Stromberg and Carlson behemoths

Discussion in 'Speakers' started by KingJT, Sep 11, 2017.

  1. hunter00

    hunter00 Super Member

    Messages:
    2,707
    Location:
    Mission b.c
    Sorry boys these AP-55's have never been in Boston.Purchased in B.C Canada after they were sourced down south yrs ago and wont be for sale anytime soon.Its been a fairly long build and altho they dont realy challenge my Fisher 50A's there close enough that thier long term keepers
     
  2. KingJT

    KingJT Active Member

    Messages:
    160
    Location:
    Dedham, MA
    Well I now know two of these suckers just barely fit in the back of a Rav4.
    I will thoroughly document whatever I do with them but that won't start until the weekend at the earliest.
     

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    elitopus and turnitdown like this.
  3. turnitdown

    turnitdown AK Subscriber Subscriber

    Messages:
    1,239
    Location:
    Tallahassee, FL
    This is the best thread tonight!
     
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  4. hunter00

    hunter00 Super Member

    Messages:
    2,707
    Location:
    Mission b.c
    how about a quick peek inside!
     
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  5. KingJT

    KingJT Active Member

    Messages:
    160
    Location:
    Dedham, MA
    I'll work on that tomorrow. Very curious about getting the grill off. I think there are screws coming up from underneath.
     
  6. jeb98

    jeb98 Active Member

    Messages:
    116
    Location:
    New Haven, CT
    This is exciting
     
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  7. KingJT

    KingJT Active Member

    Messages:
    160
    Location:
    Dedham, MA
    Well they work and sound better than I expected. Not exactly ideal listening environment. Hopefully I'll get the grills off Friday evening and we can see what's underneath. The cat approves.
     

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  8. GD70

    GD70 AK Subscriber Subscriber

    Messages:
    11,659
    Location:
    Northern Westchester Co, NY
    Good for you! See, they fit in the house!
    Time to make that basement a listening cave!
     
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  9. KingJT

    KingJT Active Member

    Messages:
    160
    Location:
    Dedham, MA
    We did get a great new dehumidifier this summer!
    I may hit you up for some refinishing advice soon GD. Looks like somebody did a poor job with some type of clear coat substance at some point. I'd like to sand that off and just hit it with tung oil or Danish oil as i am not a fan of the gloss.
     
  10. KingJT

    KingJT Active Member

    Messages:
    160
    Location:
    Dedham, MA
    Success!
    Grill is actually very easy to get off. Four screws on the bottom then a hole to stick a screwdriver in to pop the grill off. There are three nubs on the top of the grill to hold it in place. There is also a metal lattice behind the grill cloth to protect the speakers.
    Speakers are a 12", 7" and a tweeter.
    Paper cones with treated surrounds.
    Here are some more pictures.
    Very exciting!
     

    Attached Files:

    Ds2000 likes this.
  11. KingJT

    KingJT Active Member

    Messages:
    160
    Location:
    Dedham, MA
    Previous owner clearly spray painted the grills black which is a shame.
    Note the original color in the picture.
    I intend to get them back to a lighter color.
    Thinking these may be MSS491s.
     

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  12. damacman

    damacman Blown and Injected Subscriber

    Messages:
    6,511
    Location:
    Gilbert, AZ
    You have a very rare find there!
     
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  13. KingJT

    KingJT Active Member

    Messages:
    160
    Location:
    Dedham, MA
    Although both tweeters are definitely working, one speaker does not have the clear highs the other does. I am hoping some deoxit to the high and mid balance pots might take care of that.
    I'll give that a shot tomorrow and see if I can get a look at the crossover.
     
  14. elitopus

    elitopus Super Member

    Messages:
    2,294
    Location:
    Saint Augustine
    Maybe there is something you could wash the grill cloth in that would remove the paint, but not ruin the cloth. I'm trying to think of what would remove spray paint, that isn't a harsh solvent.

    I would think the weak HF on the one speaker is either a dirty pot like you mentioned, or a bad capacitor in the crossover. You could always swap tweeters to see if the problem follows. If the deoxit doesn't fix it that is.

    Nice find
     
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  15. KingJT

    KingJT Active Member

    Messages:
    160
    Location:
    Dedham, MA
    My thoughts exactly.
    I'm hoping a good cleaning will do the trick.
    Someone at classic speakers offered up a crossover schematic that doesn't look too crazy, but I'll try to get in there today and have a look.
     
  16. KingJT

    KingJT Active Member

    Messages:
    160
    Location:
    Dedham, MA
    So the speaker with the diminished highs had its High Freq Balance control disconnected and internally wired to a different pot.
    Turned that up and the highs returned.
    It now seems the mids in that speaker are a bit off.
    I'm a little concerned about the pots. They are covered in a white crystal powder. I've recently read about old pots being coated in cadmium and that this is highly toxic.
    Anyone have any experience or knowledge about this potential danger?
    Here are some internal pics including the pots and crossover.
    For the record I washed up thoroughly and the cabinets are sealed back up.
    Thanks.

    Mike
     

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  17. elitopus

    elitopus Super Member

    Messages:
    2,294
    Location:
    Saint Augustine
    Cadmium powder is usually a yellowish powder. I can't tell from your pics if that is what it is.

    I have run into cadmium powder on many old tube amps chassis, speaker parts, and other various audio related hardware. You are right, its bad stuff. I wipe if off with a cloth dampened with alcohol. It comes back eventually. Your best bet is replacing the cadmium coated hardware.

    If you are planning on keeping these speakers, I would consider replacing the pots with matching units, or just replacing them with fixed resistors.
     
  18. KingJT

    KingJT Active Member

    Messages:
    160
    Location:
    Dedham, MA
    There is white powdery stuff on the pots and some of the screw in connections on the crossover.
    I'm thinking my best bet is to replace the pots and whatever caps are in the crossover.
    Not sure if I'll be able to keep them just because they are so damn big.
    My concern is what is an acceptable level of refurbishing that will enhance or at the very least maintain their value.
    I kind of feel that in their current state, if I replace the four pots, recap the crossovers, sand and treat the cabs with tung oil and paint or recover the grill cloth these things will be killer but will I have adversely affected their value.
     
  19. tyella

    tyella AK Subscriber Subscriber

    Messages:
    1,180
    Location:
    Missouri
    Great find! I'm glad you went back for them. Now I can live vicariously through you.
     

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