Repace Diaphragms myself or send them to GPA?......

[sba2]

"...I feel that they lost some magnetism even though they are Ferrite/ceramic all magnets lose magnetism and the longer the period plus right conditions the greater the loss"

...Maybe on this planet...;

* -- What types of magnets are there?

[Altec Best]

[QUOTE=bfish;1806199]...Maybe on this planetE]


OK I bought a pair of speakers 27 years ago that have ceramic magnets they came in a styro/cardboard package they were placed magnet to magnet with a piece of foam in between them to keep the magnets apart if you took foam out and magnets stuck together they were hard to pull apart Not so Much ANYMORE are you telling me that they are just as strong as the day I bought them. I'd like to here this answer.By the way Happy New Year !!!

I talked to bill/gpa about this very thing and he said heat could do it,exposed to high temps and they were in my car for along time I don't know about you but my car gets to be about 150 degrees inside the car in the summertime that planet/sun wouldn't be that far off well maybe alittle

http://www.coolmagnetman.com/magcare.htm link courtesy of sba2 Thanks !!!

b. Heat
As the temperature increases, the molecules that make up the magnetic material, with their poles all lined up, will start to wiggle and jiggle around, causing the strength of the magnet to decrease. If allowed to go above their maximum working temperature, they will lose some of their strength and will not be able to recover it when it cools back down. If allowed to go above their Curie Temperature, they will lose all of their magnetic strength and will not be able to recover from it.
For ceramic and ferrite magnets, their maximum working temperature is 300 degrees C (572 degrees F).
The maximum working temperature for flexible magnets is about 180C (356F).
The Curie Temperature for ceramic and ferrite magnets is 460C (860F).
I'm not sure about flexible magnets since the binder starts melting around 200C (392F).
"Instead, keep your magnets cool".

My point exactly.Just because they are ferrite/ceramic doesn't mean they will never need a charge for most ferrite/ceramics that haven't been dropped,exposed to high temps,moisture,shock,etc...they should be fine but there is always the possibility that they will especially if bought from say ebay, who knows where they have been or what care they were givin.I absolutely babied my speakers I tried to keep them mint but how do you keep heat out of your car,especially when it's in the mid 90's during the summer.They lost alot of strength that much I CAN ASSURE YOU.But Bill said he can throw a charge on them regardless I have another set that I just got and they are twice as strong magnetically.If I had a way to measure I would.

[bowtie427ss]

OK I bought a pair of speakers 27 years ago that have ceramic magnets they came in a styro/cardboard package they were placed magnet to magnet with a piece of foam in between them to keep the magnets apart if you took foam out and magnets stuck together they were hard to pull apart Not so Much ANYMORE are you telling me that they are just as strong as the day I bought them.

What i would tell you is that they are of poor quality and do not represent the typical Altec, JBL, EV, and host of other OEM makers magnets. Also, when interaction between two magnets, even of the same type occurs, all bets on longevity/survival of magnetic charge are off.

EDIT: After looking at that pic, it occurs to me that they've seen 27+ years of improper handling/storage(no fault of yours). That is not how speakers are normally stored, probably wasn't foreseen by the engineers that the magnets would spend decades in storage improperly positioned in relation to each other. That was poorly designed packaging, someone should have known better. I would say you have encountered an "exception" to the rule.

Just because they are ferrite/ceramic doesn't mean they will never need a charge for most ferrite/ceramics that haven't been dropped,exposed to high temps,moisture,shock,etc..

For loudspeakers, if the ferrite is of high quality, it should indeed mean exactly that.

In terms of temperature, other critical parts of the speaker should fail long before 570F.

In terms of shock, proper alignment and structural failure of the frame should occur before demagnetization.

Now i'm well aware that ceramic and ferrite magnets begin their lives as a totally inert mass and must pass thru the gausser before they gain charge. Logic says that if it can be magnetized, it can be demagnetized.

But, IMO&E a properly made ferrite/ceramic speaker magnet used under normal operating conditions will never lose charge or need recharging.

In practical terms, you cannot discharge a well made ferrite/ceramic magnet without destroying the rest of the speaker in the process.

Just my .02 y'all understand.................

[bfish]

...I'd like to here this answer..

If you feel your ferrites need recharged, I'm sure someone out there will be more than happy to take your money.

I've talked to Bill too... in person... when I hauled a pickup load of Altec drivers to his shop for recharging. The first thing he did was sort the ferrites out and told me to load them back up because they wouldn't need it.

I'm not trying to convince you, you can believe what you want. However, since part of the purpose of this site is information, I just wanted to counter your comments for the benefit of readers who might not know any better. I tried to do it in a humorous way.

Added;
I can't help but be reminded of the "bag of hammers" line (1:22) from O Brother...;

[ame="http://www.spike.com/video/o-brother-where-art/656339"]O Brother, Where Art Thou? | SPIKE[/ame]


HAPPY NEW YEAR Y'ALL!

[valhallax]

gotta chime in on this one.. changinging the phrams is easy as pie. from what i understand, if you have a 288b that needs new ones, they will need to go to gpa for sure, something about machining. also, if anyone can back me up, or correct me if im wrong... i read once, a guy had run a sine wave signal, i think a 1k, to center the coil in the gap, instead of using the supplied shims. are there any benefits to this method? when i did mine, several pairs..i also cleaned out the gap with folded over scotch tape, to remove any old debris.
on the other hand, a friend of mine replaced his peavey diaphragms, and that company was kind enough to supply him with extra ferrite powder to help fill in the gap. best laugh i had in a long time. if there was ever any doubt to quality of altecs
by the way..bill's replacement parts sound soooo good! why shop anywhere else?

[Altec Best]

EDIT: After looking at that pic, it occurs to me that they've seen 27+ years of improper handling/storage(no fault of yours). That is not how speakers are normally stored, probably wasn't foreseen by the engineers that the magnets would spend decades in storage improperly positioned in relation to each other. That was poorly designed packaging, someone should have known better. I would say you have encountered an "exception" to the rule.
...

First off I want to apologize to Cut-Throat for this going off topic Tom they haven't spent the better part of decades in the package they were in my vehicles for over 24+ years in 4 differant vehicles and have been in the package(Original Packaging) for the last 2 or 3.You say well the ferrite must have been of low quality and I say they are the best sounding 6x9 speaker I ever heard and they are not of low quality I listened to alot of them they still crank but the bass is off abit.They are Altec Lansing.You say I encountered an exception to the rule well that is the point I'm trying to make When someone says Ferrites/Ceramics never need to be recharged I have to disagree for the most part 99% I would agree but it is always a possiblity that a speaker magnet could have lost a charge from what I understand from permanet magnets is that they are always trying to destroy themselves/demagnetize but just need a push from heat,shock,other magnetic feilds etc...The tempature your talking about 560F the maximum working temp but high temps much below that is enough for small loses and over time decades they can become quite noticeable what you spoke of decades.From my experiances I guess I'm just lucky


First I need to say that we don't need to get into a pissing match over this but from MY POINT OF VEIW,from my personal experiance they can and did lose magnetism.Your trying to tell me about my experiance with this pair of speakers Wow OK.I have the proof in my possession so you say 27 years of improper handling come on they were mounted in my vehicles for 24 years so how is that improper handling.For me it seems no matter where you go there are people who will say the glass is half full and others who will say no it isn't it is half empty that is nit pickin.Your saying that I'm the only one in the world that this has happened to too.So I'll say again from my point of view or IMHO that ferrite/ceramic magnets especially 20+ years old should be checked for discharge "IF NOT PERFORMING AS SHOULD", I noticed it when the bass response was significantly reduced.I have another pair just as old and they are like night and day differance.Just my .$02.... Let's put our $ .02 together and try to figure out how this happened I think that would be more useful on this forum to maybe help others who may have ceramics not performing as should but don't know why.But Thanks for your thoughts and help Lord knows I can use it.

I'am not Mr. Loudspeaker and you guys know alot more than me but I have a pair of ceramics/ferrite speakers that have discharged somewhat not total discharge but enough to notice a differance from when they were new.And would like to know why I thought I was taking care of them the best I could they are in mint condition physically.I have 2 identical pair and you would be more than welcome to check them yourself.Thanks

Anyway Tom Happy New Year Best Wishes for You and Yours !!!

[Altec Best]

[QUOTE=bfish;1806337]

I've talked to Bill too... in person... when I hauled a pickup load of Altec drivers to his shop for recharging. The first thing he did was sort the ferrites out and told me to load them back up because they wouldn't need it.

I'm not trying to convince you, you can believe what you want. However, since part of the purpose of this site is information, I just wanted to counter your comments for the benefit of readers who might not know any better. I tried to do it in a humorous way.

Hi B-fish, I know it was humorous and I appreciate it, but I have something that was not supposed to happen with ceramics and Bill said mounted in your car for 20+ years in heat of the trunk could certainly discharge them anything is possible.But he said send them in and he would check them if they need a charge he would do it if they don't NO Charge $$ (No pun Intended)but I don't mind supporting my favorite speaker shop.Ask him about heat and discharging so at most if they don't need it I'll be out $13 for shipping I can live with that.I wasn't pulling these comments out of the air I was just commenting on my experiance with this pair of speakers and they are both affected this is why i suspected the magnets heck to show you how much I know about them I thought they were Alnico they are from Anaheim plant so time frame was close.But Bill said the same thing they are ceramics and shouldn't need a recharge and then explained to him what model and car speaker they were and told him they were mounted in a car for 24 years and then that's when he said heat could discharge them especially exposed for that long in a trunk no big deal send them in,if there's a problem he can fix I said great.Just my experiance with it maybe Tom is right exception to the rule I don't know but sure would like to.


I won't just give anyone my money now

By the way I did get a chuckle as I was spiraling down to the sun in a blaze of glory Happy New Year

May Everyone Have a good year Best Wishes

[oface1]

Hey Altec Best...

I think by the time Altec was making 6x9's they were owned by Sparko-matic (someone correct me if I am wrong). That is when Altec was venturing out way into other territory that they did not have a lot of exp in, and the expense & quality of the items produced suffered under the automotive line....


-chris

[Altec Best]

Chris, Talk to Dsauro Dave worked at the Aneheim plant when they started the Voice of the highway line.Heres the thread

http://www.hostboard.com/forums/alte...hway-gems.html


No these were before Sparky got his dirty fingers on them it was around the time that they went to carbon fiber cones if I'm not mistaken that's when Sparkomatic came into the picture with the ALS line

[Panomaniac]

Well since we are on the subject of magnets...

I have been told that any Alnico can be recharged. Told that they can't be so beat that they won't improve with recharging. Hmmm... I had my 416-8As zapped twice and they barely budged. Still weak. So I am not ready to immediately believe what everyone "knows" about magnets, either.

Just my 2 cents.