Can I use a class D amplifier with a Tube pre-amplifier?

Fundamentally, there is no inherent issue with using tube preamplifiers. However, many tube preamplifiers are designed to pair with tube power amplifiers, which are typically AC coupled. Consequently, some tube preamplifiers lack the necessary safeguards against turn-on and turn-off transients.

In certain cases, these preamplifiers may output their full anode voltage during power cycling. This can cause significant stress on connected equipment, as we have observed that a notable number of repairs result from tube preamplifiers discharging their output capacitors into the UcD™ input circuitry. It is important to note that such behavior is problematic for most solid-state amplifiers, not just UcD™ or NCORE® models.