603 magnet strength?

Hi all:),

I am rebuilding a pair of 603 as woofers. The magnet strength on these is between 5000 to 6000 Gauss. I feel that this is low and it should be between 15000 to 17000 Gauss. Am I correct?

Regards,

Anwesh

No clue, but IME all old AlNiCo mags regardless of application need a full draining, re-magnetizing.

Generally stronger magnets are on pro and musical instrument speakers. A stronger magnet tends to increase mid band.

The 603 isn't a woofer. it's a full range speaker. With a proper cone assembly it will go lower but not a project for the uninitiated.

I’m always curious what people are using for Gauss meters. Turns out that one is a “static cum magnet meter”. You can’t make this stuff up ;)

GM-197 Static cum Electromagnet Gauss Meter - Metravi Instruments

That’s all I have to add to this thread. Thanks.

Quote:

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I feel that this is low and it should be between 15000 to 17000 Gauss. Am I correct?

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Since the motor is more or less the same motor used across 803/415/416/420, i'd expect fully charged stable strength to be quite similar in the 11,000 to 13,000 range.

One thig to note, quoted flux is measured in the gap. If you measure elsewhere you will get a different reading.

I would imagine a probe is required that fits in the gap.

I’m wondering just how many places can actually recharge speaker magnets?

A transverse probe.

Used, on evil bay a meter equipped with a thin .020" probe is 575. A little outside my hobby budget for a tool i might use twice going forward, YMMV.

Very few nowadays, I imagine! :( There use to be (3) within easy driving distance, now none nor found any in the USA listed as such, so GPA and presume Eminence will still do it unless there's no gaps in production runs to allow it anymore. :(

At the end of this video, you can see a magnetizer in action. Looks like it takes just a few seconds.

(1) This speaker has a long history || Altec Lansing 515 || DIY Completed Repairs Speaker - YouTube

Quick search, you can still buy one:

Medium Power Speaker Magnetizer-loudspeaker Magnetizer and Demagnetizer-Shengzhou Vatmag Tech Co., Ltd.-

Ron

It's de-magnetizing that is tricky, so i am told. It can take quite a few smaller zaps in reverse polarity to get to neutral in the gap.

If one doesn't remember to switch the polarity of the gausser back, your magnet will be charged backwards, effectively reversing the phase of the driver's terminals.

FWIW, near a working gausser/magnetizer is not a healthy place for humans to spend any length of time.