After two and a half years and thousands of Phantom Piezo Preamps sold, we finally ran out of 2SK596S-C JFETs (which have been discontinued for some time by On-Semi). The only credible alternative going forward is to use the Fairchild PF5102 – now also an On-Semi product. To that end, we have slightly redesigned the Phantom Piezo Preamp PCB to allow for the use of the ‘5102 which has a different pinout to the ‘596 and also to incorporate a pair of zener diodes across the input to protect the input from large voltage spikes which can be generated by a piezo transducer if you give it a significant physical shock. As a result, the redesigned PCB is 1mm longer than the old one.

Apart from that, the design is largely unchanged. We have built prototypes and performance is excellent. The new preamps are up in the shop here and there is a version with the XLR not soldered here


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