Rare example of the Mk III version of this nice dual mono class A headphone amplifier - Welwyn resistors, LM6171 op amps, ALPS blue Velvet potentiometer. There are positive reviews/comments on the Mk 1 and 2 on the Rock Grotto website. I've kept this in preference to a Heed Canamp and it was pretty much on par with a Lehmann (Rhinelander?) I auditioned. Very clean and dynamic. £110