993 Stereo Hybrid Effektforstærker 125W

All the 993's voltage gain is provided by a 6H6П super tube. This Russian military triode has been selected for exceptional performance at audio frequencies, having both high transconductance and low mu. The valve operates in Class A in a grounded grid configuration with zero negative feedback for maximum fidelity.

Power supplies for the driver stage are fully discrete and shunt regulated for excellent transient response. The valve has an easy load, only driving the input of the output stage. This enables it to deliver the musical flow and micro detail that makes valves so special.

The 993 takes the unusual step of specifying a choke input power supply for the output stage. The choke is nearly as large as the power transformer and plays a crucial role in the amplifier's performance. The electrically noisy, high current spikes that are pulled from the mains in conventional supplies are avoided. The addition of a choke allows a much more linear current draw instead, keeping dynamic noise under drive much lower. Premium reservoir capacitors and soft recovery diodes complete the power supply.

The first watt delivered by an amplifier is the most crucial. It is where the majority of tonal and spatial cues reside at normal listening levels. The 993's output stage uses a small and agile output FET to serve this region, giving superior performance where it has most impact. When current demand rises, higher power bipolar devices supply additional current to move the loudspeaker with ease. The amplifier has zero global negative feedback, but because of high bias, still exhibits a low output impedance.

As with all Trilogy products great care has been taken with physical construction. The custom heat sink is milled from a solid billet of aluminium. The substantial mass has high thermal inertia, allowing the directly mounted output devices to operate at a constant temperature, free from the severe mechanical resonances of conventional extruded heat sinks.

Trilogy specifies quality parts throughout to ensure the 993 gives a lifetime of reliable performance. From precision resistors from Welwyn, custom capacitors and magnetics to Mundorf solid copper binding posts, used to eliminate the audible mechanical resonance of more common brass. Every construction detail has been carefully considered.