Jadis JPP-200 Pre-Preamplifier

I will be grateful for sharing any experience with this rare Jadis unit JPP-200 Pre-Preamplifier.

In fact it is an active head amp allowing to connect MC cartridge to MM phono input of preamplifier.

I am especially interested hoh compares MC cartridge connected directly to MC input of JP80MC or JP200MC preamplifier vs. MC cartridge connected to MM input via JPP-200 head amp.