RUPERT NEVE DESIGNS PREAMP MICROFONE Portico 5012

The microphone input is balanced but not floating, being a variant of an instrumentation amplifer using a “Transformer-Like-Amplifier” (T.L.A.) configuration with a toroidal Common Mode Rejection Low Pass Filter that excludes frequencies above 150 kHz. The T.L.A. is followed by an actual input transformer permitting a full +25 dBu input signal to be handled at unity gain without an input pad over the whole audio spectrum. This combines the advantages of both an “Electronically Balanced” and true transformer input. When the Phantom voltage is switched off, this input serves as a very high quality line input with an impedance of 10,000 ohms.