Ok - here is the explanation on the umbilicals.
There are 2 cables that go from the PSU to the preamplifier. The first one (the larger of the 2) is a 9 pin cable that carries the high voltage, filament voltage , output signal ground and in the case of the Tape preamp - the negative rail for the LTP. This cable is made up of 4 shielded 2 conductor cables and a single larger conductor for output signal ground. All of these cables are teflon insulated, silver plated copper and are built for aerospace use. These are all bundled inside an overall tinned copper braid so that all the power supplies are double shielded. The pigtails that plug into each chassis are the safety earth that goes to the ground pin of the iec power receptacle. This way, it is possible to lift signal ground without compromising safety. The smaller PSU cable is a 4 conductor double shielded cable for the bipolar voltage supplies in the head amplifier or the MC section amplifier in the case of the Phono stage. This arrangement allows the construction of a true star ground for audio. The benefits are: no ground current modulation of the very sensitive head amplifier stage by the much larger currents of the output stages. Its a pain to hand build these umbilicals but it pays off in extremely low audio ground plane impedance and the ultimate goal of better sound. Also, i can accomodate custom lengths if needed. I never thought that my cable construction would require explanation but I'm glad to do it.
There are 2 cables that go from the PSU to the preamplifier. The first one (the larger of the 2) is a 9 pin cable that carries the high voltage, filament voltage , output signal ground and in the case of the Tape preamp - the negative rail for the LTP. This cable is made up of 4 shielded 2 conductor cables and a single larger conductor for output signal ground. All of these cables are teflon insulated, silver plated copper and are built for aerospace use. These are all bundled inside an overall tinned copper braid so that all the power supplies are double shielded. The pigtails that plug into each chassis are the safety earth that goes to the ground pin of the iec power receptacle. This way, it is possible to lift signal ground without compromising safety. The smaller PSU cable is a 4 conductor double shielded cable for the bipolar voltage supplies in the head amplifier or the MC section amplifier in the case of the Phono stage. This arrangement allows the construction of a true star ground for audio. The benefits are: no ground current modulation of the very sensitive head amplifier stage by the much larger currents of the output stages. Its a pain to hand build these umbilicals but it pays off in extremely low audio ground plane impedance and the ultimate goal of better sound. Also, i can accomodate custom lengths if needed. I never thought that my cable construction would require explanation but I'm glad to do it.
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