magnetic pickup

[AnalogUniverse]

i started a thread in the "so much gear" forum and didn't really get the response i was hoping for... so i figured i'd bump it over to you folks.

http://gearslutz.com/board/showthread.php3?t=45644

any ideas would be greatly appreciated

[AnalogUniverse]

alright, one last bump on this before i start winding coils at random...

[tINY]

A guitar pick up would be a good place to start. A tape head will only pick up magnetic field variations verry near the gap. The problem with magnetic material in the middle of the windings is that you have hysterisis and saturation to deal with. This can get a bit tricky to get what you are after.

An air core might be the best for your needs. A short piece of 4 inch (10cm) ABS pipe with a couple thousand turns of magnet wire may work well. You will need to check the overall inductance and resistance of the pick up to determine how much high end you will get.




-tINY

[Geoff_T]

Originally Posted by AnalogUniverse

i started a thread in the "so much gear" forum and didn't really get the response i was hoping for... so i figured i'd bump it over to you folks.

http://gearslutz.com/board/showthread.php3?t=45644

any ideas would be greatly appreciated

Hi

Aeons ago I worked on electrical power switching equipment that included the London Underground. Back then (1960's) they used 660 volts dc for everything.

You could get some very interesting shocks off those kinds of voltages... very disabilitating!

Nowadays the trains are a little more high tech and use semi-conductor control but they always could use regenerative braking by complex switching.

As the carriage floor is right over the motors on the axles there must be some strong fields flying around but there are so many arcs and sparks on the commutators and track pick ups that I can't imagine how it would sound if you tried to record it! The noise would extend from LF to RF!

An interesting idea though!