A 416 dilemma. What to do?

Mustang Marvin:

EVERYONE including "newbees" are welcome here. The mission of this forum is to help people learn and enjoy the hobbie of vintage Hi-Fi. There are no dumb questions.

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Originally Posted by Earl K

Brad,

I find your conclusion ( in red ) somewhat callous .

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Perhaps it is, but having plenty of experience throwing good money after bad, I consider it practical advice.

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Originally Posted by Earl K

My interpretation of all your posts here ( within this thread ) is that Pano ( or anyone in his position ) has sole ownership of the dilemma that he now finds himself in .

- ie; You seemingly imply that, "even talking about it here threatens the greater good ( such as the possible retirement of the $ 15.00 fee ) / & therefore he ( & the rest of us campaigning for a change to GPAs' process ) should clam up ".

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You read me pretty well Earl, only it's not the mere "talking about it" that I feel harms the greater good, it's the focused attack on GPA as the mia culpa, and the complete avoidance/dismissal of discussion of other possible causes that neither they nor Pano could have (practically/economically) forseen.

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Originally Posted by Earl K

I disagree ( if that is indeed your position ) , my perspective is that everyone here has some culpability when they simply parrot the message that these "old Altec drivers are all fixable over at GPA" . Clearly that message isn't correct and Pano has been misled by it .

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Now here is where I agree totally! You can search my posts till you're blue in the face, but you won't find a quote from me even remotely like that. I cringe when I read that oft-used phrase. Often it's made by some exhuberant recent customer that's thrilled to death with their restored Altecs, then parroted over and over again. However, people that make their financial decisions based on what they read in a web forum are in for some costly surprises.

Fortunately though, when they get to GPA, they do get practical advice. I know of several cases where Bill cost himself a sale by offering cheaper alternatives. Take Airboss' example just today.

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Originally Posted by Panomaniac

Know anyone down in Atlanta who can recharge? If shipping is not too far, I'd take another chance.

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Nobody anymore, but the local re-coner reminded me of some folks I know from way back that may can still do it for us DIYers, so got more emails to send.

GM

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Originally Posted by Earl K

- I guess your assumption is that GPA didn't discharge the alnico first before recharging , correct ? Maybe that didn't happen, I dunno .

- Nonetheless, there are enough testimonials ( here, within this thread ) that I would now be quite wary of sending my stuff into GPA for refurbishment .........

- It's a real drag ........I usually just take my business elsewhere to avoid the hassle.

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From the get-go, it's been my opinion that they either didn't get drained properly or just got re-zapped, but I have no experience with such big magnets or how re-coners with zapping capability actually do speakers, though it did/does seem reasonable to me that in essense there's no difference between them and the small magnets I did so many of.

I know of some others discontent with GPA that haven't seen the light of day AFAIK, so have been leery for quite awhile now, but most folks praise them, so have continued to recommend them when appropriate and hoped for the best since AFAIK there's no viable alternative ATM. Mike's situation put the brakes on me recommending them for drivers likely to need re-zapping though.

Yeah, we're of the same sentiment, life's too short to deal with any more hassle than absolutely necessary.

GM

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Originally Posted by airboss

Well, no in a word GM. You are far more the expert in this field than I am. Maybe we should talk about process control on a 900 mile pipeline sometime. Oh, never mind. No forums for that.

I can spot chicken shit and envy from mile away though. This thread, and I'm not talking about everyone, has brought out the lynch mob mentality here and I think it's time for some moderation.

Tell, me sir. Have YOU had any personally disappointing experiences with GPA or do you do all your re-mag and cone work yourself?

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Well, then it seems to me you're a glutton for punishment then. When I start getting upset with where a thread's going, I move on to more productive ones.

Actually, I may know a little about it, I designed many a custom controller for both Colonial and Canadian Pipeline during my tenure with (Eaton) Cutler-Hammer. The field trips to the various job sites weren't much fun.

Apparently not if you're using them to describe me. As a general rule, I rarely post on non-moderated forums for some of the reasons you list, but this one with a few really glaring exceptions has done quite well without it and so far, for the most part doesn't seem to need it, but there's some issues concerning GPA's customer service that needs addressing and to continue to 'sweep it under the carpet' for whatever 'fear' is to me what 'chicken shit' is all about.

No, I've never had any communication with GPA nor done any business with them, only sent some business their way and neither have I ever re-coned a driver or zapped/re-zapped a driver motor magnet. Frankly though, I don't see how either is relevant to what I've posted.

GM

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Originally Posted by bfish

Fortunately though, when they get to GPA, they do get practical advice. I know of several cases where Bill cost himself a sale by offering cheaper alternatives. Take Airboss' example just today.

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I might add, with regard to this comment that he or Chris will juke the mags, check the flux in the gap, and call before continuing. We're shooting for 11,000 but 10,400 to 10,600 is a frequently usable outcome.

Part of our discussion centered around Altec documentation. He mentioned one of the 515series that some of Altec's literature showed at somewhere far in excess of 15,000 Gauss. (I apologize, I don't recall the number) He's done exhaustive examination of the files that came with the equipment and found engineering memo's calling into question this and many other numbers. It seems perhaps, that marketing often made up their own numbers. My citation of my own post from 2003 gives salient testimony to his point. The literature often sucks.

He zapped an original set of 416B frames today and got them to just under 13,500.

Interesting point:
Altec didn't adjust the settings on the zapper for individual drivers. They built the fixture to do the ultimate zap regardless of what they put into it. They met the engineering goals by designing the magnet core to provide the proper field at full zap.

OK -

I somehow missed this thread until today.

I have just read the entire thing - now my head hurts.

Seriously, though - I think the following comments are in order:

1. Nobody's perfect, and that includes all of us. Bill has been very busy trying to keep up with orders for parts and new products, and it isn't easy when you're a small company. Couple that with the difficulties a small company can incur when an employee is sick, for example, and being shorthanded makes for a hectic day.

I know for a fact (since I handle most of GPA's email's now) that some of GPA's customers get impatient when their products aren't turned around in 24-48 hours. Bill is the most conscientious guy you'll ever meet, and, when people get impatient, he tries his best to make sure their work gets done and their products get sent out.

Unfortunately, as with all of us, it is possible that things fall through the proverbial cracks sometimes.

Now, while I am NOT accusing anyone of doing so, let me remind us all that public forums are just that - public - and I think it's best not to allow these discussions to degenerate into rock-throwing (unless it's a JBL - that's OK ;) ). One of the things that I am most proud about this Forum is that our folks, unlike some on other forums, are pretty good about policing ourselves and not falling into that trap.

2 That said, I need to find out GPA's SOP for rebuilding an woofer.

3. If it coincides with the recommendations previously made, then I will report that. If not, then I will pass the suggestions along to Bill. I'm sure that if this is an issue that has developed with some speakers (not all have this problem - in fact, most don't), then it needs to be addressed and written into the SOP.

Until then, I would recommend not throwing the baby out with the bathwater...

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Originally Posted by airboss

...Interesting point:
Altec didn't adjust the settings on the zapper for individual drivers. They built the fixture to do the ultimate zap regardless of what they put into it. They met the engineering goals by designing the magnet core to provide the proper field at full zap.

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Now where have I heard that before... oh yeah;

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Originally Posted by bfish

...For production, you don't measure 'em, you saturate 'em and go to the next one. :)

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Which is why, if the gap strength is below spec after zapping, there's something else wrong.

Thanks Todd for your post !

I think we here, all love some Altec product, and don't desire to throw the baby ( GPA ) out with the bath water .

Everything that Dan (airboss ) has just reported shows that GPA is already on track to address the concerns with process ( which I've previously mentioned ) .

<> cheers EarlK

PS : Thanks Dan for calling Bill today .

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Originally Posted by GM

#1 The field trips to the various job sites weren't much fun.

#2 Frankly though, I don't see how either is relevant to what I've posted.

GM
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The font size must mean I got your attention. Good.

As to point #1. I'm not surprised, the arctic is a cruel and demanding environment. I spent a third of my career there. In the end I wrote procedures. Some people hate the detail and the demands of methodology. I was born for it. I'm sure you've written your share.

Procedure review, or SOC as we called them at Alyeska, is a tough place to make things up as you go along. Somebody gonna getcha. I would estimate that 90% of the struggle is learning to get along.

As to point #2, Unless I'm very badly mistaken it is your assertion about draining alnico before recharge that got most of the hot air going. It is relevant in so far as a slot car motor, paramount, is not a complex acoustic driver motor. If I understood your posts, you did disassemble the motors completely before recharge. The construction of the Altec motor is not designed that way. You're an engineer; you know better.

And finally, I have no interest in kicking the shit out of anyone, but my post for a slow down in the rhetoric said NOTHING about sweeping things under the rug. It said simply, let's slow down and think about this. Let's find out what the procedure is. Let's not make it up as we go along. That's how people get hurt.

You and I would not make best friends GM, but we can be civil neighbors.

Sincerely
Dan

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Originally Posted by airboss

You and I would not make best friends GM, but we can be civil neighbors.

Sincerely
Dan

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Now don't be so sure about that!!! I'd bet you two old geezers would get along famously over a glass of Geritol or two.. Maybe swap ideas on the best way to keep the Depends secure, you know trade secrets and all :) And how about all those studly stories you both could talk about after you've popped that little blue pill, bet you could go on for hours and hours lol :)

:)

PS, although it wasn't totally on topic, I thought my magnet zapping video was pretty cool, never saw how that was done before... You'd almost think he should of worn some type of safety glove or something?

Well anyway what was this thread about ?? :D Sheez, Hi Pano,Please bring back some nice photos of the fest or the OB you are working on.Would love to see them.

I think it has more to do with this particular pair of drivers than anything else.Were talking about 1 pair of drivers out of thousands and thousands of drivers.To me this seems very rare to come across this situation were the Alnico V fails to recharge.

Unless there are others that have had this same problem.

I think the cause has more to do with material than GPA I have dealt with them (Bill and Steve) on several occasions each and have never had a problem.Oh yeah I had one problem there was 2 lock washers missing from 1 of the Large Format Driver Studs & Gaskets (Hardware Package) I had ordered.And Bill offered to send an entire new package for 2 missing Lock washers,told him not necessary.:)

We are talking about a pair of LTV drivers aren't we.

But Pano your original question was what to do. 90 some posts later question still stands.I wish I had an answer to help you my friend.But at this point I would NOT put anymore money into these drivers,there has to be an issue with the Aluminum-Nickel-Cobalt material.It is quite intriguing because they had to be OK when they were new,so what happened to these magnets. :confused: This question probably will never be answered unless you know where and how these drivers were used their entire life.

Just a little something on magnets and magnetising:

www.oersted.com/magnetizing.PDF

I would be tempted to try re-charging one speaker(the weaker one) as the paper indicates that the magnets should take re-charge.

Cheers, Marshall.

Convert them to field coils.

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Originally Posted by mah

Seeing the magnets will not recharge they were probably from a bad batch. I wonder if there are more out there from a similar build date?

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I communicated with a few knowledgeable folks recently and they all ~scoffed at this possibility.

GM

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Originally Posted by Panomaniac

Bill told me several times that he had never seen Alnico that would not recharge. Told me it was impossible to beat Alnico so badly it would not take a charge. And yet these didn't. But that's not what I've heard from some other Altec heads. Who knows?

GPA did tell me not to worry about the measurements. "Just listen to them." I did, they suck. GPA did say "they should be pretty close to spec" but would never tell me what that was. Wouldn't look it up for me. When I finally did find specs, they were obviously way out.
A frustrating experience all around.

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This has been my experience also WRT heat sinking (extreme heat build-up), cracking, chipping. Indeed, it's not uncommon for a crack or chip to increase a slot car motor's overall performance, so short of dislodging the magnet, hitting, dropping it won't necessarily adversely affect its performance. WRT heat damage, it takes >538 deg C to start changing its metallurgical structure to where it can't take a full re-charge, so are there any Altec drivers (or any brand for that matter) with VCs capable of repeatedly getting this hot in a mega-power system for a long enough time to achieve this?

I'm thinking not, but can't find any real world numbers beyond the one Tom Danley noted many years ago that >230 deg C peaks have been measured which is lower than those I've measured. According to these folks, heat affects AlNiCo's loss due to heating at a rate of 0.02%/deg C or 0.46% @ 230 deg C, so completely insignificant WRT audibly affecting a driver's Qts.
http://www.arnoldmagnetics.com/products/alnico/index.htm

Regardless, combined with having already read/heard about enough others with what I consider less than acceptable customer service from GPA, yours was the 'straw' that had me questioning their commitment to folks needing service in general and magnet re-zapping in particular.

GM

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Originally Posted by Steve Schell

I agree with Earl that the LTV era construction may have paved the way for undersized magnets.

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Wel, the magnet would have to be considerably smaller to have a > 2x higher Qes, so weighing the driver might be enlightening, though they could have increased the pot's thickness to offset it. Maybe tapping the pot to compare its ring tone to a known good driver to judge thickness?

GM

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Originally Posted by Earl K

- I still can't let go of the fact that GPA thought your pair were close enough to spec. to ship back to you ( for your listening enjoyment :confused: ) .

- The lesson I take from this is I wouldn't bother sending old beaters to GPA for recharging & then automatic reconing until GPA can confirm that the old alnico has taken a full charge( & therefore is worth reconing ) .

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Nice to know I'm not the only one that feels this way.

GM

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Originally Posted by sba2

I have a pair of JBL d130f that, like Pano?s 416s, are sitting unused because they sound like #$%^. Mine also have the higher than spec Qes values. I wonder if a remag would create any sonic miracles !

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I seriously doubt it as this can't have the correct re-cone kit in it, assuming one is still available. A good way to tell if a re-cone is 'close enough' to spec WRT the balance between Fs, Vas, Qts is to compare its measured sensitivity to published or some known good driver and allow ~ +/-10%.

GM

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Originally Posted by Earl K

- IMO, people selling woofers on eBay with aftermarket kits in them ( & not identifying this fact within the sales text ) is tantamount to fraud .

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Agreed. Where's a good lynch mob when you need one? :mad: Fraud wouldn't be a booming career choice these days if the penalties were Draconian.

GM

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Originally Posted by Earl K

That's the prevailing wisdom ( that all Alnico magnets will benefit from a recharge ).
ie ; Not just Altec woofers, but any transducer using an Alnico magnet can benefit from a recharge .

If you haven't read the complete thread , then I'd suggest that you do it sooner than later .

Ferrite magnets rarely demag .

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This is true for the various prosound apps, but not for HIFI/HT unless you're stone deaf since they will never be heated up enough to lose an audible amount of motor strength.

Yeah, for a variety of reasons I'm way out of sync, so trying to play catch-up now that I've had my memory refreshed.

Actually, it depends on the type. It seems reasonable to me that Altec and other major prosound drivers would use the hardest grades which need periodic re-zapping for peak performance and if overheated too much won't take a full charge again, so buying 'beater' ferrite prosound drivers is a crapshoot at best IMO. Again though, for HIFI/HT this is moot when using relatively H.E. low power rated drivers, though some of these mega-power band-pass sub systems loaded with super high power/Xmax rated drivers may get hot enough if a lot of movies with massive LFE are experienced at reference (or higher) SPLs.

GM

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Originally Posted by robertbartsch

Is magnet strength testing after a recharge but before a re-cone a standard practice?

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The two re-coners I used did an impedance trace to confirm Fs/relative motor strength, but don't know if it was a universal standard. In retrospect, they re-coned them after draining, charging them after assembly, but don't recall ever knowing/caring whether they checked them before though. What few I had done came back close enough to mix n' match in the same dual driver cabs, but then I requested they meet specific specs rather than just telling them to fix them.

Later on, when I'd buy new drivers the distributor measured/matched them 'close enough' and gave me a HP computer speaker program printout of the T/S specs and several suggested cab alignments, so considering the low cost of a woofer tester and how quickly drivers can be measured, I feel GPA should be providing this to ensure good quality control and customer service.

GM

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Originally Posted by Panomaniac

It is always possible that it's wrong..........

Maybe it's time to search for a near by speaker repair shop that can zap them.

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I don't see how, I mean your measured response in a 24 ft^3? cab showed it to be too small (under-damped) when it should have required significant series resistance for it to 'fill' the cab if its specs had been remotely near published.

Still working on it, apparently re-zapping AlNiCo drivers has become ~ a lost art except among manufacturers that still market products with it and a few big/long time re-coners and of course GPA.

GM

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Originally Posted by airboss

What is important, is GPA is the only supplier of the stuff this forum depends on for it's existance. Let me underline this before the fight starts; FOR THE MOST PART.

...........and a lot of opinions from a lot of folks about slot cars motors for one thing, and mostly just a lot of CONGECTURE about GPA being incompetent.

All this without some form of defence from Bill or the Captain, or Todd, who is after all the marketing director of the operation.

So, awhile back I asked, how long does alnico remain at usable strength after re-charge? No answer.

Bill H is not the devil.

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All the more reason to get stuff like this out in the open and try to figure out all the 'whys and wherefores' and how both the consumer and GPA can avoid them as much as practical in the future.

Well, until somebody proves otherwise, I consider all AlNiCo 5 magnets as one and the same WRT magnetic properties regardless of application and nowhere (so far) have I read any 'conjecture' that GPA is incompetent, only that it has some customer service and possibly some QA issues that at least a few of us believe needs addressing.

Once Bill officially closed the work order by telling Mike to "Just listen to them", how GPA handled it became open for debate same as if you'd paid to have a car repaired and it didn't perform up to spec with no explanation why.

See my earlier responses or better yet, do your own research to ensure there's no 'conjecture'.

One more time, I don't see where anyone has implied anything about Bill's lack of character or that he runs any sort of a 'sleazy' operation, just maybe a bit too casual where at least customer service is concerned, which in no way implies any incompetency. The quality of new driver construction/performance and successful driver restorations are ample proof to the contrary.

GM

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Originally Posted by Earl K

I agree ( good suggestion :) ), it would be quite helpful if Todd W. would look into what is the SOP over at GPA ( for recones in a case like Panos ) and then post that info here .

<> cheers

ps ; I think everyone knows that Bill H. is a very personable/approachable guy .

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Agreed.

I don't know it as fact, though assume it of everyone until proven otherwise, but GPA is a business and needs to be run like one, so was glad to see Todd get involved recently as I've read/heard of way too many folks being unable for whatever reason to communicate with them. Frankly, after hearing Mike's plight awhile back, I've been wondering how committed it is to the N.A. consumers and its DIYers in particular, what with so much of Altec's products now being in the Far East. Does GPA do any advertising here?

GM

I'm working on this issue, as I think I mentioned, and plan to get a complete answer out shortly.

Thanks for your patience.

Thanks Todd.

Just back from Lone Star Audio Fest in Dallas where I had a lovely pair of 605A drivers that were reconed and recharged by GPA. More on that tomorrow.

This thread has bifurcated into "what to do with them?" and "why didn't this work?"
The second is actually more interesting. Who knows how many folks actually test their drivers after rework? So we have no idea how common - or not - this problem may be.

Welcome Back Pano, Please tell me you have some pictures :) Like to hear all about the fest. :thankU: Regards ~ AB

OK - I talked with Jerry Hubbard, who was Head of Acoustic Research at Altec for over ten years, and here's what he says:

He says we first need to find out if the magnet is charged with the proper polarity. It is possible that it could have been charged in reverse. This happened, he said, at Altec all the time. There were instances when they had to go back and remagnetize entire production runs because they were charged with the wrong polarity.

The type of magnet recharger that Altec used (and Bill has) has the ability to reverse the polarity of the charge given to the magnet. When recharging an Alnico magnet, Jerry says, you set the remagnetizer one way, and you REVERSE it for Ceramic speakers. This is done because of the difference in the magnetic structures between Alnico and Ceramic. When you're done, the performance will be the same, but the procedure for getting there is different.

That said, he suggests you perform a simple test to see if the magnet is charged with the proper polarity:

1. Take the offending speaker and place it face up on a table.

2. Take a 9-volt (or 1.5-volt - whatever you have) battery, and touch the negative terminal of the battery to the negative terminal on the woofer, and the positive terminal on the battery to the positive terminal on the speaker for just an instant.

3. Observe the movement of the cone. Tell us which way it moves.

Once we know this, we can proceed.

Great info Todd. Thanks.

I tested. Both mine appeared reversed.
(positive voltage on red post = diaphragm moving toward rear of driver)

OK - Jerry said that if the cone moves away from the listener (in this case, toward the magnet), then they've been recharged with the polarity reversed and will need to be demagnetized, then recharged with the correct polarity.

With regard to remagnetization, Jerry said that any Alnico magnet that has partially lost it's charge can be successfully remagnetized without being discharged to zero first. In fact, he was adamant that discharging one while there was still some magnetism left in it was totally unnecessary.

Further, he said that if, after remagnetization, the flux density in the gap should be measured to see if it is within specification tolerances, then it should be reconed and the T/S's should be carefully measured to see if they are within spec as well.

My suggestion is to:

1. Send the woofers back to GPA.
2. Tell Bill what you've found and ask him to recharge them with the correct polarity and measure the flux density once he's done.
3. Recone them and measure the T/S's to make sure they are within specifications.
4. Include a record of the above measurements when they are returned to you.

I might add that this could have easily been a simple mistake that wasn't really anyone's fault - it just happened - and that the sooner it's cleared up, the better.

I hope this helps!

Hey Todd. Looks like we are making progress, thanks.

I'm not sure that I want to pay for another recone of these drivers plus all the shipping. =(
Having already done that. Will have to think about it. It's a chunk of change.

Let me see what I can do about that - just send them on in...

How would the proper polarity in a pair, not just one, of woofers get reversed?

If the polarity is reversed, why would another re-cone be necessary? Is this because a polarity reversal requires dis-assembly of the motor?

Is there a way to test the motor polarity before re-coning?

Thx...

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Originally Posted by Panomaniac

Hey Todd. Looks like we are making progress, thanks.

I'm not sure that I want to pay for another recone of these drivers plus all the shipping. =(
Having already done that. Will have to think about it. It's a chunk of change.

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Well having said that I think the responsibility lies on Bill's shoulders.After all you sent them in for a re-cone and remag wouldn't that be Bill's responsibility to make sure they were re-charged correctly.Bill's good people I think you will be OK Pano ;)

Yes, I'm sure we will get this all sorted out just fine. Todd has found us some very useful information. A learning experience for all!

Now I just gotta see if I still have the boxes....

They have to be un-coned, then magnetized correctly, then re-coned.

What happened at Altec, Jerry Hubbard says, is that the capacitor-based remagnification unit has the ability to be switched from polarizing the magnet one way to the other. With Ceramic, you charge it with the polarity set one way, and the reverse for Alnico.

The woofers are on their way to GPA. Should be there next week.

Gonna be very interesting to see what happens when reversing the polarity. I'm keeping my fingers crossed.

I'm wondering about the compression horn drivers. They work the other way but I think that's because the coil is turned around, not the polarity of the magnet. But they still might be re-magnetized wrong. How to tell?

Great news Michael,

I guess someone just forgot to switch the machine back around after doing some ceramics? Hope no one else has this problem.

Todd, what a slueth! I knew someone had to figure it out. It just wasn't making any sense.

Michael, you'll have your woofers again. Woohoo!