Top-view of a Leben CS-600 tube amplifier with its lid removed showing:

1) Four transformers - adding considerably to the units weight of more than 22 kilos

2) Four EL34 / 5881 output tubes. As of now, they're EL34 from the German producer RFT.

3) Four 6CS7 driver/preamp tubes. As of now, the'yre from Marconi & General Electric.

The Leben CS-600, which is hand-assembled in Japan, is amongst the best tube amplifiers in its price class.