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jmiller
12-11-2013, 04:52 PM
I am new to the forums (obviously), but in light of my recent acquisition will be spending quite a bit of time here. I recently was given a pair of altec Lansing speakers which I can identify only by the look of the speaker since I have yet to locate a model number on the speaker. It appears to be a 9872-8a, although the crossovers do not appear to be original. Both woofers are in good physical condition and sound ok. The horns are both non functional. One is missing the diaphragm and loading cap, the other is complete but ohms out as an open circuit. My amateur diagnosis is that with new diaphragms they should work. I have located aftermarkets for 33$ and OEMS for $110. The HF driver that was complete was labeled as an 806. The one that was not complete was missing the metal cap with binding posts.

So on to my questions:

1. Is it worth the extra to buy the OEMS for 3x the price?
2. Is there anything I should know before installing the new diaphragms? I'm assuming they are self centering.
3. Where would the model number typically be listed on these speakers so that I can verify what I have?
4. Can I install the loading cap and diaphragm to the driver that is missing the metal cap and just attach the wiring directly to the screw terminals on the loading cap, or is the metal cap with binding posts necessary for proper operation? ( I am having trouble locating a metal cap without buying the whole driver)
5. What kind of wattage should I use to drive these. I have a pair of brand new 1987 model rca dimensia amps which put out 100 watts per channel that I had planned to use with these. Will 100 watts be enough or will I need to bridge one amp per speaker?
6. Any extra help is appreciated. I am well versed in newer home equipment, but have never delved into pro audio equipment or for that matter any equipment that is this old.


Thanks in advance,

Justin

jmiller
12-11-2013, 06:41 PM
Here are a couple pictures. Please excuse the quality as I took them from a worn out tablet. Two things that are throwing me off. 1. While the design looks like the pictures of 9872 I've seen, the cabinet depth seems deeper, and the horn design seems different. 2. I reinspected the crossovers and the hole was nicely city and rounded on the top two corners from the factory. The crossovers that are installed are larger than the originals and so the hole was trimmed out by hand on the bottom edge so that they would fit. At this point I am unsure exactly what I've got. Individual components listed below.


LF driver - 416-8z
HF driver - 806-8a
Crossover - n1209-8a
Horn - 511a



http://i254.photobucket.com/albums/hh108/pyro254750/IMG_20131211_212319_zps40db7f4b.jpg

http://i254.photobucket.com/albums/hh108/pyro254750/IMG_20131211_212330_zps2246c715.jpg

http://i254.photobucket.com/albums/hh108/pyro254750/IMG_20131211_212404_zpsfd434a4c.jpg

http://i254.photobucket.com/albums/hh108/pyro254750/IMG_20131211_212411_zpsfd002c93.jpg

jmiller
12-11-2013, 08:17 PM
Upon further research I think I've narrowed these down to a set of 846b Valencia's with crossover similar to a model 19. Crossover has two knobs, one for hf att and one for lf att, as well as two 1/4" jacks which I assume are for inputs from pa amps for the purpose of biamping. It also still has the original speaker wire push terminals which are wired to the input terminals of the crossover on the inside of the cabinet. The original owner of these speakers was a head sound guy at a theater in Berlin, so I'm guessing he snagged them from the theater and then made the crossover modification to improve the sound quality.

Earl K
12-12-2013, 05:03 AM
Hi Justin,

I'd agree with your latest assessment ( about you owning a Valencia, 846b ) .

I wouldn't waste my time on aftermarket diaphragms ( for either the 802 or 806 style body, compression drivers ) .

Those Altec 806's ( with new Altec/GPA diaphragms ) have quite limited HF capabilities ( due to the "smaller-than-normal" alnico magnet slug inside the driver ) / therefore I would toss ( both of ) those 806 drivers into the eBay pool .

( IMO ), one is much better off upgrading to the GPA version of the Altec-902-8a ( it has improved HF-UHF capabilities over all the Altec models, & will just fit into those boxes ) . Seen below ;

http://www.greatplainsaudio.com/902_8A.jpg (http://www.greatplainsaudio.com/downloads/902series.pdf)

Here's a current price . (http://www.ebay.com/itm/Altec-Lansing-GPA-802-804-806-902-909-902-8A-909-8A-NEW-/230667352520?pt=Vintage_Electronics_R2&hash=item35b4d879c8)

If you can't manage the funds for the slightly better sounding aluminum diaphragm, ( as found in Altec & GPA drivers ) then you can always bolt on a B&C de-250-8 driver ( available from Parts Express. (http://www.parts-express.com/bc-de250-8-1-polyimide-horn-driver-8-ohm-2-3-bolt--294-605) )

- The de-250 is now quite ubiquitous within the DIY community & is used in many DIY projects . It sports a polyimide (plastic ) diaphragm .

- There are now also a handful of ( B&C 250 inspired ) knock-offs that might just work-out for you, one such example is the newly released PRV D290 (http://www.parts-express.com/prv-audio-d290py-b-1-polyimide-horn-compression-driver-8-ohm-2-3-bolt--294-2833) ( which has garnered some good press lately ) .

:)

jmiller
12-12-2013, 06:51 PM
Earl,

I had been reading about the GPA 902s and was considering those. That being said I feel it will be much easier to sell the 806s if they are functional. In the interest of comparison I ordered a set of the cheap diaphragms and a set of OEMS. I'm going to install the aftermarket's first, run them for a day or two, then install the OEMS. That will allow me to compare the two, and then resell the aftermarket's, and if they don't meet my satisfaction, the drivers as well. At that point I can put the money towards 902s.

I've never heard this type of speaker so I don't really know what to expect. The only thing I have to compare too is a pair of bic dv64 towers used as fronts in my surround setup, so if the sound is as good as I've read it should be, the 806s may be more than sufficient for the time being.

Ed Kreamer
12-13-2013, 12:47 PM
Hello Justin:

the problem with aftermarkets ( in most cases ) is you never know exactly what you are getting. If you already have the OEM's I'd use them. The 846 is a pretty darn good speakker even today given the limitations of a 40 year old design. If you have the Model 19 xover the LF will get beamy, and if I remember right thst design wants to crossover much earlier than 1200Hz.. I've had good success with the 806 in the old days when I owned them, but like all compression drivers, the high end will begin to roll off at oh let's see around 5K I think. A good way to deal with this is to use the Altec 80904 EQ pad, inserted after the crossover. You can find a schematic here in the forum. I used the Altec N 801 crossover in those dark days of the almost forgotten past.
As far as amplifier power needed, a 25 watt tube amp will fill the house. (Why did I ever sell my Mac 225's?)

The 846b is a grand beast. It won't go much below 40Hz but it will give you great Imaging and phenominal depth, not to mention dynamic range. A real plus with classical music. just make certain you bolt the horns to the box securly or they will ring into next week. When I built mine the Altec contractor up here ( Bob Munger was his name) gave me some aquaplas to smear on the horns.

jmiller
12-25-2013, 07:16 PM
Well the speakers are now functional. Installed the new diaphragms and tested them out. They both sound great, however one has crisper HF Than the other. I have not had a chance to narrow down whether this is the crossover or the driver itself. I'm suspecting the crossover though. The leads have been resoldered and the solder job was pretty ugly. I doubt that is the cause but it tells me that someone was chasing a problem at some point.

Mr. Widget
12-25-2013, 07:28 PM
Well the speakers are now functional. Installed the new diaphragms and tested them out. They both sound great, however one has crisper HF Than the other.Diaphragm replacement can be pretty tricky and can dramatically affect the frequency response of the drivers. Sometimes the guide pin holes need to be slightly enlarged to allow proper centering.


Widget

jmiller
12-26-2013, 12:26 PM
Diaphragm replacement can be pretty tricky and can dramatically affect the frequency response of the drivers. Sometimes the guide pin holes need to be slightly enlarged to allow proper centering.


Widget

Is there a break in period on the diaphragms? They seem to be getting better with more run time. Also I think an electrical component in the crossover was stuck somehow. As I started increasing the volume the speaker which was weak on the high end suddenly started working and is now fine at all volume levels. I have started turning them up and suffice to say it is scary how loud they will go. I have yet to reach the point of distortion and the sound waves coming off the horns are so powerful it makes my skin crawl. Definitely a well made speaker. I'm starting to see the draw to vintage equipment.