I pullked the 1005b/288b off the shelf where it had been sitting. When I originally unpacked and tested this one, it sounded distorted. I put it away and didn't screw with it, and was hoping it was just some dirt in the gap/'phragm.
The raw material complete with 50+ years of dust.
Here's a surprise - a loading cap. The screws on the cap all had that little "snap" to them when loosened, making me pretty confident that no one had been in this driver before.
Show me the money! A pristine 288b diaphragm. I didn't see the model number, but I've not found a model number listed for the 288b 'phragms. A pair of 20221s for the 288c went for over $600 on E-Pray last fall, and this one's in better condition than those - not that I'm ever going to sell....
I gently blew out the driver itself and was rewarded with a noticeable puff of dust. I carefully reassembled it, plopped a 7 uF capacitance in series with the + lead, and carefully applied some low wattage music.
Success! The distortion I once heard is gone. So I should be in good shape for Pano this weekend. Oh yeah, DCR on this guy is 14.2 ohms, so it's a real 20-24 ohm 'phragm.
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