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The original amplifier had so called DIN plugs (1958) as inputs, after 1960 they changed to jacks.
Sounds much like an old Fender, just not as sought after. According to some it was based on the same reference amplifier (found in a tube manufacturers handbook) as a Fender that was sold 2 years later.
Specs: Output 40 W (Sinus 32 W) Speaker output (selectable) 100 V (310 ohm), 6 ohm, 15 ohm input sensitivity 5m V - 0.5 V
Was often accompanied by a tape echo called Echolette NG51-S.