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previous: jj was looking at a book on building i... -- 7/30/2003 7:26 PM View Thread

Re: laminated core

8/3/2003 8:53 AM
Fred Hammon
Re: laminated core
I have just finished doing some pre-production prototypes of the Hagstrom(Guild) single coil bass pu used in the '60s. (Starfire basses) It's actually a varition of an old DeArmond guitar pu design.  
This single coil uses steel laminations with low carb. steel pole pieces running through holes in the laminations with bar mags. on either side. The steel lams apparently reduce eddy currents and create some sort of hystersis which stores energy and releases it slowly causing a sort of "soft knee effect" ( I don't really understand this shit) Nice in bass pickups though.  
I'm quoting Rick Turner here:  
"The laminations are important as is the insulating layer of varnish between them, and it's not due to hysteresis (nor hysteria), it's to reduce eddy current losses in the pickup itself. Basically, because the pole piece mass is electrically conductive, the pickup (or transformer, etc.) will develop electrical eddy currents within the pole stucture which run exactly opposite the current generated in the coil, thus cancelling out some of the coil's output. You go solid core with that and you'll decrease the output"  
Anyway, prototype pickups turned out very nice. Sound great. Got thumbs up from the right people. I'd be happy do enter a discussion with anybody about these jewels who's interested. I'm starting production "Full Tilt Boogie" next week. I've had some help from you all here so "Thanks"  

jgraham i'd like to know more.JGrah... -- 8/3/2003 12:56 PM
Sheldon Dingwall "The laminations are important as i... -- 9/4/2003 4:26 PM