Compared to the Krell KSA-300S power amplifier that I also review this month, the KRC preamp's design is, at first glance, almost conventional. But its thoroughly high-end internal design has been equally well thought-out and executed. Its main, four-layer, glass-epoxy circuit board is for the audio signal, DC power, and groundtwo layers for the latter are said to minimize noise. The gain stages are pure class-A and complementary. As in the amplifier, the circuit is direct-coupled, with servo circuits controlling the DC offset. The fully regulated power supply is housed in an external chassis. Seven inputs are provided: four single-ended, two balanced, and one single-ended tape. All inputs are line-level except for the optional, single-ended phono stage. (This review will address the line stages; a Follow-Up will discuss the phono stage's operation.) There are three outputs: balanced and single-ended main outputs, and a single-ended tape output.
Compared to the <A HREF="http://www.stereophile.com/solidpoweramps/krell_ksa-300s_power_amplifie… KSA-300S</A> power amplifier that I also review this month, the KRC preamp's design is, at first glance, almost conventional. But its thoroughly high-end internal design has been equally well thought-out and executed. Its main, four-layer, glass-epoxy circuit board is for the audio signal, DC power, and ground—two layers for the latter are said to minimize noise. The gain stages are pure class-A and complementary. As in the amplifier, the circuit is direct-coupled, with servo circuits controlling the DC offset. The fully regulated power supply is housed in an external chassis. Seven inputs are provided: four single-ended, two balanced, and one single-ended tape. All inputs are line-level except for the optional, single-ended phono stage. (This review will address the line stages; a Follow-Up will discuss the phono stage's operation.) There are three outputs: balanced and single-ended main outputs, and a single-ended tape output.