| Originally Posted by AMB In addition to the left and right channels, in this amplifier the "ground" wire of the headphone is actively driven by a third channel of the same topology. The ground channel amplifier sources or sinks the return current from the transducers, which would otherwise have been dumped into signal ground or power supply ground. This shifts responsibility for the high current reactive load of the headphones from signal ground to the tightly regulated power supply rails, thus removing the primary source of signal ground contamination. The headphone transducer "sees" symmetrical output buffers with equal impedance and transfer characteristics on both sides, rather than an output buffer on one side and a capacitor bank of the power supply ground on the other. This results in lower output impedance and greater linearity. |
| Originally Posted by Mosel The PPA has 3 amplifier channels (left, right, and ground) which use the same output buffers and noninverting opamp topology. The ground channel sources and sinks the return current from both drivers which would otherwise have been dumped into signal ground or power supply ground. This shifts responsibility for the high current reactive load of the headphones from signal ground to the supply rails of the ground channel buffer, thus removing the primary source of signal ground contamination. The drivers have symmetrical output buffers with equal impedance and transfer characteristics on both sides, rather than an output buffer on one side and the large capacitor bank of the power supply ground on the other. This results in lower output impedance and greater linearity |
