Difference Between 806 and 802 Drivers

[Earl K]

I should probably note the 806 was initially called an 804, then changed for some reason.

I suspect to avoid confusion with multicell numbers

Steve Schell addressed some of this very question in this thread over at LHF .

Tom, I have it on good authority that the Altec 804A and 806A drivers are not identical. Although they look the same externally, the 804A has a considerably smaller alnico magnet than the 806A which was its successor. The 804A was introduced during a period when management was cheapening the Altec line into oblivion; the 605A replacing the 604D was another example of their insanity. Apparently the 804A's magnet was weak enough to move the mass corner downward and begin losing the top end, prompting the introduction of the 806A after many complaints to get the h.f. response back.

Steve I'm forced to wonder about your source and his credibility. Jim Dickinson states the 804 was made from 1961 to 1964 and then rebranded as the 806 in 1964. Dickinson seems to know his Altecs.

Comparing 804 specs and 807 specs (1968 807 specs, and all seem to agree the 807 is an 806 with symbiotic) show the 804 and 807 having the same magnet weight, magnet strength and overall unit weight. This tends to confirm that the 804 and 806 are the same driver.

Perhaps your pal is confusing the 804-806 thing with the 802-806 thing.

Tom, I checked with my friend Robert. He says that despite the published specs there are indeed several differences between the 804A and 806A examples he has had apart. He says the 804A magnet has a smaller outer diameter and the phasing plug has smaller slits, giving the driver a higher compression ratio than the 806A. He also said that the diaphragm in the 804A may have a shorter voice coil than the 806A, though he is not certain about this.

I remember taking apart a junky pair of 605A Duplex drivers years ago, and was surprised to find that the h.f. driver phasing plugs had smaller slits than the 806As and 802Ds I had at the time. Robert says that the 804A and 605A share this higher compression ratio phasing plug.

Robert is in the middle of moving, but if he can find these parts he will bring them to me to photograph. Stay tuned.

Robert brought me the magnets from Altec 802D, 806A and 804A drivers. As I hope can be seen in my crummy pictures, the 802D and 806A magnets have the same inner and outer diameters but are different heights as the 802D has a longer body. The 806A magnet has the same height and inner diameter as the 804A magnet, but the larger outer diameter that it shares in common with the 802D magnet. I don't know why these relationships aren't reflected in the Altec literature of the time, but suspect that the corporate cost cutting and subsequent eating crow may have played a part.

This seems pretty definative to my eyes .

Yet to be addressed ( with pics & measurements ) is Steves'/Roberts mention of the different phase plug found in the 804/605 duplex .

Also ( some conjecture ), the reworking of the 804 into the 806 may have triggered the development and introduction of the 23744 ( lite ) diaphragm ( to help restore the HF of the 806 back to the level of the previous generations, 802 ). Just a theory, mind-you

<> EarlK

[bowtie427ss]

I know the literature makes for fairly unreliable reference, but everything i've ever seen printed about the 804, 806, and 807 states the same 13oz/.8lbs magnet weight and 13,000 gauss flux density for all of those drivers.

Now, it's obvious that those mags shown are different. So, did Altec really print this much inaccurate data over such a span of time?

[Altec Best]

Steve Schell addressed some of this very question in this thread over at LHF .




This seems pretty definative to my eyes .

Yet to be addressed ( with pics & measurements ) is Steves'/Roberts mention of the different phase plug found in the 804/605 duplex .

Also ( some conjecture ), the reworking of the 804 into the 806 may have triggered the development and introduction of the 23744 ( lite ) diaphragm ( to help restore the HF of the 806 back to the level of the previous generations, 802 ). Just a theory, mind-you

<> EarlK

Hey Earl, Actually the 23744 was developed for the 604-8G mid '70's and then found it's way into the all new 802-8G and then finally the later version of the 806-8A,B's IIRC.Then that was replaced with the 34647 with the new 902's again if recollection serves me correctly.

[Old Guy]

`

I'm willing to be of open mind on all this. By the time I was associated with Altec the 804 was long dead.

Gonna pooh-pooh the conjecture about the light fram though, there is a missing decade there.

Edit: I don't have any specs for an 804...only 804A, physical weight given for it is same as 602.

Leads me to wonder...are 804 and 804A different?

[bowtie427ss]

Stretching the topic a bit, i notice that in any of the catalogs posted on the net, the 806 is never shown or offered outside of the 1975 catalog.

Would it be safe to assume that the 806 was not offered as a raw driver, but only as an OEM in those systems that incorporated it?

Same/similar disposition for the 807?

[Old Guy]

Stretching the topic a bit, i notice that in any of the catalogs posted on the net, the 806 is never shown or offered outside of the 1975 catalog.

Would it be safe to assume that the 806 was not offered as a raw driver, but only as an OEM in those systems that incorporated it?

Same/similar disposition for the 807?

Unfortunately catalogs available are far from complete, but you may well be right re the 806...

OTOH certainly the 807 was readily available raw. I sold lots of them. Sometimes against my better judgment.

[Earl K]

The 1975 altec parts reference chart shows the 9849A using the 23744 diaphragm in the 23746 driver ( oem 806-8A ) .



The 9849A monitor is found in the following catalogue ;

Specifically, here's the page ;

The 604E is also featured in the same 1971 catalogue ;

This info suggests the existence of the 23744 diaphragm was well established before the 604-8G was released .

All other references for the 806-8A ( or 806A ) show that the 21597 ( or 20275 ) diaphragm was stock ( somewhat shooting down in flames, my previous conjecture ) .

<> EarlK

[Altec Best]

Earl I was looking in those catalogs but nowhere in the '71 does it mention the 23744 and I'm almost certain the 23744 diaphragm was first introduced in 1975.That parts list is November '75 so almost '76 and as we all know Altec literature isn't 100% accurate.The 806-8A got the 23744 late in it's production run before being phased out altogether.IIRC the lite Fram was in production from '75 to '77-'78 just a couple years.

And in '75 or around late '75 giv'er take a few months one way or the other the 806-8A (23746) 604-8G and the 802-8G all got the diaphragm (23744) and I'm almost certain but not 100% maybe 99.99 % And I think the 604-8G was the first to receive it followed by the 802 and then the (23746 / 806-8A). And I need to stress IIRC. But this will always be up for debate IME.When it comes to all original drivers of the era there are still surprises that seem to turn up all the time.I think whatever was the closest diaphragm on the table to the tech at the time is what they received.The same thing can be said for the phase plugs as well,when they were switching to Tangerines if they still had some of the metal annulars laying around they were used.There are so many variations it is impossible to keep up.I have an older pair of 23746/806-8A's with 23744 lites and the older round caps with just an ink stamp and have no other labels/stickers on them that I'm willing to bet came out of a 9849 or another closed/sealed monitor.