Rim shape is described for each individual model. Model numbers progress numerically from model #1 with the largest cup diameter, to model #20C with the smallest cup diameter.
Cup depths are notated with letters. "A" cups are the deepest; standard cups have no letter designation; progressively shallower cups are marked B through F.
"A" Models have very deep cups, #24 backbores, and emit a large, dark sound.
Models with n...