The LTV/smaller mag theory doesn't explain why they're signifcantly different from anything else AND each other.
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.Originally Posted by airboss
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.
"[I]We're going all the way, till the wheels fall off and burn[/I]!"
Bob Dylan, from [I]Brownsville Girl[/I]
[I]"Time wounds all heels"[/I]
John Lennon, referring to the Nixon/Hoover deportation fiasco.
The LTV/smaller mag theory doesn't explain why they're signifcantly different from anything else AND each other.
"[I]We're going all the way, till the wheels fall off and burn[/I]!"
Bob Dylan, from [I]Brownsville Girl[/I]
[I]"Time wounds all heels"[/I]
John Lennon, referring to the Nixon/Hoover deportation fiasco.
- 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 .
- 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
Bill and GPA has been very fair with me and I have used them several times.
However, I did have one slip up when I asked to have a pair of slot tweeters re-maged and recieved the cores back with the magnets no longer aligned so the noses could not be re-installed.
Anyway, I would ask Bill if the could replace the motors with new alnico.
Thanks guys. This one is a mystery to me.
The guys at GPA were very nice to me, tho they seemed a little overworked. Forgot to send the woofers back, did not supply measurements even tho they said they would both times, didn't look up specs, that sort of thing. But very willing to help and get things right, no problem. Maybe they just need a good secretary?
So anywho.... I measured the darn things again - 13th time is the charm. Here is what I found today and it matches closely with what I found last year.
416A #3325 (the weaker one)
- f(s)= 19.51 Hz
- R(e)= 6.17 Ohms
- Z(max)= 62.81 Ohms
- Q(ms)= 6.162
- Q(es)= 0.671
- Q(ts)= 0.605
- V(as)= 987 liters (34.8 cubic feet)
- L(e)= 1.00 mH
- SPL= 92.28 1W/1m
- M(ms)= 65.18 grams
- BL= 8.57
416 #32745
- f(s)= 18.84 Hz
- R(e)= 7.05 Ohms
- Z(max)= 122.90 Ohms
- Q(ms)= 6.988
- Q(es)= 0.425
- Q(ts)= 0.401
- V(as)= 942 liters (33.27 cubic feet)
- L(e)= 1.48 mH
- SPL= 93.60 1W/1m
- M(ms)= 73.22 grams
- BL= 11.99
So as my buddy John says "You've got yourself a nice set of closed box woofers there, Pano." Gee, thanks John. =(
Well Fs is nice and low, anyway. But Vas is huge and efficiency is low. Calculated BL is low, too. An Altec 416 or 515 should have a Qts down in the 0.25 range and be about 98dB/watt efficient. These are not. Qms is about right, but Qes is high = weak magnet.
I will ask about replacement magnets, for sure. Wonder if it's worth the cost? We shall see.
Yes Pano, in summation those are pretty lousy numbers .
- 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) .
- 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 ) .
- Robert, did the 077 diaphragms still fit properly into the gap or did they bind when you tried to fit them in ?
- Your problem is also quite intriguing. It sounds like either something shifted in transit or that your magnets were demagged & then remagged ( with the component parts coming loose after demagging & then being remagged while out of center ).
- You might want to contact LHF member "pelly3s" who works for an outfit ( that does recones out of "Springfield MA" ) which also owns a magnetizer .
- They might be able to fix your JBL 2405/077 drivers ( assuming the "slots" are still with you ) .
- Here's a thread to read at LHF which includes pictures of that companies magnetizer . It's possible it doesn't have enough juice to do large drivers / you'd need to ask .
<> cheers
I doubt it. Unless 416s have gone back up. It would require a second recone. The screws to remove the motor is under the spider.
Audio_by_Goodwill
Michigan, USA
Maybe we could have them Bronzed and sell them on Ebay as Rare...
Collectible Bronzed Altecs...:rotfl:
A West Virginia relative won a gold medal at the Olympics..was so proud he had it bronzed....
Your neighbors called. They like your music.
This is not meant to be a criticism of Bill, but in all my conversations I never found- 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"
him to engage like an engineer in the business of details.
"An Altec 416 or 515 should have a Qts down in the 0.25 range and be about 98dB/watt efficient. These are not. Qms is about right, but Qes is high = weak magnet."
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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