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2000th post...What have I done?

I've been a little worried about taking the distorting driver apart to clean the 'phragm. BTW, can I do this with compressed air?
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Yes compressed air(low psi 30-40 lbs at the most) can be used once the diaphragm has been removed, but it's best to only blow from the throat side back thru the driver as blowing from the diaphragm side can force debris down into the magnetic gap.

Once the rear cover is removed, be very careful around anything magnetic, keep loose screws at a distance. Touch the diaphragm itself only with your eyes, it can be very safely handled by it's mounting hub. If you see any fractures it's toast.

Before you remove a diaphragm, or disconnect the leads inside, make note of the lead wire polarity, and mark the position of the diaphragm so it goes back in exactly as it came out.

You can clean the gap with the method shown on the GPA instruction sheet.

Important note, skip steps 8 thru 13 as we're not installing a new phragm, more importantly you don't have the necessary spider shim to center the assembly if the locating pins are loosened, don't confuse those with mounting screws at disassembly time.

http://www.greatplainsaudio.com/LgDrvrDiaRepl.pdf

A couple steps i take in addition to their instructions, pre clean by running a business card or similar around the gap first to loosen anything stubborn. After using the masking tape, i like to use an alcohol prep folded over a business card or thin similar material and go all the way around the gap to remove any adhesive the tape might leave behind.

Yes those cardboard items were gaskets, and are more important than most folks think.:yes:
 
Did the measurements...

...and the throat measures 3.25" x 5"...and the widest point across the mouth of the horn is 30"...

or

B=3.25, F=5, and K=30...

1005B's for sure....:yes:

Where are these typically crossed over?:scratch2:
 
Kinda small ain't they? I thought they'd be more the size of the garage door. Good vinyl you say, I have some really sweet Twisted Sister albums. Wish I coulda been there to help.
 
Wow, now those are some very impressive speakers, I've had all my LU-1081 woofers re-coned with 515 kits, same motor. I'd be very carefuly doing much with those horn drivers, the old ones might be set-up slightly different and use shims for aligning the phase plug. Super nice score and well worth the wait, Dave. :yes: :yes: :yes:
 
Some issues...

Took a closer look at 2 of the three LF horns. All 4 woofers are indeed 515 paper surround woofers. I also found traces of tomb robbers...

Check out this picture...

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But to my disappointment, I found some damage to one of the woofers...

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A couple of small tears in the edges of the cone. Guess I'm going to be finding out whether GPA recones 515's....:sigh:

I may pull this one out when I have a chance and get a closer look. I'm guessing some of the tricks in HJS' speaker repair bag of trix may suffice for a temporary fix....:scratch2:
 

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Congratulations on 2000 posts and the aqusition of incredible speakers. Nobody at work belived me when I tried to descibe them.

Are you on good terms with your neighbours? ;-)

Dk
 
analog addict said:
Took a closer look at 2 of the three LF horns. All 4 woofers are indeed 515 paper surround woofers. I also found traces of tomb robbers...

But to my disappointment, I found some damage to one of the woofers...

A couple of small tears in the edges of the cone. Guess I'm going to be finding out whether GPA recones 515's....:sigh:

I may pull this one out when I have a chance and get a closer look. I'm guessing some of the tricks in HJS' speaker repair bag of trix may suffice for a temporary fix....:scratch2:
Click to expand...


I'm sure we can fix that right up...:smoke:
 
a little coffee filter and glue.. you'll be cooking with fire and patched right up Allan...

BTW.. nice choice of tunes.. I could only wish for a listen
 
A couple of small tears in the edges of the cone. Guess I'm going to be finding out whether GPA recones 515's....
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It's their specialty.

My advice, take some time and think about how to best proceed.

Strictly my opinion here, i'd want a quad of matching woofers.

They'd be as new when you got them back from GPA and their performance would exceed what it was as new since i "think" the recone will render them 515B's(i don't think they make the original paper surround style cones anymore).

Kinda the same thing with the HF drivers, after 60 years i suspect that the aluminum suspension has fatigued and lost some of it's tensile strength. Fresh phragms and freshly recharged magnets will give you the best possible HF.

I realize it's surely no small undertaking, but the benefits over the long term will be worth the investment.

Just some food for thought.:D
 
bowtie427ss said:
It's their specialty.

My advice, take some time and think about how to best proceed.

Strictly my opinion here, i'd want a quad of matching woofers.

They'd be as new when you got them back from GPA and their performance would exceed what it was as new since i "think" the recone will render them 515B's(i don't think they make the original paper surround style cones anymore).

Kinda the same thing with the HF drivers, after 60 years i suspect that the aluminum suspension has fatigued and lost some of it's tensile strength. Fresh phragms and freshly recharged magnets will give you the best possible HF.

I realize it's surely no small undertaking, but the benefits over the long term will be worth the investment.

Just some food for thought.:D
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Got an e-mail into Bill at GPA now. Expect a reply tomorrow....:thmbsp:

The other thing is conflicting desires on wanting these monsters to sound as good as possible versus wanting them to be maintained as they were intended to be...a time machine into the past of 60 years ago.

In some ways, I feel like owning these things is almost a responsibility AND a privilege....
 
Got an e-mail into Bill at GPA now. Expect a reply tomorrow....
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You'll probably have to call to get a response.

Todd is working on a new website for them and they're going to do something different with email so that folks get timely responses, but my understanding is that's a work in progress and won't be ready for a while yet.

I fully understand your sentiments about the preservation aspect. My thought is this, ultimately the cone material will continue to fracture and get more brittle, nothing wrong with nursing them along for a while, but the writing is on the wall for their long term wellness.

Your GPA rebuilds will be genuine "Altec" thru and thru and last you another 50-60 years. You might be able to have the original 20-24 ohm voice coils re-used if they're in good shape, i think they only wind new coils in 8 and 16 ohm versions, but please don't quote me on that, these are good questions to ask when you call.

The only real visible difference will be they'll have shiny sticky surrounds like your model 19 woofers, exactly what most folks expect to see when the Altec name is mentioned.:D
 
similost said:
a little coffee filter and glue.. you'll be cooking with fire and patched right up Allan...
Click to expand...

I like to use zig-zag rolling papers and watered down elmers for the little repairs . . .

I have a Jensen Coaxial 15 which at first glance had a few small concentric cracks like this; went to fix them with this method, but upon closer inspection, pretty much the ENTIRE circumference had tiny hairline cracks. Can you say ridden hard and put away wet :thumbsdn:. I had to coat the whole damn surround with a layer of paper and glue - original performance is out the window, and its ugly :tears:

hopefully these Altec's are not that far gone. I've done the repair on other speakers with just one or two small tears and they work fine - performance does not seem to be affected at all.

bowtie427ss probably right. .. sooner or later (especially if there are more tears not yet visible) you'll need the recone. thank the Audio Gods for GPA :yes:

On a side related note, Sixcats had an equally rare Stephens 15 incher with these Sixcats and had it reconed with a IIRC NOS Stephens cone assembly - good as new !
 
analog addict said:
I will see about finding some time in the next couple of weeks to see if the local AK'ers want to come over and have a little get together or something and check these things out...:thmbsp:

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We won't have to come over... just turn it up to eleven and we can hear them from here! :D

Scott
 
Thinking about a little listening get together...

..this Sunday afternoon. I know a fellow locally who has 3 sets of home made SET amps who can come over then. 45's, 71's and 300B's if I remember correctly. Vinyl is also a necessary requirement. I want to try these out from the 2 outside garage doors instead of 2 neighboring doors. Plus, Sunday is supposed to be the nice day, mid 70's and partly cloudy....:scratch2:....:thmbsp:

I may also try and squeeze 2 of these into the space between 2 bays in the garage. Per my measurements, they will just fit between two cars. Hopefully there will be enough space to walk between the car(s) and the speakers...:D


Now I just have to clear it with SWMBO....:nono:
 
I hope you got nice neighbors if you keep listening to them outdoors..

I think you just need to clear out the living room and stuff them in there.. use the speakers as bar tops... a few stools, you'll be set..
 
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