We looked at LDR products, and Kits seemed to be missing, certainly there were single input models and others using relays to switch audio outputs, but to our thinking not many strangely were building these to get the best audio from an LDR. We were excited with the wonderful audio LDR's can produce. and filed a patent for the control board as it achieves low voltage between 1.9v and 1.4v with sufficient current, whilst operating as a L pad potentiometer.
We listen carefully with the ESL57's to get the best sound. Before shipping a Kit we then tailor 3 parts on each control board to refine further still.
The kits comprise a assembled Control Board, a assembled LDR Output Board, a Bourns potentiometer, and switch for the 3 input edition. There is NO signal switching, rather the anode of the LDR simply switches on or off, to select or deselect that input. Dorothy and I carefully select NSL32SR2 or NSL32SR2S LDR's to individually match a Series and Shunt pair so you achieve matched pairs of devices. This makes a big difference to stereo balance. Eight LDR's are used for 3 inputs, six for the series and two for the shunt elements.
To get our kits up and running you will need, cable, a 12v regulated power supply, or 12v battery and charger, casework, a few hours, a screwdriver, a soldering iron and ideally a multimeter to check DC polarity. Optional is an additional capacitor for the power supply once polarity is confirmed and if soldering is difficult we can supply a 5mm pitch connector to get you going with 1 input, until soldering gear can be obtained.
Thank you for your support. We look forward to answering any questions you may have.
LDR Preamp Single and 3 Input Kit
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