Ideas or concerns about upgrading a pair of 9849A's

Hello,
I am new to the forum, and have obtained a pair of Altec 9849A Studio monitors.
The bass is fine, but I would like to enhance the upper end with 908-8B drivers.
Should the crossovers be rebuilt or redesigned? Do the enclosures need to be ported as in some of Altec's other models? Any thoughts on the pro's and con's of protecting these speakers with fuses? What is with the speaker wire terminals? Hard to believe there was nothing better off the shelf to equip these with in the mid 70's.
I have time off during the holidays to work with these speakers. I am building stands to get them about 18" off the floor, they sounded way too muddled close to the floor. They are currently on stands I built for Wharfedale Diamonds. ( I usually
tend to overengineer things whenever possible).
Thanks for your time, and Happy Holidays to all.

Hi Wolfenbit ! Welcome to the Altec User Board ! Are these speakers all original ? What are the HF drivers ? 902's I believe....

Hello,
As far as I can tell, the speakers are all original.The cabinets could use some TLC, they look as if they were pole mounted at one time.

I would start with the Crossovers first.They are nice little monitors ! If they have 902-8T's they should have nice HF.I think they got 414-8B's in them too.If they are 902-8T they will have loading caps in them.The recommendation on that is to remove the black loading caps and insert a piecs of 1/8" felt in the back cover.That should help in getting a smoother response.

Altec Compression Driver Rear Loading Caps

Greets!

Welcome!

New caps, yes, and since the few I?ve seen had 808-8B [Symbiotik] MI drivers, it probably will need a modded XO for later drivers.

Doesn?t hurt, but light bulbs would be my choice as you can see how much they?re being over driven.

??? They are ported. If you mean re-tuned, well, that?s a personal preference/app dependent choice. They are voiced to be wall mounted with the horn on bottom at/above ear height, so well away from any boundaries you may prefer tuning them higher or even sealing them off and using a separate sub system. For corner loading, you may want to tune them lower.

GM

HF is likely an 806A or 806-8A if you have the early sealed version.

In fact, if you have the early sealed version, much about it is quite unique and not like the later ported versions 9849-8A and 9849-8D.

Some pics would go a long way.

If you have the sealed version, some pics of the woofer and crossover would be very enlightening.

Once we see what you have, it may be possible to positively identify the components.

EDIT: apologies for the simulpost GM.

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??? They are ported.

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The early ones were sealed with a foam edged woofer and 900 hz XO.

http://www.lansingheritage.org/image...itor/page5.jpg

No need, stuff happens and I learned something as I don't recall a sealed version. The same basic info would apply though if these were voiced for mid-wall mounting also.

GM

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Originally Posted by wolfenbit

Hello,
I am new to the forum, and have obtained a pair of Altec 9849A Studio monitors.
The bass is fine, but I would like to enhance the upper end with 908-8B drivers.
Should the crossovers be rebuilt or redesigned? Do the enclosures need to be ported as in some of Altec's other models? Any thoughts on the pro's and con's of protecting these speakers with fuses? What is with the speaker wire terminals? Hard to believe there was nothing better off the shelf to equip these with in the mid 70's.
I have time off during the holidays to work with these speakers. I am building stands to get them about 18" off the floor, they sounded way too muddled close to the floor. They are currently on stands I built for Wharfedale Diamonds. ( I usually
tend to overengineer things whenever possible).
Thanks for your time, and Happy Holidays to all.

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Sorry for the delay, I had to build bookshelves for my daughter for Christmas. The speaker serial#s are 632 and 633. I am going to install the 908-8B drivers but need to verify whether they have loading caps or not. If so, how do you get them out? On the vintage Altec site, the pdf for the 9849A does not show them to be ported as the -8b's were.( That was the reason for my earlier question.) The woofers are definitely 414-b's, but the serial numbers are hard to read. Unsure what the older HF drivers are, the top end rolls off too early for me to believe they could be 902-8T's. ( I haven't a clue really.) The crossovers seem to be in good shape, but I am getting rid of the stock speaker terminals, and am going with a design to accept banana plugs. I took a few more pics which I will upload later.
Thanks for the feedback, you guys rock!!!

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Unsure what the older HF drivers are

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Look like 806-8A's to me.

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but I am getting rid of the stock speaker terminals, and am going with a design to accept banana plugs.

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Stock terminals are easily upgraded and i can think of many reasons to do so.

OTOH, banana plugs were designed for easy interchangeability of test leads on test equipment. I can't think of any good reason to use them for speaker connections. They are unreliable, and inconsistent for long term current transmission. Don't wait until one eventually vibrates out and shorts the speaker lead when you've stepped out of the room. My amplifiers all cringed watching me type this.:D

One of the best speaker connections you'll ever make is a lightly tinned bare wire firmly clamped down in a binding post. If you need something that looks fancy to impress your friends, use some gold plated spades and dress up their installation with some cable "pants" made from different colored heat shrink.

908 is Symbiotik, Altecspeak for an aluminum dome/synthetic surround. Can be identified by a brown ring around the dome.

http://i107.photobucket.com/albums/m...sympasfrnt.jpg


Image from Bowtie's photobucket


So in order...

Remove loading caps, add felt. You will need shorter screws.

Aluminum GPA frams.

Recap crossovers.

All of the above will improve HF dramatically. The only thing I could suggest beyond that is a crossover similar to the Model 19 with separate mid/high adjustments. It would raise the xover to 1200 Hz but that should not cause an issue.

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The only thing I could suggest beyond that is a crossover similar to the Model 19 with separate mid/high adjustments. It would raise the xover to 1200 Hz but that should not cause an issue.

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I agree, a mid adjustment would be sweet, but the stock XO is really a pretty good one albeit a PITA to work on as it's pretty stuffed.

His stock XO's should cross at 1500hz, they even have a bit of EQ built in to help smooth and perceivably extend the HF a bit with those 806's.

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Originally Posted by bowtie427ss

His stock XO's should cross at 1500hz, they even have a bit of EQ built in to help smooth and perceivably extend the HF a bit with those 806's.

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Scratch my last comment then, stocker prolly OK. I have only owned 900 Hz crossover versions, so was thinking of that. Recapping should be done AFTER the other mods. Might not be necessary.

Hello again,
I have written two posts, but have been mysteriously logged out both times before they went through. (Wouldn't be such a big deal if I could type worth a damn.) Anyways, the 9849A crosses over at 800hz, with a top end that extends only to 15khz, per an old Altec brochure. If they had the 902-8t's in them for hf drivers, that would take them out to 20khz, and I would leave them alone. I purchased the 908-8b's for replacements. I have not been able to get them apart to check for loading caps, I don't want to pry on them and damage them.
I understand the concern about the banana plug conversion. I would definitely expect problems if the speakers were connected and disconnected often. I have them on a pair of Wharfdale diamonds, and haven't had any issues. They are also on the Perreaux amp which will eventually be used to drive the Altecs.
If the 908-8b's require a higher crossover point, I will gladly rebuild the crossovers. And the final project will be new cabinets, I have a lot if furniture grade 3/4" plywood I scored for free from work.
It would be a shame if the final product didn't look as good as it sounds.
Thanks for your input, all feedback from the audiophile legends is appreciated.

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Anyways, the 9849A crosses over at 800hz, with a top end that extends only to 15khz, per an old Altec brochure.

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I'd double check the component values in your networks. It's possible their evolution took place in steps, possibly the 414 came along before they raised the crossover point. But, i am doubtful of this.

Can you post an internal pic of a network?

The 1975 reference guide(one of the most trusted pieces of Altec lit) says 9849A uses the 32343 network. http://www.lansingheritage.org/image...ers/page11.jpg

The 1500hz 32343/9849 network is fairly unique and fairly easy to recognize with an internal pic, also not a bad idea to inspect for broken solder joints/lugs, i've encountered more than one on this model.

It's been brought to light several times on this forum that the Altec literature is not 100% accurate, and we also have to consider that changes and revisions were ongoing, often after catalogs and brochures were printed.

One of the big advantages of the evolution into the 414 woofer would have been the 414's ability to smoothly play up to a much higher crossover point than the previous woofer in a sealed alignment. So, my logic wants to believe the 414 and 1500hz XO point came along at the same time.

Just my .02 .................

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Originally Posted by bowtie427ss

Look like 806-8A's to me.

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Yup agreed ! Since they are 8 ohm they are 806-8A's 16 ohm would be 806A. The 806-8A's I have seen all had the 23744 diaphragm in them.So they should have plenty of top end.Yes the first places to look are at the diaphragm and inside the crossovers.Also loose grounds/wiring.

I have no doubt when you track down the problem you will be happy with them.They should rock !

FWIW - Those montors look like 9849-8B's


http://altecpro.com/pdfs/vintage/Spe...r%20System.pdf

Careful AB, his internals are date coded 1974, and use "pipe and plate" alnico motors. 9849-8B uses all ferrite motors, introduced prolly sometime in 1979-80.

AFAIK, the history goes something like this:

9849A originals used a foam edge woofer, sealed box, and 900hz XO.

Sometime not long after their introduction(very early 70's) came the 414 and ports. The move to a 1500hz XO may or may not have happened at the same time.

Sometime late '74 or early '75 the 9849-8A was born with the newly designed cast return pots on both HF and LF sections.

9849-8B arrived circa 1979-80, and with it's new ferrite motors offered a big step up in sensitivity and sizzle at the cost of some midrange smoothness and warmth.

This is my .02 based on the info i've been able to glean over the years combined with owning multiple 9849's, temper it accordingly.

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Originally Posted by bowtie427ss

Careful AB, his internals are date coded 1974, and use "pipe and plate" alnico motors. 9849-8B uses all ferrite motors, introduced prolly sometime in 1979-80.

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Bowtie I'm referring to the enclosures he has there.Although it says 9849A. It looks like a 9849-8B to me,they are ported cabs.

WRT the internals it wouldn't be the first time that Altec speaker systems had other internals than what it was supposed to be ! Where are you seeing date codes on those drivers ?

In the Altec Ling or LTV era is when there was the most discrepancies IMO.The 414 is definitely in the Ling era.

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Bowtie I'm referring to the enclosures he has there.Although it says 9849A. It looks like a 9849-8B to me,they are ported cabs.

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Sure enough they do/should, all the ported cabs are essentially the same for 9849A, 8A, and 8B. It is the driver load that makes the difference.

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Where are you seeing date codes on those drivers ?

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The only date code i saw was on his crossover. The drivers are easy enough to date within a narrow range by virtue of the pipe and plate construction of the alnico motors, and black paint. By some point in '75 9849's were using the "new improved design"(think 416B and 802G) 1 piece cast magnet structures and would continue until the introduction of the ferrites in 79-80.

I have 1975 vintage 9849-8D's, their load consists of non-tangerine(later 23746 had tangerines) equipped 23746 HF drivers which have one piece cast pots, basically an 806 with the light phragm, and 414-8C woofers which use the same 1 piece cast motor pot as the 416B.

http://www.hostboard.com/forums/

http://www.hostboard.com/forums/

OK got it.I see now. I never seen the code stamped on the face of the crossover like that before and in black on black ... :confused2:

Hello,
I have uploaded some pics of the crossovers. I have not seen any obvious problems with them, hopefully you will be able to tell what they are. Most listeners would probably be content with their sound as is, I am just hoping to get a fuller top end. I do enjoy the mid range detail they have, I listened to a Hall and Oates tune called "Out of Touch", and heard a background guitar track I did not know was there. My wife did not understand why I would be interested in "old stereo stuff" like these speakers until I put her on the couch in the living room in front of them in the dark. I played REM's Everybody Hurts, and you'd swear Michael Stipe was sitting on top of the tv that was in between the Altecs. They kind of remind me of myself, somewhat old and beatup, but still with potential.
Thanks for your advice with my ongoing project.

Definitely the 32343 network. I suppose i should map out a circuit diagram one of these days so we can all figure out exactly what the extra goodies are doing to shape the HF response. besides sounding great in the 9849's i've also found them to be a worthy temporary plug n play upgrade for the stock 604-8G network.

Thanks,
And a side note for Altec's Best- My first cousin Jim Herrmann is the defensive backs coach for the Giants. I got to see him when he came to town a few weeks back for the Cowboys game here.( I live just south of Dallas.) So I too will be rooting for them, he's been with them for three seasons but is not sure if he'll be back next season.
Later

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Originally Posted by bowtie427ss

Definitely the 32343 network. I suppose i should map out a circuit diagram one of these days so we can all figure out exactly what the extra goodies are doing to shape the HF response. besides sounding great in the 9849's i've also found them to be a worthy temporary plug n play upgrade for the stock 604-8G network.

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I wonder if it's a Zobel (spelling?) network like the 1221A crossovers are......... or so I've been told they are.

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Originally Posted by wolfenbit

Thanks,
And a side note for Altec's Best- My first cousin Jim Herrmann is the defensive backs coach for the Giants. So I too will be rooting for them, he's been with them for three seasons but is not sure if he'll be back next season.
Later

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Cool ! Go Giants ! :cool2: Can't wait for that Packers-Giants game should be a good one...

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Originally Posted by bowtie427ss

Definitely the 32343 network. I suppose i should map out a circuit diagram one of these days so we can all figure out exactly what the extra goodies are doing to shape the HF response. besides sounding great in the 9849's i've also found them to be a worthy temporary plug n play upgrade for the stock 604-8G network.

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Someone reverse engineered this back on a previous post. Looks like zobels on both HF and LF with the typical 2nd order network. There is a HF bypass cap that will give a needed 6db or so boost to the top end.

I have three 9849-8D running as front channels in a home theater setup and they are pretty awesome with a modified Karlson K15 doing sub duty to fill in the bass. Some day I will recap these old crossovers just to see if improvements can be had but they seem to be working OK with the old original parts for now.

http://www.hostboard.com/forums/f700...er/index2.html

http://www.hostboard.com/forums/hbmc.../2011/04/2.png

> This is the network diagram you're referring to ( I think ) .

> The 2 most significant problems on this drawing are ;
(i) it's never been double checked by anyone else owning this network ,
(ii) all the inductor values are simply guesses .

> It would be nice if someone took their 32343 network apart / & then measured the components with something like WT2 and then corrected the above schematic .

:)

Hello,
I got the 908-8b's apart, but am unsure whether I'm looking at a loading cap or not. The picture shows the unit removed from the 908, and the 806 cap next to it. I have a few more pics, but can't remove the other pics from the upload manager to make more room. I am guessing that the cap was already removed from the driver before I bought it, the mounting screws had been replaced with shorter screws on one of the drivers. I have replaced the speaker terminals on the crossover units. One wire seemed to have heated up considerably to one of the inductors, the insulation has been melted, but nothing else seems to have been affected.
Thanks

Cap on the left is new style loading cap found on 900 series drivers, on OEM apps where the driver would be inside a cabinet they're often the only cap on the driver, there is no "cover" per se`

So it cannot be taken apart, it is one unit?

Remove the screws. Cap comes off. Fram is underneath.
Be careful.
Ron

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Originally Posted by RonSSS

Remove the screws. Cap comes off. Fram is underneath.
Be careful.
Ron

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sounds as if maybe the cap is stuck to the diaphragm mounting hub. most originally had a neoprene or similar material gasket between the hub and cap, these sometimes get a bit sticky. I would emphasize the "be careful" part.

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Originally Posted by bowtie427ss

I would emphasize the "be careful" part.

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+2 Try and use a brass or stainless or aluminum screw driver as well, once you get near those screws the magnetic field will suck a steel driver right into the Diaphragm.If you must use a steel one use your finger to wrap around the tip of the driver to prevent an accident.

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Originally Posted by Altec Best

+2 Try and use a brass or stainless or aluminum screw driver as well, once you get near those screws the magnetic field will suck a steel driver right into the Diaphragm.If you must use a steel one use your finger to wrap around the tip of the driver to prevent an accident.

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AB, if i understand him correctly, i think he has the diaphragm and cap separated from the motor already. So, there'd be no nearby field to contend with, if i'm understanding correctly.:D

By the same token, that would mean that the very delicate coil and former are exposed. I don't think we can over emphasize the careful part here for those who are new to hands on experience with these parts. Ham hands beware!

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Originally Posted by bowtie427ss

AB, if i understand him correctly, i think he has the diaphragm and cap separated from the motor already. So, there'd be no nearby field to contend with, if i'm understanding correctly.:D

By the same token, that would mean that the very delicate coil and former are exposed. I don't think we can over emphasize the careful part here for those who are new to hands on experience with these parts. Ham hands beware!

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Thanks Tom for the heads up! I assumed he was talking about taking the driver apart. Without going back to read the whole thread. :redface2:

Bad habit on my part ! Try to zip through too quickly.... :frown2: