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Thread: 904-8A speakers in the house

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    Senior Hostboard Member BillWojo's Avatar
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    904-8A speakers in the house

    Local CL add has been up for over a month for a set of Altec 934 loaded with 904-8A duplex speakers for 300 bucks.
    I called him when I first saw the add and he said that one would need a new cone. Ran all the numbers in my head and figured I'd have to much into them by the time I was done converting them to 604 type. Besides, I really don't have room for huge enclosures that these would need.
    Then I notice them at 200 bucks, still not to interested, that was yesterday. Today he was down to 125! I call him up and he tells me that he just gave the cabinets away but I can have the speakers and crossovers for 100 bucks!
    Needless to say I jumped into my truck and picked them up. It was a musician studio over in Philly and I was parked blocking other cars due to the storm yesterday. So I was in a bit of a hurry and left the crossovers there. He knows and I'll run back to grab them.
    I see that Ron has run them in 2.5ft cubed boxes with the stock cones and good diaphragms-no loading cap. Uses a sub. Now that I could do.
    So now I have another project for down the road.
    BTW, looks like the cone is separated from the front spider just under the Mantaray horn. Could that be the cause of the rubbing?

    BillWojo

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    Senior Hostboard Member Elitopus1's Avatar
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    Re: 904-8A speakers in the house

    Damn 100 bucks is a great deal for a pair of duplex! Even if you had to get them reconed.

    Post up some pics. Maybe the cone can be reglued.

    What diaphragms are in them? Symbiotik or regular aluminum?

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    Senior Hostboard Member RonSSS's Avatar
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    Re: 904-8A speakers in the house

    Sweet score!
    They are odd in that they essentially have two spiders.
    You could try re-gluing that outer one and see if it fixes the rub.
    Stock they have symbiotic diaphragms.
    I have my originals somewhere.

    I have been listening to mine recently. Not bad, but just don't compare to the M19's.

    I never checked with GPA on the cost to make them into 604's.

    Have fun playing with them!
    Enjoying Altec Speakers since 1972

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    Senior Hostboard Member BillWojo's Avatar
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    Re: 904-8A speakers in the house

    I only pulled the cap off one of them. It has the Symbiotik with the loading cap. They are pretty clean as they spent there entire life buried in a cabinet.
    I hope Ron joins us, he has had some experience using these in a small ported cabinet with subs for the low end. I'd like to get his cabinet specs.
    I'll try to get some pictures in the next few days. I'll post them at AK and put a link here. I can't believe I was so lucky to get them for that price. I just looked on Ebay and saw a pair in good shape sold for over a grand! They have been on CL for well over a month, I guess nobody knew what they were.

    BillWojo

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    Senior Hostboard Member RonSSS's Avatar
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    Re: 904-8A speakers in the house

    I actually do have my plans. I was pretty anal back in the day.
    I also have the measurements of the Thiele Small parameters that I did.
    The woofers didn't measure identically.
    I used BoxPlot for the enclosure design. They are actually closer to 3.5 cubic feet.
    I'd be happy to share all of that with you.

    Ron
    Enjoying Altec Speakers since 1972

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    Senior Hostboard Member BillWojo's Avatar
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    Re: 904-8A speakers in the house

    Hi Ron, I'd love to see your enclosure design if it's not a lot of trouble to post it. One thing I like about these is that they seem to work in a smaller box, I wish I had the room for 9 ft cubed cabinets but that's not going to happen anytime soon.
    I have two Definitive Technologies ProSub 800 powered subwoofers that can pick up the lowest portion of the music.
    I don't expect these to sound as good as my HeathKit AS101's with all the mods but if there even close with the great Altec sound I'd be happy.

    BillWojo

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    Senior Hostboard Member BillWojo's Avatar
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    Re: 904-8A speakers in the house

    Checked them with my meter today, the one with the bad cone has a bad voice coil as well. I can see where someone tried to do a repair on the leads under the front spider.
    Called Bill out at GPA, said it would be 120 bucks to recone it using the 904 cone and voice coil assembly.
    When I get a few extra bucks I'll ship it out. No good as it is.

    BillWojo

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    Senior Hostboard Member RonSSS's Avatar
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    Re: 904-8A speakers in the house

    Bummer on the VC. But still can't complain.

    Here is a photo of mine, sorry if they come out sideways........

    I'll have to photo the plans too. I don't have a scanner.

    BTW, this is 3/4" MDF and with the speakers in, I can't lift them myself.
    The port is in the rear BTW.

    Santana below for comparison.
    Attached Images Attached Images
    Last edited by RonSSS; March 17th, 2017 at 02:54 AM.
    Enjoying Altec Speakers since 1972

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    Senior Hostboard Member BillWojo's Avatar
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    Re: 904-8A speakers in the house

    I picked up the crossovers today. Pulled the cover off of one and boy do they look like a PIA to rebuild. They look similar to Model 19 crossovers in the layout but the aluminum panel is bent up on the end about 3" instead of being flat. Blocks easy access to the terminal strip. Add the mess of wires crossing over top of the terminal strips and most of the components are buried under a mass of wires.
    There are two L-pads, three transformer type inductors, an EQ pushbutton switch with no less than ten wires and one jumper attached. Plus four ceramic resistors and five capacitors. Needless to say, it's kind of busy in that box.
    I have searched for a schematic but can't find anything on the 904-8A crossover. Does anyone have one they could share?
    Thanks

    BillWojo

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    Senior Hostboard Member GM's Avatar
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    Re: 904-8A speakers in the house

    According to this, it's the same XO as for the 604-8K: Crossovers, Model 19 vs. N1201-8A

    Here, Jeff did some research and wound up with a simplified XO that he recommends for the 8H, 8K, hence fine for the 904-8A and you can delete all that extra circuitry done for studio engineers to twiddle with: Altec Lansing 604-8K

    GM
    Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

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