802 Field Coil Drivers on Ebay

[BillWojo]

Link
Altec Lansing 802D Field Coil | eBay
I'm sure these will go high at the end. Anybody know anything about them? I'd like to try a set, to bad there are not any plans out there. I have a crusty set of 808's that would be perfect candidates.

BillWojo

[mah]

Bill, Here is a little weekend reading for you: Project Ryu - DIY Field Coil Loudspeaker - diyAudio

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Altec and WE field coil drivers are hard to find. I think this Korean guy has snatched them all:

Silbatone Acoustics

[Elitopus1]

I am also curious about those FC 802's. I have seen a few pairs for sale, but have never heard a pair. In fact the only FC speaker I have heard was an old 12" Jensen A12 from a Hammond organ.

I have heard people talk about the "magic" of FC drivers. I have also heard they have more distortion than permanent magnet drivers.

I guess I should find a pair to listen to and find out. Probably cheaper to get the pieces and make your own

[RonSSS]

They of course will require a nice quiet power supply to energize the coils.
I wonder what the specs for a supply would be?

Field coil speakers were used in all of the old radios from the 30's and 40's.
The field coil was actually the choke in the power supply. Served dual purpose.

I have an old Gilfilian table top 4 tube radio from the mid 30's that has a Lansing 5" speaker.

Ron

[westend9]

I have a pair of field coil woofers in an older Magnavox console. The best application of field coils that I've heard were a pair of custom speakers auditioned at the Mpls. Audio Society meeting. The builder had assembled two 15" woofers, a horn midrange, and a Fostex super tweeter in each cabinet. The power supply was a standalone rack system that he purpose-built for the drivers. It was a fairly impressive system! Price was impressive, too. I think he was asking around $40K for the whole enchilada.

I've never heard an Altec FC compression driver but I would think the physical construction and diaphragm would have more bearing on the presentation. It may be sweeter than honey, I wouldn't know.

[BillWojo]

Thanks Marshall, been reading that thread for the past few hours, lots of good info in there. A lot of it is over my head and I'm sure glad I don't have ambitions of building speakers from scratch. It gives one an idea of just how hard this stuff is to design. Really makes you appreciate what the engineers at WE and later at Altec had to go through, all with no computer simulations. Lot's of math, physics and a slide-rule.
My father was a structural engineer, built a lot of the great steel mills in this country and I can still remember him doing calculations on his slide-rule as a kid. He designed all the first "Continuous Casting" steel mills in the USA, steel went from furnace to rolling mill in one step. It was revolutionary.
From what I have gathered so far, making field coil drivers will be a lot easier that what they are doing. The magnetic pot structure is already in place, it just needs to be modified at the pole piece.
Not a project that I'm jumping into but at the info gathering stage.
Thanks so much for the link.

BillWojo