LABORATORY TEST REPORT

Newport Test Labs measured the power output of the Gryphon Essence Stereo power amplifier at exactly 51-watts per channel into 8 at all audio frequencies and irrespective of how many channels were driven: one or both. When driven into 4 loads, the Gryphon Essence’s power output doubled, which is exactly what a ‘perfect’ amplifier should do, but so few actually really do when tested. Again, the output was exactly 102-watts per channel at all audio frequencies irrespective of how many channels were driven, as you can see from both the accompanying bar graphs and the tabulated chart.

The Gryphon Essence very nearly pulled off the same trick again when Newport Test Labs dropped the load resistance to just 2 , but instead of delivering the theoretical ideal of 204-watts, the amplifier’s output instead topped out just four watts shy of that figure, delivering exactly 200-watts per channel, again at all audio frequencies and irrespective of the number of channels driven. Although this figure was just short of the theoretical ideal, it was bang-on Gryphon’s specification.

I need to emphasise at this point that these are absolutely fantastic results for a Class-A amplifier stage. It is an extraordinarily hard task for any amplifier designer to build a Class-A amplifier that will do this… just ask two of the world’s pre-eminent amplifier designers, Doug Self or Nelson Pass!

The frequency response of the Gryphon Essence pre/power duo was excellent, and remember that this is the response for both the pre-amplifier and the power amplifier combined, not individually, which is how the manufacturer lists the specifications. As you can see from the tabulated figures, Newport Test Labs measured the frequency response at less than 1Hz to 113kHz –1dB, and at less than 1Hz to 217kHz –3dB. Once again, this is outstandingly good performance.

Graph 1 shows the frequency response between 20Hz and 50kHz (again with both the pre and power amplifiers in the test loop) when driving a standard laboratory test load (an 8 non-inductive resistor) and when driving a load that simulates the one that would be presented by a two-way bass reflex loudspeaker (Newport Test Labs uses the same load for this test as Stereophile magazine: a load designed by Ken Kantor that John Atkinson modified to include Zobel impedance compensation in the treble).

The black trace on this graph shows the frequency response into a standard 8 non-inductive when the amplifier is in

Graph 4: Total harmonic distortion (THD) at 1kHz at an output of 1-watt into a 4-ohm non-inductive load, referenced to 0dB. Class-A mode.

Graph 2: Total harmonic distortion (THD) at 1kHz at an output of 1-watt into an 8-ohm non-inductive load, referenced to 0dB. Class-A mode.

Graph 3: Total harmonic distortion (THD) at 1kHz at an output of 1-watt into an 8-ohm non-inductive load, referenced to 0dB. Class A/B Mode.

Graph 1: Frequency response at 1-watt into an 8-ohm non-inductive load (black trace-Class A, red trace-Class-A/B) and into a combination resistive/ inductive/capacitive load representative of a typical two-way loudspeaker system (blue trace-Class A, purple trace Class A/B).