Demagnetising

[magnarc]

Hi John

AFAIK if yours are ferrites(8Cs) then they should hold charge no problem.

If Alnico(8Bs), then maybe they have lost some of their charge, but since you haven't driven them hard, probably not.

Easiest way is to compare with a newly charged unit.

Anthony

[SOOTSHE]

Hi John

AFAIK if yours are ferrites(8Cs) then they should hold charge no problem.

If Alnico(8Bs), then maybe they have lost some of their charge, but since you haven't driven them hard, probably not.

Easiest way is to compare with a newly charged unit.

Anthony

Hi Anthony,
Yes, they are 8B's....so Alnico. Does driving them hard make them lose their charge?
Where do you get another new 8B to compare to??????

[magnarc]

Hi John

Alnico can exhibit decreased magnetic charge if they are pushed hard for extended periods of time.

I'd doubt yours would have been subject to high power levels, we're talking extended usage in say a cinema environment when the A7 is too small, or in PA/Rock situations at pubs.

None of my 8Bs are newly recharged, in fact they need charging, so I can't lend you one. By the sounds of things, your M19s are well and truly keeping up with the La Scala so maybe they are fine??

CPC Productions out at Ipswich - Murray Keidge, he may have one you could compare with, or may be able to measure the gauss/charge of the magnet.

Cheers
Anthony

[SOOTSHE]

Anthony,

I would say that the bottom end on the 19's, after the recap, is superior to the LS now. More tuneful & more accurate...& certainly plenty of oomph.
From this I would say that they are OK.

It's really handy to have another set of speakers to compare against.

[Altec Best]

Does driving them hard make them lose their charge?

Not in a home environment unless extremely hard for very long periods,I posed this very question to Bill at GPA a couple years back I thought my woofers were in need of re-charge 416-8B's as you are doing now.Mine were built Feb, '77 and he said my woofers in my model 19's if they were in a home environment for their entire life, they should never need re-charging.He said drivers in sound reinforcement-PA in clubs and venues were they are on tour so to speak are the drivers that typically need re-charging.I said but the woofers sound weak and he said to check the bypass cap in the X-over the 21 uF cap so that's when I rebuilt them.You know the rest

I would say that the bottom end on the 19's, after the recap, is superior to the LS now. More tuneful & more accurate...& certainly plenty of oomph.
From this I would say that they are OK.

Now this is the same exact result I had with mine. My Cornwall II's bass sounded deeper,louder,tighter after the 19 crossover rebuild not anymore "Complete Transformation" If you haven't heard a model 19 in quite sometime you got to hear one with the X-over upgrade,ground lug bypass, completely different pair of speakers performance wise. John if they have lost anything it will be minimal providing your details are accurate that they haven't been driven to extremes.Bill told me that I couldn't drive them hard enough,he said you wouldn't be able to sit in the room (Too Loud)and would turn the volume down way before they lost their magnetism.Now he could have made some money by me sending them in to recone,charge magnet etc.. :2thumbsup: But shouldn't need it. But if I insisted he would do it.

[SOOTSHE]

Not in a home environment unless extremely hard for very long periods,I posed this very question to Bill at GPA a couple years back I thought my woofers were in need of re-charge 416-8B's as you are doing now.Mine were built Feb, '77 and he said my woofers in my model 19's if they were in a home environment for their entire life, they should never need re-charging.He said drivers in sound reinforcement-PA in clubs and venues were they are on tour so to speak are the drivers that typically need re-charging.I said but the woofers sound weak and he said to check the bypass cap in the X-over the 21 uF cap so that's when I rebuilt them.You know the rest

Now this is the same exact result I had with mine. My Cornwall II's bass sounded deeper,louder,tighter after the 19 crossover rebuild not anymore "Complete Transformation" If you haven't heard a model 19 in quite sometime you got to hear one with the X-over upgrade,ground lug bypass, completely different pair of speakers performance wise. John if they have lost anything it will be minimal providing your details are accurate that they haven't been driven to extremes.Bill told me that I couldn't drive them hard enough,he said you wouldn't be able to sit in the room (Too Loud)and would turn the volume down way before they lost their magnetism.Now he could have made some money by me sending them in to recone,charge magnet etc.. :2thumbsup: But shouldn't need it. But if I insisted he would do it.

No, they have had a pretty easy life. I might only run it up for maybe a minute or two at the most, just to hear that awesome crack....but these days it gets too loud for me. One of the best aspects of these speakers is that I can listen at fairly low levels & still get that big sound with all of the nuances still able to be heard.

From all the comments here & the sound that I'm getting, I'm sure they don't need zapping.