help in identifying phono preamp- solid state, 1980's? possibly european - Dual ?

I got the attached phono preamp when I bought a Technics SL1100 recently. Apparently the previous owner had installed it in the cavity underneath the tonearm . In any event , interesting unit - DIN plugs in and out; looks like polystyrene caps - mostly German brands from what I can tell. Only possible clue is a "Dual" sticker on the side of the case . Switchable between 110/220v. Previous owner not available - thus my request. Any info appreciated . Thanks
 

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