Tesla Studioecho A Tape Echo Machine

A tape echo machine built around 1982 in Czeckoslovakia, in the days of the cold war. I am sure this machine is not very common, and could even be a rarity. It is similar to other tape echo machines of the day. It has many similarities to the german made Dynacord echo machines, and it seems likely that the Tesla factory modelled this machine after Dynacord.
Features are:

Three play heads, one record head and one delete head
Original sound pass-through knob
Record level knob
Record level meter
Hall knob, to control feedback level for the three push-button setting
Three push-buttons, one for each play head
Zap echo knob for long echo
Zap echo feedback knob
Echo Bass EQ knob
Echo Treble EQ knob
Echo level knob
Button to disconnect tape drive

There are trim pots on the inside of the machine to adjust bias, which is nice if you change tape type. The machine seems to have fixed tape speed, so only the push-buttons can be used to select delay time. But once adjusted correctly the echo sound is really nice, and ample feedback on a combination of all three tape heads can produce a rich and complex long tail of sound. The chassis is entirely made of metal, and is very rugged. The tape mechanism supports both an endless tape loop and a tape cassette. Finding the matching cassette will probably prove impossible, but tape loops can be made from standard 1/4" tape.