By switching two selectors inside of the cabinet, you can use either of 6L6GC or 6CA7 (EL34) and LED indicators on the front panel will show you which tube is applied.
"PREAMP-IN" terminals on the rear panel allow you to use CS-600 as a power amplifier.
By switching a selector on the front panel, by-pass all the functions only excepting a Volume control.

Features:
-Twin-triode tube 6CS7 for the first-stage amplification.
-WBT type speaker terminals.
-Heavy-duty output transformer for 50W grade amplifiers.
-Large capacity choke-coil: 5H350mA
-Dumper tube 6CJ3 (for Colour TV use) is applied to delay a supply of high voltage (B-Voltage) to output tubes in order to protect output tubes from damages and to longer the life.
-All high-end audio grade electrical components (condensors, resistors)
-Operation lamp indicator
-Succeeding a front design of CS-300/CS-300X.
-24K Gold-Plated Knobs.
-Side Wood-Panels.

Functions:
-Power Amp Direct Switch. (All functions by-pass only excepting Volume control)
-Muting Switch.
-Stereo/Reverse Switch.
-Variable Output Impedance: 4/6/8/16 Ohms.
-Tape Monitor Switch.
-Bass Boost Switch.
-Headphone Output.
-Speaker/Headphone Selector Switch.
-Tube Indicator Lamps.