in Search
Latest post 11-03-2011 3:53 PM by Rich. 181 replies.
Page 1 of 8 (182 items) 1 2 3 4 5 Next > ... Last »
Sort Posts: Previous Next
  • 09-18-2010 9:53 PM

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    I rescued a pair of Beovox M70s (without grills or stands) from a very nice guy who insisted on demonstrating them for me by playing the tuner section of an Altec Lansing receiver from "back in the day."  Who knew Altec Lansing once made home receivers?

    Anyway, wouldn't have been a problem, except the otherwise very nice guy was driving the Altec Lansing well into the clipping stage of its amplifier stage.  A loud "bang" would come from the right channel every 30 to 60 seconds!  I was afraid for the poor little guys.

    Here's what fifty bucks (!) will buy you in the depressed economy of Central Florida.


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 09-18-2010 9:59 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    The front and the back of the cabinet are a very rigid plastic (seems the same as what I ran into with my S40 refurb project), and the sides, top and bottom are best described as "rough wood vinyl that is restorable."

    I listened to a bit of music with them back at the house on the floor of my garage without any care to placement.  They sounded musical and ready to rock.  After verifying all the drivers were working (or rather, seemed to be working), I took them inside the house to open them up.

    The best news so far:  rubber surrounds!


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 09-18-2010 10:02 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    Rubber surrounds part 2!

    The woofer cone seems a plastic of some sort, the same feel as Infinity woofers from the 80s.  Didn't seem like the polypropylene Vifa woofers I worked with a little in the 80s and 90s.

    This phase link is a paper cone with rubber surround.

     


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 09-18-2010 10:04 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    The infamous, gigantic dome midrange.


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 09-18-2010 10:06 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    I am looking forward to taking a look under the hood of this tweeter. 

    What's the story with this grill?  Is it aesthetic?  For dispersion?  Just to protect what's behind it?


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 09-18-2010 10:08 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    If you're after the crossover, don't go through the woofer! 

    The back of an M70 comes off by removing 8 screws in the back.


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 09-18-2010 10:10 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    With the damping material removed, you can see a wooden brace, phase link subenclosure (which also serves as a brace since it butts up against the back of the cabinet), and the crossover network.


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 09-18-2010 10:12 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    A closeup of the crossover network.

    1, 2, 3, 4, 5, 6, 7, 8, 9, 10 capacitors!

     


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 09-18-2010 10:24 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    Here's the other crossover.  You can see they're different.

    The serial numbers of the two speakers are quite different as well.  Both speakers have a label that says, "HT M70 Type 6304."  But the one from above has the serial number 174020.  The one whose crossover is pictured below has the serial number 1227022.

    The only history I have for these speakers is that the nice guy I rescued them from never really used them, and he got them "from some guy out in the country."

    To my eye, the wood vinyls of the two speakers are subtly different.  This difference did not show up in any of the pictures I took, though.

    First up for these speakers will be some more listening - hooked up to the BM 2400 I think!  New caps are already ordered, and I think I'll try refinishing the cabinets for the first time.

    I am not looking forward to rebuilding these crossovers, but I'm guessing it's got to be done.


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 09-19-2010 2:34 AM In reply to

    • Dillen
    • Top 10 Contributor
    • Joined on 02-14-2007
    • Copenhagen / Denmark
    • Posts 5,008
    • Founder

    Re: Beovox M70 Rescue & Adoption

    Nice project !

    The woofer was changed in production from s/n 1442001 and the tweeter can be one of two types.
    The crossover is seen in several different versions accordingly, the capacitor kit you ordered, covers this.
    One crossover seems to have been repaired (a couple of new caps) but otherwise they look identical.

    You really should glue the magnet to the metal basket on the filler unit. It has a tendency to work lose,
    especially in transport, and then the center piece and magnet will snap to one side, sandwiching the coil
    and blocking the cone.
    A bit of 2-comp. epoxy on the magnet edge where it meets with the metal chassis will help keep it alive.

    Same problem is seen in the Beovox P45 speakers, where the woofers are of the same build as
    the M70 filler (though not with identical specs).

    Martin

  • 09-19-2010 5:11 AM In reply to

    • Craig
    • Top 10 Contributor
      Male
    • Joined on 03-29-2007
    • Costa Del St Evenage
    • Posts 4,855
    • Founder

    Re: Beovox M70 Rescue & Adoption

    Dillen:

    Nice project !

    The woofer was changed in production from s/n 1442001 and the tweeter can be one of two types.

    Wondered why they diferent from a pair I refoamed a  few years back. Had two pairs. One got refoamed and the other stripped for parts. Still got the tweeters and one of the large dome midrange units. Think the midrange were made by ITT iirc.

     

     

    CraigSmile

    For millions of years, mankind lived just like the animals. Then something happened which unleashed the power of our imagination. We learned to talk and we learned to listen..

  • 09-19-2010 6:06 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    Dillen:

    One crossover seems to have been repaired (a couple of new caps) but otherwise they look identical.

    The second posted crossover photo would be "original" then?

    I figured the first one had been messed with based on the woofer lead being spliced into the main lead.  Geeked

    Why fix something if you aren't going to do it right?

    Dillen:

    You really should glue the magnet to the metal basket on the filler unit. It has a tendency to work lose,
    especially in transport, and then the center piece and magnet will snap to one side, sandwiching the coil
    and blocking the cone.
    A bit of 2-comp. epoxy on the magnet edge where it meets with the metal chassis will help keep it alive.

    To turn an American phrase upside down:  is it easier done than said?

    Wait a minute, maybe I get it:  do I need to just remove the driver and put a bead of epoxy all the way around where they mate, as though I were caulking a bathtub?

    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 09-20-2010 4:56 PM In reply to

    • Dillen
    • Top 10 Contributor
    • Joined on 02-14-2007
    • Copenhagen / Denmark
    • Posts 5,008
    • Founder

    Re: Beovox M70 Rescue & Adoption

    I didn't notice the spliced leads and I don't have a crossover here to compare with at present but aren't the
    woofer leads going the same place electrically on both crossovers ?
    Looks as if the lead was spliced simply because it was otherwise too short, I'm sure
    you can see it better than I.

    Yes, much easier done than said and bathtub caulking sounds about right.

    Martin

  • 03-13-2011 7:31 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    Well, I had to take a break from all things B&O for awhile because I got a full-time job.  Coupled with full-time grad school and a family, I just had no spare time so I put the M70s away for awhile and stopped posting to the site.

    Winning second prize in last month's draw got the itch going again, I must say.  So I'm finished with grad school in a bit over a month, so I figured, what the heck, let's get those M70s back out.  Who cares if we don't have time.  We will sleep after school is over and let the hobby (obsession) back in!

    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 03-13-2011 7:38 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    There is ample evidence these M70s are not a "matched pair."  Just look at them.  Exhibit B.  (Exhibit A is above, serial numbers not even close to each other).

     


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 03-13-2011 7:43 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    The crossover mounts are different.  One speaker has the wood strip attached by a groove in the side, and the other is attached to a block that is in turn attached to the side.

     


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 03-13-2011 7:44 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    The rest of Exhibit C.

     


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 03-13-2011 7:53 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    Both boxes have seen better days.  The sides weren't so bad, but most of the corners had taken a blow, and both tops were very scratched.  Since the pair doesn't look like a pair, I decided this set would be my first foray into refinishing.

    I bought an orbital sander yesterday and some tinted (red oak) wood filler.  I touched them up a bit with the filler and hit them with some 60 grit with the orbital sander.

    Before:

     


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 03-13-2011 7:55 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    After hitting the speakers with the 60 grit, I hit them with some 220 grit by hand.  Bummer that in order to get the scratches completely out, I ended up sanding off all the veneer at the corners. 

    For the finish, of course the local DIY store didn't have "Rosewood," so I went with a "Red Mahogany."  I was pretty sure it would be darker than original (I'd used "Red Mahogany" before [on mahogany]), but that might be OK so as to hide remaining blemishes.

    The product I used was "Minwax Wood Finish Red Mahogany."

    After sanding, before wood finish:

     


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 03-13-2011 8:16 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    And now the cabinets sit in the garage drying.

    Meanwhile, I've bought all new Solen capacitors (9 per box!) and new resistors (10 per box!).  I've salvaged the 4 inductors from each box and will reuse them. 

    Of course I took the drivers out before refinishing the cabinets.  I'm going to check part numbers on the drivers and make sure they are the same across both sides.  Then I'm going to perform the epoxy surgery on the phase link as per Martin's direction above.

    At least one of the drivers also needs work on the connection (a woofer - a little hot glue should fix it I think).  By the way, above I wrote the woofers are some plastic - I must've been on crack that day because they're paper.

    I'm still trying to decide how to actually put the crossovers together.  Using Solens (huge) creates a real estate problem.  Below is a bread board showing all the parts.  I put this together to test different brands of capacitors before I settled on Solens.

     


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 03-13-2011 9:50 PM In reply to

    • Evan
    • Top 25 Contributor
      Male
    • Joined on 12-15-2008
    • Ohio | USA
    • Posts 2,601
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    Wow Rich, what a project!! Very cool.

    Keep it up! Yes -  thumbs up

    Evan

     

  • 03-14-2011 9:42 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    This was the worst corner before the attempted refinish - on a top no less.

     


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 03-14-2011 9:45 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    This is the same worst corner after the attempted refinish.

     


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 03-14-2011 9:50 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    Fixed worst corner doesn't look too bad, huh?  Unfortunately, the main goal of making two matching speakers did not work.  Looks like the one on the right needs an entire second coat, and the one on the right just needs a bit of spotty touch-up.  I'll do that at the very end of this project.

     


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

  • 03-14-2011 9:54 PM In reply to

    • Rich
    • Top 50 Contributor
      Male
    • Joined on 07-10-2010
    • Orlando, Florida, USA
    • Posts 1,089
    • Gold Member

    Re: Beovox M70 Rescue & Adoption

    Meanwhile, I think I've figured out what I'm going to do about the crossover network, but I'm not going to spoil the surprise.  I invested in a 2.75" hole drill for putting my favorite terminal cups into my Beovox restores.  Cut a beautiful hole.

     


    Current primary listening:  SMMC20EN -> BG4002 -> BM4000 -> Beovox M70

     

Page 1 of 8 (182 items) 1 2 3 4 5 Next > ... Last »
Need a cable? Just ask Steve at Sounds Heavenly Need a cable? Just ask Steve at Sounds Heavenly Need a cable? Just ask Steve at Sounds Heavenly
Beoworld Security Certificate

SSL