This is a mono valve amplifier with a three channel mixer, made by the Italian manufacturer ‘Geloso’. It was probably made in the early sixties and the output power is higher than 50 Watts.
Apart from having superb audio quality, this kind of amplifiers, they accept all kinds of loads at the output and they forgive mistakes, like short circuits! Any other amplifier without valves would not tolerate short circuits, unless it is equipped with a decent protection circuit at the output!
The company went out of business in 1972, four years after John Geloso death.