Nice Xmas gift! If you ever move to Europe you must bring those babies with you. Would love to have a listen. By the way... how do they sound?
Huge Karma points to KBI
Absolutely, KBI is the man!
Sound of these babies is pretty fun, compared to the E-25Ω they have a substantial roll-off up top, there seems to be a lot of missing information up top. The bass was an eye opener, compared to the E-25Ω these have more impact, they extend better, much better. The bass on these is great. Mid-Bass gets some impact, I noticed one peculiar characteristic in relation with compression pressure of the pads, at a certain point the Mid-Bass gets quite crazy, gains tons of impact. This is not apparent on the E-25Ω from 1989. Perhaps the tensile strength of the membrane of these very early DT48s was less than the later one's, I can't say. The Lower Mid-Range lacks the body. Slightly thinner than the Es.
In terms of the "Esoteric" differences as Dale would say, the Mid-Range is more resolving than the Es. Maybe more detailed, I don't know. DT48s are pretty detailed as is, can you really get more?
The excursion, if we go by the date 1939..a DT48A with 75 years of Burn-In hits much faster than my '89 E. For instance I'm sure the '89 E will never quit at 30Hz until it reaches max SPL and dies.
Due to the very early headband, same as the 2nd Berlin. It was designed for the rubber pads so there is limitation to get a perfect seal due to modern Earpad obstruction. I'm not getting the best seal.
I would not put the DT48A up against the HE-60s I heard, the E is the worthy contender for that overpriced E-Stat Sennheiser.
Technical Experience with 5Ω
I remember Dale mentioning that the DT48 doesn't really care about Under-Damping, my OTL at LG-3.5Ω Ouput Impedance at HG-10Ω. There was a lot of clipping at medium SPL.
So I plugged it into my SS, 10Ω OI. Gone was the clipping. The abnormalities were coming from nasty tubes. SS is the way to go. I will be getting a Beyerdynamic A20 - 100Ω OI to match the suggested Source Impedance standard.