Sugden writes: “The Masterclass FPA-4 Power Amplifier is considered by many of our customers as the baby gem in the Sugden Masterclass series. At almost half the price of the SPA-4 it offers an excellent value to performance ratio. The design is based on the A21 output stage but has been heavily upgraded with a comparator and correction circuit. This controls and corrects errors that can occur in the power stage due to varying loads, to match the output of the high impedance input amplifier.
In sonic terms this means the FPA-4 is capable of retaining its sound characteristics right up to maximum output without any noticeable compression or strain.”