A 416 dilemma. What to do?

[Panomaniac]

Not to worry bfish, that's pretty much what I've done for the past year. Written them off.
But every now and again I think "maybe."

Dave - return circuit?

[bfish]

Just a tongue in cheek comment on my part, Pano. Analogous to the great satisfaction and closure I felt at a mock ceremonial burning of my ex's wedding veil after the divorce.

A return circuit failure could be a loss of good mechanical contact in the "shell" components, pole-to-plate, plate-to-pipe, and/or pipe-to-plate. The shell is steel, so cracked welds or hidden rust is a possibility. Just as a poor electrical contact adds resistance, poor mechanical contact adds reluctance.

[Panomaniac]

Oh, right. Now I see. Well could be, I suppose. They don't look that bad, but one never knows.

Can they be taken apart? Should I make field coil drivers out of them? Just hate to see any Altec gear go to waste, but it may have to.

[Tom Brennan]

Use them in an open baffle; many people that make OBs like them even though they usually sound bad.

[airboss]

Oh, right. Now I see. Well could be, I suppose. They don't look that bad, but one never knows.

Can they be taken apart? Should I make field coil drivers out of them? Just hate to see any Altec gear go to waste, but it may have to.

Let me qualify what I'm about to say with a disclaimer. I used to take speakers apart all the time when I was a kid just to play with the magnets.

Unless the entire speaker frame is made of alnico, my guess is that those magnets will come apart. They may require riveting or welding to put back together. Not difficult when you want to rescue them. It seems to me though, that to rescue an LTV altec frame by distroying an older one would not make sense UNLESS, the basket on the earlier 416/418/421 had been run over by a buss full o' hippies. I'm surprised that Bill H didn't have some sort of solution, ie refitting with new magnet assemblies.

Otherwise I'm with others that say toss them.

I've got two suitable 15" non LTV baskets and one 417-8C LTV. I've got a very early straight 417(so suffix) that is not ling.

Question: Can recones be taken off and moved to a new home, or is that glue forever?

Another option, have Weber re-cone them into a 15" guitar speaker, with aluminum dust covers. Nobody cares about Qts in an open back cab. Might make a nice Vibroverb.

[Steve Schell]

I'm afraid I am not conversant with TS parameters, so my comments here are general, not specific. AFAIK, the only real way to assess the state of charge of the magnets is to measure the flux density in the voice coil gap directly with a gauss meter. Then the readings, made at several points around the gap, can be compared to the driver spec.

I agree with Earl that the LTV era construction may have paved the way for undersized magnets. The 416 was the smaller magnet woofer to begin with, and these cheapskates had recently given the new, downspeced 804A compression driver a really tiny alnico magnet.

[GM]

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

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

[bfish]

Question: Can recones be taken off and moved to a new home, or is that glue forever?.

If you have the patience of a saint, the steady hand of a watchmaker, enjoy the buzz from MEK fumes, and nothing better to do with your time. I've done it, but I'll never do it again.

Another option, have Weber re-cone them into a 15" guitar speaker, with aluminum dust covers. Nobody cares about Qts in an open back cab. Might make a nice Vibroverb.

Now there's a good idea! Only I'd try both as-is in a sealed Dual Bassman box. No need for aluminum caps for bass guitar, and the sealed config would add some mechanical damping to compensate the weak mags.

[bfish]

The LTV/smaller mag theory doesn't explain why they're signifcantly different from anything else AND each other.

[Earl K]

The LTV/smaller mag theory doesn't explain why they're signifcantly different from anything else AND each other.

- You're right / my bad , I'm sorry / I didn't pay close enough attention to the stated differences between the Qtc of the 2 speakers ( ie ; A = .4 Qtc , B = .5 Qtc ) .

- Well, the causation of the wrong Ts numbers is still a mystery .

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.

- I gotta say, as much as anything, I'm disturbed by GPAs' attitude here ( summed up by Bills' directive of ; "just listen to them" / & then, tied to my paraphrase of ; [they're close enough, you should still like them] & yet, Pano couldn't find "the love" within this pair of GPA rehabs ) .

- So what are the lessons here ? Are they ? Don't critically measure GPAs' rehabs ( ie; look a gift horse in the mouth ) / or maybe / just don't have GPA do rehabs on ancient alnico & expect new product performance / or perhaps a reasonable conclusion would be to just buy premium ( ferrite Altec ) product from eBay that a local reconer can service ( ie; no shipping , no flakey alnico to deal with , this is my preferrence ) .
- Maybe one just needs to provide measured TS data from 3 independant sources so that the measurements are considered valid talking points with GPA .

- ( A long shot ); Perhaps Pano never liked ( or was familiar enough with ) the sound of Altec 416s and is therefore causing GPA unwarranted grief .

<> cheers