The original KLEIN & HUMMEL UE-100® EQs are extremely rare and expensive. But Rafa Sardina – who has 12 Grammy wins and 35 nominations – owns 10 of them!
What is so special about this weird and wonderful device

For some time, hardware equalizers had to each be developed with a specific purpose in mind, requiring engineers to combine different EQ types in one signal chain in order to achieve the frequency response they needed on any given source. They would have to accept the necessary evil of the resulting phase and intermodulation distortion when treating these sounds. When released in 1961, the Klein & Hummel UE-100 Universal Equalizer changed all that.