Speaker construction and effect on sound

American Viking · 11-02-2009, 05:05 AM

Hello again. Curiosity has risen again and I have a few questions on some speakers.

I already own Marshall cabinets with G12T-75's and the day before Halloween I purchased two Ampeg cabinets with Vintage 30's (which are odd within itself because the whole cabinet is plywood except for the back baffle which is MFB). One of the V30's was bad and I detected an open circuit using my multimeter. To the best of my knowledge, I imagine the coil within the speaker must be severed or blown, so here are my questions...

If the coil has gone bad, how does one go about repairing one and is it worth it? What kind of machines/devices/tools are used to open and reseal the speaker?

If replacing a coil will this change the auditory properties of the speaker?

How does this happen in the first place? Improper impedance? Poor construction? Too loud? Too much power?

I am general interest in all this is peaked. After I read a little bit on the construction of the V30's and how Celestion wanted to build a speaker with a ceramic magnet that could rival the sound of an alnico magnet. Any thoughts on these as well? What's the big deal about alnico and does the price tag reflect quality or is it just the process of dealing with the elements to create the alnico?

Also if anyone has a 16ohm Vintage 30 made in England I need to buy one. On a side note all eight of the speakers had CELESTION INTERNATIONAL LTD. FOXHALL RD. IPSWITCH, SUFFOLK ENGLAND written on them. Does this mean they are made in England as others I see only have CELESTION INTERNATIONAL on them.

D.Dailey · 11-02-2009, 10:27 AM

Interesting Question..
Back in the early 70's I used to run two pairs of Utah's in my cabs with a 45 Watt Traynor Reverb master.
Home built, worked great..
But the cones would have about 3/4-1 inch of movement, in and out.
It was kind'a impressive to watch.
But when running a Big Muff and Crybaby, I got to where I was dystroying a voice coil at a rate of about 1-2 a year..
Thats when I switched to Celestion Greenbacks.. (probebly 1975)
Never managed to dystroy one and still have about 5 of them here..

What would usually happen to my Utahs was the voicecoil would get streached out of round.
If I carefully placed my four fingers and thumb around the voicecoil cover and gently pushed in, I would feel a raspy resistance.
If the speaker is allowed to run for long in that condition, the fine wires in the coil will eventually ware through. (Open Circit)
At that time I would pull the speaker and send it out for a re-cone.
I usually kept those for spares.
As sometimes the re-cones worked great, sometimes not..

I would bet you can have them reconditioned.
But as to the quality of the work?????
Would likely depend on someones ambition..

You might check the epoxy where the terminal leads connect to the voice coil.
I have repaired a couple of those by myself..

American Viking · 11-03-2009, 06:35 PM

bump

MajorNut1967 · 11-03-2009, 06:56 PM

Viking make sure the braided wire from the cone to the terminal isnt severed, that might be it?

nofearfactor · 11-03-2009, 07:31 PM

Does a city the size of Richmond have a speaker repair shop?

I have a couple of G12T-75s I want to have reconed or reconditioned myself. One(made in Ipswich,England) is from an 83' JCM 800 4010 combo and the other is from a 1960cab I bought and changed the speakers out. Theres a speaker repair guy in my town but getting one reconditioned probably costs about as much as just getting a new one from Warehouse Speakers.com.

American Viking · 11-04-2009, 10:34 AM

I'm pretty sure a company called Backstage can repair it, I just don't want to bother with it if it's going to sound greatly different when I get it back. If it's over a certain amount I could just buy a used Celestion or a new Warehouse speaker.

javier pintos · 11-06-2009, 02:54 PM

here´s some info on how they make an Alnico magnet, it seems more complex than ceramic magnets

Alnico Magnets

Ceramic Magnets & Ferrite Magnets - Dura Magnetics, Inc.

11-02-2009, 05:05 AM	#1 (permalink)
American Viking Senior Member Join Date: Jan 2009 Location: RICHMOND, VIRGINIA Posts: 1,510	Speaker construction and effect on sound Hello again. Curiosity has risen again and I have a few questions on some speakers. I already own Marshall cabinets with G12T-75's and the day before Halloween I purchased two Ampeg cabinets with Vintage 30's (which are odd within itself because the whole cabinet is plywood except for the back baffle which is MFB). One of the V30's was bad and I detected an open circuit using my multimeter. To the best of my knowledge, I imagine the coil within the speaker must be severed or blown, so here are my questions... If the coil has gone bad, how does one go about repairing one and is it worth it? What kind of machines/devices/tools are used to open and reseal the speaker? If replacing a coil will this change the auditory properties of the speaker? How does this happen in the first place? Improper impedance? Poor construction? Too loud? Too much power? I am general interest in all this is peaked. After I read a little bit on the construction of the V30's and how Celestion wanted to build a speaker with a ceramic magnet that could rival the sound of an alnico magnet. Any thoughts on these as well? What's the big deal about alnico and does the price tag reflect quality or is it just the process of dealing with the elements to create the alnico? Also if anyone has a 16ohm Vintage 30 made in England I need to buy one. On a side note all eight of the speakers had CELESTION INTERNATIONAL LTD. FOXHALL RD. IPSWITCH, SUFFOLK ENGLAND written on them. Does this mean they are made in England as others I see only have CELESTION INTERNATIONAL on them. __________________ -I'd rather be a good liver than have one...

11-02-2009, 10:27 AM	#2 (permalink)
D.Dailey Member Join Date: Oct 2009 Location: The Beer Tent Capital of the World (Muskegon , Michigan) Posts: 66	Re: Speaker construction and effect on sound Interesting Question.. Back in the early 70's I used to run two pairs of Utah's in my cabs with a 45 Watt Traynor Reverb master. Home built, worked great.. But the cones would have about 3/4-1 inch of movement, in and out. It was kind'a impressive to watch. But when running a Big Muff and Crybaby, I got to where I was dystroying a voice coil at a rate of about 1-2 a year.. Thats when I switched to Celestion Greenbacks.. (probebly 1975) Never managed to dystroy one and still have about 5 of them here.. What would usually happen to my Utahs was the voicecoil would get streached out of round. If I carefully placed my four fingers and thumb around the voicecoil cover and gently pushed in, I would feel a raspy resistance. If the speaker is allowed to run for long in that condition, the fine wires in the coil will eventually ware through. (Open Circit) At that time I would pull the speaker and send it out for a re-cone. I usually kept those for spares. As sometimes the re-cones worked great, sometimes not.. I would bet you can have them reconditioned. But as to the quality of the work????? Would likely depend on someones ambition.. You might check the epoxy where the terminal leads connect to the voice coil. I have repaired a couple of those by myself..

11-03-2009, 06:35 PM	#3 (permalink)
American Viking Senior Member Join Date: Jan 2009 Location: RICHMOND, VIRGINIA Posts: 1,510	Re: Speaker construction and effect on sound bump __________________ -I'd rather be a good liver than have one...

11-03-2009, 06:56 PM	#4 (permalink)
MajorNut1967 Senior Member Join Date: Jul 2009 Location: South Pacific Posts: 710	Re: Speaker construction and effect on sound Viking make sure the braided wire from the cone to the terminal isnt severed, that might be it? __________________ MJN1967 aka BA (Bad Attitude) 1968 model 1987 50watt. A Baby Major (Half-Power) I built from the ground up. JTM 45 Clone combo Ground up build. JCM 800 Clone Ground up build. Custom Built Warmoth Strat 75' Fender Tele-Deluxe '70 style strat custom build w/Custom Shop 69's PU's

11-03-2009, 07:31 PM	#5 (permalink)
nofearfactor Senior Member Join Date: Mar 2009 Location: Hellbillyville Posts: 179	Re: Speaker construction and effect on sound Does a city the size of Richmond have a speaker repair shop? I have a couple of G12T-75s I want to have reconed or reconditioned myself. One(made in Ipswich,England) is from an 83' JCM 800 4010 combo and the other is from a 1960cab I bought and changed the speakers out. Theres a speaker repair guy in my town but getting one reconditioned probably costs about as much as just getting a new one from Warehouse Speakers.com. __________________ myspace- http://www.myspace.com/nofearfactor some gear pics- http://community.webshots.com/album/...ecurity=QbSaeN

11-04-2009, 10:34 AM	#6 (permalink)
American Viking Senior Member Join Date: Jan 2009 Location: RICHMOND, VIRGINIA Posts: 1,510	Re: Speaker construction and effect on sound I'm pretty sure a company called Backstage can repair it, I just don't want to bother with it if it's going to sound greatly different when I get it back. If it's over a certain amount I could just buy a used Celestion or a new Warehouse speaker. __________________ -I'd rather be a good liver than have one...

11-06-2009, 02:54 PM	#7 (permalink)
javier pintos Senior Member Join Date: Sep 2008 Location: Mexico Posts: 323	Re: Speaker construction and effect on sound here´s some info on how they make an Alnico magnet, it seems more complex than ceramic magnets Alnico Magnets Ceramic Magnets & Ferrite Magnets - Dura Magnetics, Inc.

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