Hi Douglas
Partridge Type C-Core, with 10.000 Ohm primary, and 8x 1.7 Ohm secondaries which can be strapped for: 1.7,6.8,15.3,27,42.5,61,83,109 Ohm.Both are strapped at 27.Originally they worked in a private home single mono audio system.One amp for HF and other for LF,that is why they have...