I can't say enough good things about Studio Electronics, their gear, or the 4075 filter.
This was a birthday gift and Greg at S.E. helped me with all my questions and made sure It shipped in time.
I put the filter in, and was completely blown away.
I used Arp 2600 synths back in the 80's, and know the sound well.
The filter has every bit of the honking brassy sound of the original 4072 filter. First thing I did was Edgar Winter's Frankenstein. The filter totally nailed the sound of the synth break towards the end. Everything from brass patches to the haunting "Close Encounters" sounds were spot on to an ARP filter.
The build quality is impressive. Clean solder joints and lots of discretes.
Nice that it fixes the 12Khz limitation of the original. The drive control pushes the filter to misbehave wonderfully, at high settings.
I highly recommend this filter.