How do I know if I should get one of the old Power Scale Kits or the new DC Power Scale Kit? Is there an advantage to the old ones?
The DC-PSK is much easier to install, so an average tech can likely handle it. The Power Scale control itself can be located anywhere on the chassis as it carries filtered DC and therefore cannot interfere with any audio signals. DC-Power Scaling is better suited to multi-channel amps than the old-style PSKs are. This is especially true if multiple PS controls are desired, or when Power Scaling is to be used only with one preamp channel. Power transitions are instantaneous with the DC-PSK, where the older circuit required a fast-transition circuit to get a “reasonable” but not as quick transition. The old-style PSK-1 for fixed bias amps and PSK-2 for cathode biased amps operate with pulsating DC, which is very noisy. Wiring layout and component placement is trickier, and can highlight faults already existing in the amp’s wiring. This takes a very talented tech to install, and our list of recommended PS-installers have a lot of experience and creativity. The old-style PSKs work well for
