Description

While the stock Moreplay circuit offers exceptional performance with a simple circuit and straightforward build, we felt improvements could be made with some upgrades. Where we have traditionally modularized these upgrades to allow individual modules to be compatible with other kits, the Moreplay instead receives its own set of customized PC boards optimized for this specific application.

The first portion of the upgrade features a PC board with a Schottky rectified low voltage DC supply feeding a pair of individual DC regulators to heat each 6V6, a high voltage regulator, and a pair of C4S current source loads. The regulated DC heater supplies remove the 60Hz heater hum and harmonics from the 6V6 tubes for a quieter background. Likewise, the high voltage DC regulator provides substantial power supply ripple rejection as well as isolating the large electrolytic capacitors from handling signal current. The pair of C4S constant current source loads provide twice the impedance to the 6V6 tube plates compared to the stock plate loading resistors, which reduces distortion and provides a slight (2-3dB estimated) increase in gain.

The second portion of the upgrade replaces the volume and balance pots with a pair of Alps RK27 Blue Velvet potentiometers. These have been a popular upgrade choice with our builders for many years, though they require PC board mounting. The substitution of the Alps balance pot removes 4dB of insertion loss present in the stock balance control design.

As with all of our upgrade kits this one is intended to be installed into a completed and fully functional basic version of the kit.