FirstWatt SIT4

We've got a SITuation – It's FirstWatt's SIT-4 [$5'000] with two industrial-grade transformer-coupled Tokin THF51s static induction transistors rated for 600V, 30A, 400W and 50MHz bandwidth. In the typical FirstWatt enclosure, output power for these devices is limited by the size of the heat sinks. The SIT-4 circuit is single-ended class A and delivers 10/5wpc into 8/4Ω with an output impedance of 4Ω, 20dB of voltage gain and 6dB of negative feedback.