PLINIUS SA-Reference

The SA-Reference represents the flagship model in the Plinius’s catalogue. The highest rank is evidenced also through its dimensions (51w x 27,5h x 53d) and weight: nearly 130 pounds. It is two oversized toroid transformers and large heatsinks that are responsible for the SA-Reference’s mass. Peter Thomson is convinced about the necessity of having a separate power supply for each channel. It is interesting, however, that there are four huge transformers, along with pre-regulation components, to be found inside the SA-Reference to ensure the completely stabilized power supply.

What is special about the SA-Reference is that it provides a choice of listening either in the class A or AB. The switching is easily accomplished on-the-fly by a switch on the SA-Reference’s frontplate. Different pros and cons come along with both operation modes which is going to be discussed in a minute.

The other special feature is that the Plinius actually encourages users to get under the amp’s hood. With a screwdriver in your hand it is possible to make two fine adjustments: to dim two blue LED indicators on the SA-Reference’s frontplate and set how green (in terms of power consumption) the Plinius should be. Through the ‘ecologic jumper’ one can decide if the amp shall switch from A to AB within 15, 30 or 60 minutes while at idle. Not an unimportant feature if you consider hundreds watts you have to pay for due to high currents the SA-Reference draws in case of the class A operation.

The aesthetics of the Plinius are simple yet effective: there are only two small push-buttons on its frontplate (one is the aforementioned A/AB switch, the other mutes the output) plus a clear-cut logo and a serial number. The reviewed unit was proudly presented as no.200 which immediately raised my curiosity for who were the owners of no.199 and no.201. It is pity not to have the list of owners as a part of the amp’s documentation for I’m sure at least one of those numbers belongs to a beautiful audiophile girl.

The sides of the amp are occupied by large fractal-like cooler fins, the backplate carries one pair of balanced XLR and one pair of unbalanced RCA inputs, IEC inlet with the mains switch and quality speaker posts. A data bus connector (for system remote control) and a ground lift switch (to suppress possible humming in the symmetrical mode by disconnecting the signal ground from the amp´s chassis) are less usual.

The SA-Reference provides 450W into 4 ohms, 300W into 8 ohms respectively. Should you need more it is possible to switch the amp to MONO or bridge it to increase its output to 1 kilowatt – that is sufficient to move any speaker’s membrane. For sure I would not object to having two SA-References with 2x1000W of their output power available in my listening room.
All the above holds true about the class-AB operation. Transforming the amp into the pure class A drops the power to 100 watts per channel. Excess power requirements are not clipped, however, but the SA-References smoothly switches back to the AB above 100W to utilize its full potential.