Crazy field coil thought

mashaffer · 13th May 2006, 05:40 AM

Has anyone investigated converting a PM speaker to field coil? Could one - as a practical matter - remove the PM from a driver and add an electromagnet in its place? Maybe using an older driver with the smaller magnets housed in U shaped frame (easier to remove than modern designs?)...

OK. I get some odd thoughts at 1:45 AM... Maybe I should go to bed.

mike

lndm · 13th May 2006, 06:17 AM

Crazy thought number two, this is a way to introduce a potentially useful feedback option.

Raoul · 13th May 2006, 11:18 AM

Funny, I was just talking about that very idea with a friend of mine earlier tonight. Guess it must be a hundredth monkey thing...

dwk123 · 13th May 2006, 05:58 PM

I spent some 'thought experiment' time on this and while I think it's possible in theory, in practice it may not be the ideal way to go. Reasons
- tough to get the magnet off without wrecking the cone
- voice coil design probably should be different for a field coil unit (not an issue if you're just trying to make something work)

On the other hand, I'm not sure how else you'd go about experimenting. You either need to remove a magnet from a working speaker, OR be able to get the cone/spider out without damaging it to serve as the basis for the field coil unit. Maybe the way to go is to look for drivers that are easily disassembled - some pro units may fall into this category.

ocool_15 · 15th May 2006, 02:26 AM

Depending non the size of driver wouldnt it be easier to buy a passive radiator and make the voice coil/former since your making the field coil. Though I've had trouble finding passives any smaller then 8", a large speaker may be easier to work on at least for the initial stages...

lndm · 15th May 2006, 02:53 AM

What about a DIY ribbon?

Variac · 15th May 2006, 04:07 AM

Peavey makes "pro" drivers with a magnet structure that can be unbolted. You can buy the metal "basket" with cone and suspension attached as a spare part. Might be an easy way to get started, but I suppose that you were thnking of using a driver that is already considered among the best. Idon't know how the Peaveys sound.

tom1356 · 15th May 2006, 04:51 AM

Someone is doing just that...
http://www.shindolabs.com/pages/5/pa...=1112334014765

Variac · 15th May 2006, 05:49 AM

Shindo is converting a driver to field coil?

There are other companies that make field coil drivers.

I think Mike wants to make his own, no?

tom1356 · 15th May 2006, 02:03 PM

Shindo is converting old Altec (288) and JBL (375/6) into field coils.

13th May 2006, 05:40 AM	#1
mashaffer diyAudio Member Join Date: Jun 2004 Location: Indiana	Crazy field coil thought Has anyone investigated converting a PM speaker to field coil? Could one - as a practical matter - remove the PM from a driver and add an electromagnet in its place? Maybe using an older driver with the smaller magnets housed in U shaped frame (easier to remove than modern designs?)... OK. I get some odd thoughts at 1:45 AM... Maybe I should go to bed. mike

15th May 2006, 04:07 AM	#7
Variac diyAudio Editor Join Date: Dec 2001 Location: San Francisco, USA	Peavey makes "pro" drivers with a magnet structure that can be unbolted. You can buy the metal "basket" with cone and suspension attached as a spare part. Might be an easy way to get started, but I suppose that you were thnking of using a driver that is already considered among the best. Idon't know how the Peaveys sound. __________________ Burning Amp Festival Sunday, October 28th, 2012 in S.F. We need Volunteers & sign-up's for what you're bringing!

15th May 2006, 04:51 AM	#8
tom1356 diyAudio Member Join Date: Mar 2002 Location: boston	Someone is doing just that... http://www.shindolabs.com/pages/5/pa...=1112334014765 __________________ My "cult-like" following is accepting applications.

15th May 2006, 05:49 AM	#9
Variac diyAudio Editor Join Date: Dec 2001 Location: San Francisco, USA	Shindo is converting a driver to field coil? There are other companies that make field coil drivers. I think Mike wants to make his own, no? __________________ Burning Amp Festival Sunday, October 28th, 2012 in S.F. We need Volunteers & sign-up's for what you're bringing!

15th May 2006, 02:03 PM	#10
tom1356 diyAudio Member Join Date: Mar 2002 Location: boston	Shindo is converting old Altec (288) and JBL (375/6) into field coils. __________________ My "cult-like" following is accepting applications.


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

13th May 2006, 06:17 AM	#2
lndm diyAudio Member Join Date: Mar 2006 Location: nsw	Crazy thought number two, this is a way to introduce a potentially useful feedback option.

13th May 2006, 11:18 AM	#3
Raoul diyAudio Member Join Date: Feb 2003 Location: OR	Funny, I was just talking about that very idea with a friend of mine earlier tonight. Guess it must be a hundredth monkey thing...

13th May 2006, 05:58 PM	#4
dwk123 diyAudio Member Join Date: Feb 2002	I spent some 'thought experiment' time on this and while I think it's possible in theory, in practice it may not be the ideal way to go. Reasons - tough to get the magnet off without wrecking the cone - voice coil design probably should be different for a field coil unit (not an issue if you're just trying to make something work) On the other hand, I'm not sure how else you'd go about experimenting. You either need to remove a magnet from a working speaker, OR be able to get the cone/spider out without damaging it to serve as the basis for the field coil unit. Maybe the way to go is to look for drivers that are easily disassembled - some pro units may fall into this category.

15th May 2006, 02:26 AM	#5
ocool_15 diyAudio Member Join Date: Nov 2004 Location: sk	Depending non the size of driver wouldnt it be easier to buy a passive radiator and make the voice coil/former since your making the field coil. Though I've had trouble finding passives any smaller then 8", a large speaker may be easier to work on at least for the initial stages...

15th May 2006, 02:53 AM	#6
lndm diyAudio Member Join Date: Mar 2006 Location: nsw	What about a DIY ribbon?

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Has anyone DIY a Field coil?	OzMikeH	Full Range	18	16th November 2010 01:56 PM
New 15" Field Coil Speaker	deadlyvj	Full Range	2	6th June 2008 03:40 AM
The field coil revisited...	Rocky	Full Range	2	16th May 2006 02:56 PM
Looking for jensen field coil	Kris9999	Multi-Way	2	10th February 2006 04:31 PM
What's a Field Coil Amplifier?	krzanik	Tubes / Valves	9	14th May 2005 03:22 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read