Stereo Tube Preamplifier comes in kit form (K-PL).  The kit comes complete with all the resistors, capacitors, tube, circuit board, and necessary hardware for mounting on a "bread board" provided (which is compatible with the amp you purchase or have previously purchased).

NOTE:  The Preamplifier and Tone Control kits cannot be used together as they both have gain.

Model PL Stereo Tube Preamplifier

Model PL
   Page Updated August 2015

   Input Impedance = 100k ohms
   Frequency Response = 20 to 20,000 Hz
   Signal Input =  From Jumpers to Amplifier PC Board
   Gain = 10 to 30 db - set by a resistor
   Two channel  

CautionThese amplifiers may be operated as supplied, however voltages in excess of 240 volts are present on the board and the tubes get very hot. It is advised that the amplifier be mounted in a well-ventilated metal enclosure to reduce the potential of  fire or shock.
"L" Series
16 Watt Stereo Amp with Preamp
   If ordering separately specify which kit you already have, so we
   can furnish the correct mounting board.