Here's an interesting set of response charts from a pair of 1936-1941 era audio interstage transformers, designed for single plate to dual grid use at a max level of 0 dBm. These are small units meant for portable use, similar to the UTC A series, but slightly smaller. The two pieces came from two different sources, and I'm more than pleasantly surprised by the response, and blown away by the matching between the two. Who says 1930's audio was crude?
Full size here
Full size here
