Pete Cornish doesn’t like true bypass: http://petecornish.co.uk/case_against_true_bypass.html
So inside all of his pedals he includes a buffer to aid the switching process and act as a line driver for the remainder of the pedal chain. He sells these individually as the LD-1 (and LD-3 with the mute switch and tuner output).
Here’s a description from the Cornish Website:
“Our low noise discrete component Class A pre-amplifier has been specifically designed to overcome the problems often encountered with amplification of Electric Instruments fitted with magnetic transducers.
A frequent cause of these problems is the mismatch of the impedance in the electrical circuit between the pickup and subsequent equipment: this mismatch has been completely eliminated with the introduction of our LD-1™ Line Driver.
The input impedance is identical to a high quality tube amplifier and our Class A Pre-amplifier also features a highly effective RF filter which will help prevent interference from nearby radio transmitters.
The pickup output should be connected directly to the LD-1™ input with a low loss, screened cable; the LD-1™ output can now be fed to any effects or volume pedals (if used) and then on to the amplifier, using fully screened cables throughout.
A further use of the LD-1™ is to isolate long cable feeds which can cause signal and tone losses at the end of an effects chain, particularly if the final effect has a high impedance output (for instance a 250KW foot volume pedal). When using many effects it can be beneficial to add a LD-1™ mid way along the chain thus preventing a build up of signal losses that can occur with mismatched impedances between effects.”
Well, someone’s taken a few Pete Cornish pedals apart and here’s the schematic for the buffer:
And here’s a vero layout from IvIark (http://tagboardeffects.blogspot.com):
