Old 515 needs remagging

[Rog]

Hello Altec aficionados

During the reconing of my two 515s, one suffered a drop and this moved the alnico slug and the moveable iron cap that makes the inner pole piece. I've managed to centre the two parts and once reconed (sadly, with OEM parts) I found that the efficiency much poorer than its brother. I used a 1.5v battery and measured cone deflection:- 4mm vs. 6mm.

On the assumption that the recones were identical, I determined to have the weaker one remagged and compare the result to the stay-at-home 515. Easy to say! In Australia, there are few repairers with the facility to demag/remag alnico motors. The one that bothered to respond and reckons they can do the work is 3000km away and can do the work only if the basket is removed. This suits me as the package can be smaller but prepping the motor for transport is still daunting. I plan to insert shims into the gap but that won't prevent a mechanical shock moving the magnet assembly.

I fly the 3000km a couple of times a year so propose to lodge the motor as check-in luggage and will 'request' that it is "handled like eggs".

I'd welcome any suggestions on the best way to pack the motor.

With air security tight, I wonder if a strong magnet might attract attention...?

Thanks from the other West Coast
Roj

[Old Guy]

Check regulations, strong magnets used to be banned on commercial airlines. Not sure if that's changed.

[Elitopus1]

Its been two years since I did it, but I have carried two 12" woofers in my carry-on before. They went through the xray in my backpack, and no one said anything. I even called my local airport security and asked first.

I would think just the magnet section of the 515 would be fine.

[mah]

Rog, When Plessy-ROLA ceased loudspeaker manufacture in Australia their speaker design engineer, Mike Lorantz, started his own loudspeaker manufacturing and service company(like GPA) near Melbourne.
Mike remagged my 802s and provided test certificates to show Gauss levels.

Contact him here: Lorantz Audio - Coming Soon The website is a new development. Lorantz has been around for yonks.

If he can't do the job because of commitments he should be able to steer you to someone who can, possibly in W.A..

Qantas requirement: Dangerous Goods | Qantas Scroll down to Magnetic Materials. The East-West instruction needs clarification.

[magnarc]

I seem to recall someone mentioning that Etone in Sydney can also recharge Alnico.

[Rog]

I seem to recall someone mentioning that Etone in Sydney can also recharge Alnico.

I shooda said who did and did not respond.

Sadly, Etone is the one provider that hasn't bothered to respond to a succession of emails whereas Sydney Speaker Hosp did respond with request for measurements (unfamiliar with 515 or not web connected?) and pics. Then they responded with a decent price (AUD$50). When the travel is imminent, I'll call both and extract firm understandings from both as to which can do th work fast if I give them a few days notice of my arrival. I'll be in Sydney only a week so won't have time to join a queue. I may visit both before parting with my hard earned.

I think that there are other providers or some who pass on the work to others but my googling failed to ferret-out more than two who claim to provide the service and only one who wanted to discuss it.

Do USA providers preserve original magnet polarity or just unzap and Rezap to their formula? (I do live in the Southern Hemishere so need to take that into account .

Thanks for entertaining my novice questions

Roj

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Rog, When Plessy-ROLA ceased loudspeaker manufacture in Australia their speaker design engineer, Mike Lorantz, started his own loudspeaker manufacturing and service company(like GPA) near Melbourne.
Mike remagged my 802s and provided test certificates to show Gauss levels.

Contact him here: Lorantz Audio - Coming Soon The website is a new development. Lorantz has been around for yonks.

If he can't do the job because of commitments he should be able to steer you to someone who can, possibly in W.A..

Qantas requirement: Dangerous Goods | Qantas Scroll down to Magnetic Materials. The East-West instruction needs clarification.

Thanks mah,

I've had contact with Lorantz several years ago, about what I cannot recall but remagging was probably it. I'll give them a call and see if they know of a local who can do the work.

My travel won't include Melbourne this coming trip, so if there isn't a local provider, I'll have to do the Dangerous Goods with Qantas (my preferred carrier) and opt for a Sydney provider.

My technique is a bit crude so I do like the idea of a field strength result. I will award the work to they who provide that 'finish'.

Roj.

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Its been two years since I did it, but I have carried two 12" woofers in my carry-on before. They went through the xray in my backpack, and no one said anything. I even called my local airport security and asked first.

I would think just the magnet section of the 515 would be fine.

Hello Elitopus1

These days, I think that a weight limit would be enforced for carry-on. Even if I got on with a motor I'd have to be certain it would go under the coach seat in front as even I, with my usually overweight laptop bag and other stuff, wouldn't put a smallish 11kg object in the o'head bin. A while back, the cabin staff, through their union, were making a bit of noise about safety during turbulence, and talk of enforcing carry-on weight limits ensued...but no action so far. It's a wonder that airlines haven't enforced the rules if only to better know the takeoff weight and better guess the necessary fuel load.

The "2 degrees of compass shift" rule (Qantas) might beat me, especially once remagged, unless the checked-in item is in a 'big enough' box or I devise some way of shielding the VC area. (The 515 has wonderfully little flux leakage everywhere else. Even the pot-to-front plate interface won't support a paper clip.) A shield that won't present removal problems would be necessary. A disc of mild steel spaced with a similar disc of plastic might work well enough and might obviate the need for shimming the VC gap.

You've got me thinking...

Roj.

[LowOhms]

Hello,

A thought, a suggestion to consider, that no one has yet brought up, maybe irrelevant :

I would suggest you consider to re-magnetize BOTH 515 drivers, so they will be equal to each other, and you will use them that way for decades into the future.

Three years ago, I had GPA re diaphragm my 802Ds, and re- magnetize BOTH of them, ( when I got back into ALTEC ) - and they were great.

Thanks, good luck with your 515s down under.

Low Ohms...... Jeff Medwin



( A"7" / A5 - 800s with 515B s and 802Ds, 16 ohms, DIY crossovers / GTO & FKP1 bypass caps, and m22759/11 internal wiring ).

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Hi Rog,

Suggest you TELEPHONE Etone, and do NOT just email them.

You will get a response if they pick up the phone !!

Think of Bill H. in the USA, as one example.



Jeff Medwin