Sorry to change the subject (I'm blessed with being English (quarter Italian !) but have some very smart American (New England) cousins)
I have just come across a' Hifi Yearbook' from 1975 picked up from the Hifi shows, in Harrogate, I visited with my dad at the time. Among the headphones listed are the the DT100s priced at £17.11 and DT48s (already a 37 year old design at the time) at £45. The other Beyers were DT96, DT100RR (with volume control), DT480, DT900 & DT900RR.
Thats one of the great thing about Beyer, their longevity with 100s still being an industry standard after all these years. The company doesn't change its headphones every few years, unlike even Sennheiser (hd25/600/650 excepted). They aren't into fashion they just make serious headphones still hand built in Germany.
The most expensive phones in the book were Koss ESP9 electrostatics at £79,more expensive than Stax at the time.
My dad bought a pair of Koss HV/ILC 'High Velocity' phones which were still in use some 25 years later when I bought the DT231s. They had individual volume controls on each cap. I remember listening to those hifi test LPs of the time : DSOTM and Tubular Bells and being blown away by the experience. They would probably sound terrible now though !
Edited by godbluff - 5/29/14 at 8:37am