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Altec 1233

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Clay_cullen

New Member
Please be kind to this newbie. I just acquired a set of Altec 1233 PA speakers. I am trying to refurb and use them for PA, not hifi speakers. The XO are in very bad shape. Does anyone have a schematic for the 1233 XO? If not, can you recommend someone who can rebuild them? I would like to lower the XO point while I am rebuilding them to 800HZ as opposed to the stock 1200HZ. At least that's what I have been told. Any help will be greatly appreciated.
 
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IF they still have the 811's they came with you really don't want to go much below 1200 cps.
you can try 16 Ohm Diaphragms, Radians are my Fav, and using the 8 ohm 1200 cps x-overs,
does actually lower the X-over point to around 1,000 give or take.
No need to rebuild the x-overs, Just upgrade the Caps . Unless you want to get better ones like the Model 19's.
 
Thank you for the reply. I still have to rebuild the XO since both of them have broken leads on the caps as well as some missing components the best I can tell by looking at pictures of other 1233 XO's. I would love to find a schematic for the XO so I could order new parts and return it to original.
 
What woofers are in them? and why are you looking to lower the XO point?
especially if not for home use.
808 horn drivers?
 
That's a really good question. I just opened them up and this is what I found, no labels. I have no clue what driver these are. Any idea?
upload_2021-10-26_23-34-13.jpegupload_2021-10-26_23-34-40.jpeg
 
It's hard to tell. Maybe Bowtie427 can tell from the #'s. But If you can take the covers off, and take a look at the diaphragms, that might at least
give a clue as how they should sound/Act 802's and 808's have the same motors. even before you take them off an Ohmeter can tell their impedance.
pretty sure they came as 8 ohms
The 1233 Xovers are pretty simple I know there are better ones here are my pair.
Mine don't even have an L-pad to turn down the horn
I thought about using Them in my model 19 resto but they are not so good for the 19’s
And my tube amp rigs
 

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Here's a look at the phragm. Of course, it has two broken leads. Everything I touch on this project is bad. Based on the number on the cover, 34075, it is an 808-8b. Does that sound right? Do you recommend Radian or GPA replacements?
upload_2021-10-27_0-10-51.jpegupload_2021-10-27_0-11-10.jpeg
 
Yep 808's with the Simbiotic phragms I love the Radians,
They sound better and are pretty bullitproof, as well as they sound great.
cheaper than the Great plains. For my tubes I like 16 ohms, but for SS
probably better off with the 8 Ohm ones.
 
I Would be curious as to the Condition of the Woofers, seeing that the other components need an overhaul.
 
808 driver with the Symbiotic diaphragm rated at 30 watts down to 500 HZ, but would take much more crossed at 1200 HZ. Te HF started rolling off around 9000 HZ and died around 13 to 14 KHZ. You want the new Diaphragms from Great Plains Audio. But then I would want to use 800 HZ crossovers for the most dynamics but 1200 HZ crossovers for the best sound providing you have the correct woofers. I would use a pair od Altec 414C 16 ohm woofers wired in parallel and bi-amp. You sjhpu;d have about 150watts available on the bottom and 50 to 60 for peaks for the horn. Remember the horn is 5 to 8 db more effiicent than woofers depending on what type of woofer box you use. Horn Loaded, Reflex or ported.
 
Yeah, the woofers are non-existant. I had one 421 already and I just found another on Ebay. It will be here tomorrow. I just need to order the phragms and figure out the XO. I really would love to see a schematic so I could order new parts and rebuild them.
 
bowtie427ss Nyjblbob Is there any chance you might have a parts list for the Altec 1233 crossover? I am trying to source the caps and resistor, but I can't get any of the numbers to match what's available from Parts Express. I guess I will need to rebuild them myself which I feel like I can if I can just find the right parts.
Thanks guys for all your help.
Clayton
 
If you go to the Link Bowtie sent and double click on the images then open them on your computer you can read all the VALUES. If PE doesn't have the exact values, you can put 2 together in parallel to get the correct #'s you can use higher Voltage caps 400-500v is fine
The poly's are relatively inexpensive
you really just have to change the Caps. The coils don't change, and I doubt the sand resister will change much either
 
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