Altec 811B Horn + Big Woofer DIY System

Discussion in 'DIY' started by spwath, Jan 8, 2018.

  1. spwath

    spwath Collegiate hijinks master

    Friend
    Joined:
    Dec 13, 2015
    Likes Received:
    2,778
    Dislikes Received:
    18
    Trophy Points:
    113
    Location:
    Hartford, CT
    Doesn't appears its because of a low pass filter. Here it is with the switch turned to bi-amp, so no crossover. Unless there is still a low pass filter in the signal, this is it here:
    woofer.jpg
     
  2. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

    Friend
    Joined:
    Nov 17, 2016
    Likes Received:
    1,064
    Dislikes Received:
    7
    Trophy Points:
    93
    Location:
    San Diego
    Ok, so your woofer doesn't go high enough for your crossover point, you need to lower the crossover point to around 800Hz to help with your dip.
     
  3. spwath

    spwath Collegiate hijinks master

    Friend
    Joined:
    Dec 13, 2015
    Likes Received:
    2,778
    Dislikes Received:
    18
    Trophy Points:
    113
    Location:
    Hartford, CT
    That was my original plan, but the build in crossover was at 1.1khz and I was lazy. But this is the woofer and crossover jbl put in it...
     
    dmckean44 likes this.
  4. philipmorgan

    philipmorgan Member of the month

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    2,074
    Dislikes Received:
    1
    Trophy Points:
    93
    Location:
    Sebastopol, CA
    Home Page:
    Both woofers have that 1k dip?
     
  5. spwath

    spwath Collegiate hijinks master

    Friend
    Joined:
    Dec 13, 2015
    Likes Received:
    2,778
    Dislikes Received:
    18
    Trophy Points:
    113
    Location:
    Hartford, CT
    I only measured 1 woofer individually, but measuring each speaker individually I get a similar dip. So yup.
     
  6. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

    Friend
    Joined:
    Nov 17, 2016
    Likes Received:
    1,064
    Dislikes Received:
    7
    Trophy Points:
    93
    Location:
    San Diego
    You should probably also measure the squawker separately to make sure you can get flat to 800hz with it.
     
  7. spwath

    spwath Collegiate hijinks master

    Friend
    Joined:
    Dec 13, 2015
    Likes Received:
    2,778
    Dislikes Received:
    18
    Trophy Points:
    113
    Location:
    Hartford, CT
    Yeah, but I took out the tweeter input to put in the L-Pad, so that will be harder. But I guess ill do that eventually. It should be fine, says it can get to 500hz
     
  8. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

    Friend
    Joined:
    Nov 17, 2016
    Likes Received:
    1,064
    Dislikes Received:
    7
    Trophy Points:
    93
    Location:
    San Diego
    Last edited: Jun 9, 2018
  9. spwath

    spwath Collegiate hijinks master

    Friend
    Joined:
    Dec 13, 2015
    Likes Received:
    2,778
    Dislikes Received:
    18
    Trophy Points:
    113
    Location:
    Hartford, CT
    Looks like ill be Bi-Amping. Im getting a JLH Hood 1969 amp from ray for the highs, and a Myryad MA-120 amp and Carver CT-7 amp from some guy on craigslist in a trade for my PA amp, JBL E-140 woofer, and the JBL compression drivers. Good deal for me I think.
    Now I Just need to get a minidsp.
     
    dmckean44 and LetMeBeFrank like this.
  10. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

    Friend
    Joined:
    Nov 17, 2016
    Likes Received:
    1,064
    Dislikes Received:
    7
    Trophy Points:
    93
    Location:
    San Diego
    Did ray install bypass caps in the JHL amp for you?
     
  11. spwath

    spwath Collegiate hijinks master

    Friend
    Joined:
    Dec 13, 2015
    Likes Received:
    2,778
    Dislikes Received:
    18
    Trophy Points:
    113
    Location:
    Hartford, CT
    I don't think so, he said it was brand new. I can do that, what do they do?
     
  12. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

    Friend
    Joined:
    Nov 17, 2016
    Likes Received:
    1,064
    Dislikes Received:
    7
    Trophy Points:
    93
    Location:
    San Diego
    Just to bypass the output caps, there's a back in forth between Marv and @philipmorgan in the JLH thread on page 2 tell you how to do it.
     
  13. spwath

    spwath Collegiate hijinks master

    Friend
    Joined:
    Dec 13, 2015
    Likes Received:
    2,778
    Dislikes Received:
    18
    Trophy Points:
    113
    Location:
    Hartford, CT
    Ok, ill do that.

    For now, I now have my new pre amp and amp. 60w/channel, this will drive the lows. Then I have the jlh at 10w/channel for the highs.
    This preamp is nice too. It has a motorized volume knob, that is always fun.
    Pretty sure I got a nice deal. I gave the guy a PA amp, compression drivers, and a JBL E-140 woofer, worth no more than $450 total, he gave me these two things, sell for about $300 each on ebay.
    Unfortunatly the cool looking handles on the carver seem to be missing, but oh well.
    [​IMG]
     
  14. spwath

    spwath Collegiate hijinks master

    Friend
    Joined:
    Dec 13, 2015
    Likes Received:
    2,778
    Dislikes Received:
    18
    Trophy Points:
    113
    Location:
    Hartford, CT
    So since I got something new and shiny, I figured the best idea would be to rip it open.

    Anyone know anything about amp topology? Can I tell if this is class A, A/B, ect?
    Seems pretty empty in there, but that torroidial transformer is nice and beefy. Interesting the board says MI-120 integrated amplifier. It appears this is exactly the same board, and probably case, as the integrated amp version, just without the pre amp section.
    So, look good in there? Anyone know what topology it is?
    [​IMG] [​IMG]
     
    Thad E Ginathom and LetMeBeFrank like this.
  15. dBel84

    dBel84 Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    801
    Dislikes Received:
    1
    Trophy Points:
    93
    Myryad made some good sounding gear in the 90s, AB would be most likely

    .. dB
     
    spwath likes this.
  16. spwath

    spwath Collegiate hijinks master

    Friend
    Joined:
    Dec 13, 2015
    Likes Received:
    2,778
    Dislikes Received:
    18
    Trophy Points:
    113
    Location:
    Hartford, CT
    Thanks. I have never heard of Myryad, and did not find a ton of information about them online. But I figured I would go for it as I was just trading away a bunch of junk I didn't need, and getting an amp and a preamp.
     
  17. dBel84

    dBel84 Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    801
    Dislikes Received:
    1
    Trophy Points:
    93
    There will be a fair amount in the British audio world where they established themselves as 90s audiophile icons. (look for HiFiNewsandReviews, What Hifi... Along with Cyrus and similar brands. I have not heard their newer gear but auditioned them back in the day.

    The manual and service manual are on hifi engine
    https://www.hifiengine.com/manual_library/myryad/ma-120.shtml

    And they have a history on their home page
    http://www.myryad.co.uk/who-are-we.html

    I think you did very well out of this exchange
    .. dB
     
  18. spwath

    spwath Collegiate hijinks master

    Friend
    Joined:
    Dec 13, 2015
    Likes Received:
    2,778
    Dislikes Received:
    18
    Trophy Points:
    113
    Location:
    Hartford, CT
    Minidsp coming from @MrTie tomorrow, then I'll have some fun with that. But first, I must buy supplies for making a cable. Speaker has 4 conductor speakon for bi amping, so I'll make a cable for that into 2 pairs of banana plugs. Should be a nice and clean setup, with nice locking connector on the speaker. In the meantime, I'll work on cleaning up my setup so I can actually sit and listen there.
     
    philipmorgan and LetMeBeFrank like this.
  19. spwath

    spwath Collegiate hijinks master

    Friend
    Joined:
    Dec 13, 2015
    Likes Received:
    2,778
    Dislikes Received:
    18
    Trophy Points:
    113
    Location:
    Hartford, CT
    Hmm, something is wrong. I hooked up everything for biamping with minidsp, set the minidsp to crossover at 800hz. I turn on tweeter amp first, try playing something, hear nothing. As soon as I turn on woofer amp, a loud pop comes out of the woofers. No music. Any thoughts of what could be the problem?
    Setup is
    PC-->Dac-->Pre amp-->minidsp-->amp1/amp2
     
  20. spwath

    spwath Collegiate hijinks master

    Friend
    Joined:
    Dec 13, 2015
    Likes Received:
    2,778
    Dislikes Received:
    18
    Trophy Points:
    113
    Location:
    Hartford, CT
    Ok, the no sound was because the pre amp was on the wrong input... not sure what that pop was from the woofers though

    EDIT: Pre amp on right input, still no sound... not sure why
     
    Last edited: Jun 21, 2018

Share This Page