Magnetization

**David Deratany** · September 1st, 2003, 05:18 PM

Well, you can speculate; but for not a lot of money you can rid yourself of uncertainty by having them remagnetized by Great Plains Audio. I had my 802D's done there and the cost, including UPS to New England was somewhere around $35.

Even if their prices have changed since then, it would still be a small price to pay for peace of mind.

**Fitts** · September 1st, 2003, 10:40 PM

I'll second Dave's advice, I sent a 291 driver out to Bill and got all 27 pounds of magnet back at a very reasonable cost.

One thing you should be aware of is that the Alnico magnets in Altec drivers are very heavily shielded. You are not going to feel any great magnetism like you do with ferrite or ceramic magnets except right in the gap.

Happy listening,

**drongo** · September 2nd, 2003, 03:36 AM

I have a pair of 808A drivers, that on inspection, to me appear to have pretty weak magnets. This I have ascertained just from waving a screwdriver around within close proximity.
I also noticed the same thing with my 420A
drivers. Compared to some other speakers I have eg; Pioneer PTR9 Ribbon tweeter the magnets seem very strong.
The Altecs sound good as far as I can tell, but how do I tell if they need re-magnetization? Maybe somebody can enlighten me?

**drongo** · September 2nd, 2003, 01:03 PM

I figured that the percieved magnetic field that I guessed at being weak would be due to some extent to the shielding of the driver. Although it did appear to be fairly mild in the gap area.
What you guys sugested is appreciated and seems pretty straight forward and practicle. only thing is by the time I send them off from Australia and get them back
it will probally end up costing more than what I paid for them. Is it true, that a woofer needs to be stripped of its cone before it has its magnet re-charged? As an after thought How dose the 420A stack up against other 15 inch LF drivers like the 515? Thanks, nice talking.

**[email protected]** · September 3rd, 2003, 07:29 AM

Contact these guys.

http://www.cpcaudio.com/service/service_frames2.htm

**[email protected]** · September 3rd, 2003, 07:34 AM

These guys should be able to direct you to "local" (in-country) service.

http://www.aftermarketdiaphragms.com/info.html

**drongo** · September 4th, 2003, 03:31 AM

Good, thanks for the replies, I will follow those leads. Happy listening!

**marcuswilson** · September 23rd, 2003, 07:52 AM

What you guys sugested is appreciated and seems pretty straight forward and practicle. only thing is by the time I send them off from Australia and get them back
it will probally end up costing more than what I paid for them. Is it true, that a woofer needs to be stripped of its cone before it has its magnet re-charged?

The woofer can often be remaged with only the dustcap removed.

If you have found no-one yet try Axent Audio 25 Portage Rd, New Lynn Auckland New Zealand. They do a lot of work for me. Ph 64 9 8271220.

**Roland N R** · September 23rd, 2003, 07:56 PM

Only way to tell for sure if magnets are weak is with a Gaussmeter in the VC gap. But you may detect a loss in High freq for comp drivers and reduced MR clarity for woofers. For Altec drivers with shielded alnico magnets you can not guess at it by using the attraction to a screwdriver. How do yours sound?? If concerned compare yours to another prior to shelling out for remag fees...you may not need it.