Tandberg Tape recorder model 741B, assembled in august 1964 and still running strong. It is a 3 speed, 4 track stereo with a built-in 2*10 watt tube amp. The only transistors used is in the first amplification stage after the heads. It has 9 tubes: 2 EAM86 (recording indicators), one ECC82/12AU7 (for the erasing head), four ECC83/12AX7 (preamps) and two EL84/6BQ5 (power amp). The amplifiers works independent of each other; For instance, you can listen to one track while you record at the other. The recordings can be played back on the internal speakers (sounds quite well, actually) or external speakers. RCA plugs are used for all connections (including ext. speakers), and includes line in- and output and power amp outputs with a separate center/mono output. It is very sensitive at line voltage and has settings for 110, 125, 145, 200, 220 and 245 volts. If the voltage gets too high (like 235 volts with the selector set to 220) it gets very hot and the sound gets distorted. If the voltage gets too low (10 to 15 volts), the sound looses the "punch".
