Hoffman Amplifiers Tube Amplifier Forum
Other Stuff => Cabinets-Speakers => Topic started by: Terry on September 14, 2009, 08:25:30 am
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They say they are Jensens. They have tiny tiny magnets These are the numbers: 220338 AO21075O (or Q). Please let me know. I'm assuming the tiny magnets would mean very low headroom. Thanks
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Built by Jensen in the 38th week of '53 or '63. Here's more info: http://www.provide.net/~cfh/pots.html
http://www.webervst.com/codes.html
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Well tiny magnets usually mean Alnico in that era..... The magnet need not be very big to work well. It's worth trying them out for sure...just test for open voice coils with the ohmmeter first.
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Look at the magnet structure- I'm pretty sure you will see a piece of 1.5"-2" 1/4" flat bar stock bent in a square shape with a round piece of metal could be cast or made out of round stock in the middle (that's the alnico slug) the square box channels the magnetic flux to the gap. Ceramic motors look different- they are round and flat with a piece of grey-black ceramic material sandwiched between the two metal pole pieces. Rear piece has a piece of round stock press-fitted in the rear. with a date code of '53 or '63 my nickel is gonna be on the alnico magnet. Alnico didn't start going scarce until the late '60's. High-end speakers (Altec, WE, JBL, Stephens etc) used a different design- the motor was cast and machined from one piece instead of being punched out from flat stock.
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No. Thats just it. They don't look like that. There is no square box around the round thing. These just look like a (for lack of a better word) nipple on the back of the speaker....and they are tiny. The guy said there was 9 (count them...9) of these connected to a single organ. Oh boy...this is getting scarry.
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Hmmmm.... nipple on the back of the back of the speaker? That's the economy-economy version! Might be good for 12 watts max- If there was an amp with a couple of 6L6's and or a quad of 6V6's- the organ would have needed them all! Xmax is probably 2mm max.
I'd use them for single end amps like champs or bronco's... may have 'tone'