The Klein & Hummel UE-100 tube equalizer is a rare professional unit that has become known for its musically warm curves and precision. The very characteristic sound of this German technology marvel of the 60’s is just amazing, and here we want to give a glimpse of its qualities.
The UE-100 version we used for this test is a faithful emulation made by Lindell Audio from the original hardware.
One of the particularity of this analog equalizer is that its manufacturing circuit allows a minimal phase shift and a transparent filtering of the low and high frequencies. It was often used at the time for pressing vinyls.
The audio excerpts below show the use of the high-pass filter at 40 and 60 Hz with a gentle slope of 12 dB per octave on a grand piano recording.
RAW (…just the audio signal passes through the lovely warm sound of the UE-100):
High-pass filter at 40 Hz:
High-pass filter at 60 Hz:
Of course, the choice of the cutoff frequency and the slope depends on the sound you want to obtain, and it is not always necessary to apply a high-pass filter on a piano.
In the audio sample below, we used 60 Hz high-pass filter with a 24 dB slope and a little bit of eq’ing.