Check your local plumbers supply. See if they have anything that will match up. It'll be a start.
+1 about finding a fitting that works with the threads. If you could get something that threads in, and then find some 3 bolt flanges, you could send it all off to someone with machine shop and welding experience to put it together for you.
At least that will get the horns working until the correct adaptors are found
That's more than likely a propitiatory thread size. As a machinist I would first use a thread pitch gauge (like feeler or thickness gauges with different thread pitches on the long edge) to identify how many threads per inch. Next step is to use calipers and measure the minor diameter of the female thread. After that using a machinist handbook one can calculate a very close estimate of the outside diameter of the male thread. At that point a piece of material could be turned and single point threaded in an engine lathe to make a test piece for fit up. This was the kind of stuff I was doing at the age of sixteen. Now you need to find an old guy like me, kids today have never seen a machine shop.
Do you have a trade school near you that teaches the metal trades? Possibly talk to the teacher, maybe for a small donation they could make a project out of it. If your trade schools are anything like the ones left around here, they are always starving for operating funds. Your going to need to supply the material anyway, buy a couple of feet of the stock and leave the rest there. I'd probably use aluminum, grade 6061-T6.
BillWojo
Something like this but 2 1/2 inch. maybe: Another pair for Vitavox S2 style horn to driver adapter / fitting rings .
Maybe, contact these guys: LM
Pics of USA H805s for comparison: 2 Altec H805B horns very nice condition.for 288c | eBay
Last edited by mah; July 3rd, 2017 at 03:00 AM.
Opinion is only as valid as its verifiable supporting evidence.
Originally Posted by Steve Schell
Thanks for chiming in, Steve. I was beginning to doubt my senses when nobody else on this forum had heard of these adapters. They do seem to be rather rare though.
On another note. I read in a post of yours many years ago about a wizard in Sidney, Australia who could more or less resurrect any compression driver from the dead. I have an AGA-Baltic 1" driver that is in desperate need of a bit of magic. Do you know if this person is still active and if so, how he could be reached? This driver was connected to an early tar filled H808 horn when I bought it and I would love to hear them playing beautiful music together again, perhaps in an Iconic clone.
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As far as I can tell my horn throat is the standard Lansing 2 1/2" 16 TPI gauge.
I don't know if there is a trade school in my neck of the woods; I will have to investigate.
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The problem is that even if I could find a fitting with the correct outside threads, it's unlikely that the interior diameter
will be the right one.
Boli46, Try here for throat adapter: Vitavox Hifi - Vitavox continues to build on this illustrious history hand crafting components to power some of the world's finest loudspeaker systems.
Nothing to lose.
Some adapters: The unofficial Vitavox website- Throat Adaptors
More listed here: The unofficial Vitavox website- Catalogue Numbers, CN263, CN338, CN482 to CN488. If one of these will match your horn then a drilled flange can be fitted to the other end of the adaptor. Vitavox will make an adaptor to your specification if you wish.
Last edited by mah; July 6th, 2017 at 12:59 AM.
Opinion is only as valid as its verifiable supporting evidence.
Boli46, I will forward the thread to my friend in Sydney. Sometimes the open circuit is caused by a failure of the lead out wires and he can effect a repair. Your AGA driver is a Lansing 801 or 801b, very worthy of repair. If all else fails a more modern Altec diaphragm can be fitted.
To all, the prewar Lansing and RCA drivers used a 2.5" sixteen thread per inch coupling, referred to as the "firehose" coupling in the old days. Not sure if this was literally true. The Vitavox S2 was similar, though it used a different cutting angle on the threads, whose name has escaped me.
Hi Steve, as far as thread types i suspect either it was a buttress thread or an acme thread of some sort.
As far as the Altec horns go, I suspect a simple 60 degree form of thread.
Check on the more common audio forums (AK, DIYaudio), maybe there is a machinist/audio guy in your area that could help out. Post your story and some pics, someone may surprise you.
BillWojo
I don't need what in your Vitavox attachment is called a "throat adapter". Lansing/Altec Lansing called this a "throat" and such a "throat" is fitted to my horns. The ID of the throat is 2,5", the thread is 16 TP1, probably UNC. Vitavox used a 2,62" throat with a 16 TPI Whitworth thread. They are not compatible.
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Alas, my driver is not an 801. I wish it were. It is an AGA-Baltic alnico design with a pepper pot phase plug. The only similarity to an 801 is the half roll diaphragm surround. It is in a bad way. The voice coil is corroded fast into the magnet gap and has parted company with the diaphragm. I don't know if it can be saved or if it is worth saving.
Hi,
Here's a bit of historical reading ( in fact, a very early testimonial from the fall of 1937 ) talking about AGA Baltic testing out the new Shearer Horn system ( at the Palladium Cinema in Stockholm ) .
The article is in Swedish so one needs to use Google translate ( or similar ) .
( Click a pic ) ;
Some more reading from LHF showing an actual 1950's AGA Baltic driver ( for the above systems ) .
Fascinating stuff this ( at least to me ).
From the looks of it / AGA copied Stephens Trusonic or RCA ( more so than Lansing ) .
PS: ( here's horn info that was finally identified as an Italian maker of Cinema equipment > CINEMECCANICA )
Last edited by Earl K; July 6th, 2017 at 07:23 PM.
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