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Braun 910s - Das Gut Eines

Discussion in 'Speakers' started by AmCan, Mar 5, 2012.

  1. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    I decided to start my own thread here on my German Braun 910s. Braun speakers, as I am told, originated in Germany and then later sold their line to ADS. So there is an ADS Braun 910 & a German Braun 910 - "The Good Ones"! I traded for these speakers without knowing much about them and actually thought I was getting the ADS speakers until I saw them. Luckily for me I went through with the trade. My intention from the beginning was to find a speaker DIY project and these need work. The cabinets need refinishing, which is fun manly stuff. Plus I am going to recap the crossovers with no technical support manual, just the help of the good folks here at AK. I have recapped my preamp and amp already so this will be my first speaker project.

    Here are the speakers on the day I got them home. At the risk of offending Braun owners everywhere I must say I find these grills very obtrusive and they hurt my eyes to look at. It would be impossible to listen to music and look at these grills all the time so they need to come off. The hint of the cone color behind the metal fencing is beckoning to me to have a look. How could one own these speakers and expect to never have a gander at the cones?

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  2. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    Braun L-910 German Version Specs

    These are the specs on this speaker translated from a German Website using Google translator. In 1969 these speakers sold for 1500DM, which is about $1000.00 US. Calculated for inflation the cost of this speakers in 2010 would be $6200.00.

    Country: Germany
    Manufacturer / Brand: Braun, Frankfurt
    Year: 1968-1972 Type: Loudspeaker (speaker or headphone)
    Wave bands - Without
    Details
    Power type and voltage No power needed
    Loudspeaker 5 Loudspeakers
    Power out
    from Radiomuseum.org Model: Hi-Fi speaker unit L910 - Braun, Frankfurt
    Material Wooden case
    Shape Miscellaneous shapes - Described under notes.
    Dimensions (WHD) 420 x 850 x 330 mm / 16.5 x 33.5 x 13 inches
    Notes Brown Hi-Fi speaker unit L910.
    Loudspeakers: A 12-inch subwoofer, three 3-inch midrange systems
    and a 1 inch tweeter system (spherical membrane).
    Impedance of 8 ohms. Power 60 W according to DIN.
    Transition frequencies of the built-in switch 300 and 3000 Hz
    Frequency response 20 - 25000 Hz to DIN 45500.
    Finish: Wood with walnut,
    Front anodised, perforated aluminum sheet.
    Upon request, pedestal LF80 (DM 200, -) with cast aluminum arms for pivoting the speaker unit.
    Net weight (2.2 lb = 1 kg) 30 kg / 66 lb 1.3 oz (66 079 lb)
    Price in first year of sale 1500 DM
    Source of data Manual VDRG 1968 /
    Mentioned in Manual VDRG 1969 (also in 1970 and 1971)
    Literature / Schematics (1) Hi-5 Yearbook, published by G. Braun, Karlsruhe 1970
     
    Last edited: Mar 5, 2012
  3. leguerrier

    leguerrier Active Member

    Messages:
    117
    Location:
    B.C lowermainland
    I know what you mean by the speaker cover matereial ie perforated aluminum panel".ive got the same on my big Braun L-1000 studio monitors.These speakers weigh in at 130lbs each,you would of thought they would have tryed to cut wieght somehow.Mine have 13 drivers per cabinet ,my best sounding speaker and thats with AR9 in the house as well.
     
  4. Michael-Otto

    Michael-Otto Well-Known Member

    Messages:
    524
    Location:
    Germany/Freiburg
    The exchange rate $ - DM was beginning 1969 1:4,0 end 1969 1: 3,68!

    Michael-Otto
     
  5. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    Yikes! I admit I picked a 1989 exchange rate, which may have been the last year of the DM, so my figure is not exactly correct. So a 1:4 ratio or heaven sakes a 1:368 exchange rate would put the inflated value of these speakers through the roof. Without trying to do any more math, which I am very bad at unless I am reading the value off of a capacitor, we can say that these were not cheap or cheaply made speakers. I will post pics of the cones later today.
     
  6. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    There is no doubt that the German Braun are sleeper speakers in terms of quality and construction. I am still over the moon that I was offered this trade without ever even having heard of these speakers, as compared to always hearing about other more well know brands. The 910s are 66lbs but for their size they are solid, which you will see when I post pics of the inside of the box. Please feel free to post a pic of the 1000 Studio Monitor, I'd love to see the pic. Did you ever get your grills off?
     

     

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  7. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    How do I post pictures inside the text box as opposed to as attachments? I can't find the instructions on that.
     
  8. leguerrier

    leguerrier Active Member

    Messages:
    117
    Location:
    B.C lowermainland
    hey amcam,Im challenged by the pic posting proceedure here,but if you google "Braun L-1000 studio monitor system" you will get sites comeing up with pics some needing translation.i posted picks some time ago when i had them briefly for sale,may be able to find those.
     
  9. michaelhigh

    michaelhigh mind's eye music

    Messages:
    6,122
    Location:
    Lenzburg, IL
    I would run to get Brauns, on the strength of A/D/S! I would stare at pink polkadotted froo froo to hear them. I would...you get the picture...
     
  10. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    Braun L-910 Speaker Cones

    It took me no less then 5 hours to get the first grill and back cabinet door off. Luckily the second speaker grill came off more easily, only one hour but I still have one more door to go. The speaker grills were both stapled and glued, with what appears to be roofer’s silicone, into place. The door was only glued. I guess the manufacturer never intended to have them removed? Possiblly done by previous owner but that doesn't explain the staples. In order to get the grills off I used a syringe to inject a mild silicone solvent, Dow Corning 200 fluid and 244 fluid, into the grooves and then continually tried to pry and pull them off without damaging the veneer. I used a thin spatula to dig the silicone out as it would loosen from the solvent. At first I thought they were suppose to come off but couldn’t so I was trying to be careful. Later I noticed the staples coming out. I know these grills are supposed to be acoustically transparent but I am not entirely sure that would be accurate if it were to be measured. I am not sorry they are gone. The soft dome caps on the cones look awesome and you can see they used a nice paper & fiber cone for the 12in woofer. The midrange cones are very smooth and almost look laminated or like they have an acrylic wash to them. The 3.25in midrange cones are directional, which explains the horn-like sound they produce. I couldn’t have lived with the amount of dust on there that has been accumulating since the 70s. [I am allergic to dust mites.] Now I will make my own speaker grills for these and add that on to the project. Perhaps I have ruined some of the original value but to me I am going to enjoy the speakers a lot more being able to stare at the soft dome caps on the woofers like 2 large round things [areolas come to mind :D ]
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  11. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    Thanks. :thmbsp: This has been bothering me for awhile.
     
    Last edited: Mar 5, 2012

     

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  12. adam-ads

    adam-ads Super Member

    Messages:
    1,934
    Location:
    south of Boston, MA
    Nice looking speakers. Although they're very different from the ADS 910, they do seem to have the same holes on the sides for mounting on stands.

    BTW, when adding pictures, it's not necessary to submit the post and then re-edit. You can copy in the links from the attachment page before you make the initial submission.
     
  13. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    Yes they use the same stands and I would love to get my hands on a pair. When I was offered the speakers in trade I researched the ADS 910s thinking those were what he was trading. I drove an hour to get them and when I first looked at them I accused the nicest guy of intentionally deceiving me, until I saw the serial numbers. Thank god for the internet because he showed me that there was a difference between Braun and ADS. After listening to them my instincts were to take them. These speakers are going to soar after a recap. I did find an original pair of ADS 810 stands for now.
     
  14. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    Inside Cabinets

    Taking off the door was just as hard as taking off the grill. More goop! Again I used silicone solvent and a spatula and razor blade to dig this stuff out of the groves until the door would pry open. If there is one thing for certain the German’s know how to make a good box! I have attached some pictures of the back of the drivers. The tweeter says 1973 on it, which is close to the end of production date for this speaker. The crossovers are just hanging there suspended in air. I will end up building a platform to support the capacitors. The crossovers currently use ERO caps from Germany. Since there is so much space I am going to use all film caps in here! I am also going to get rid of the lamp chord. Next I am going to diagram this crossover network so as to get a better idea for how the crossover network is laid out and what I need to order.

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  15. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    Capacitor Values

    I have written the capacitor values over this image but I do not know how to draw a proper schematic. If someone is able to draw a schematic and wants to attach it I would appreciate it but I am not sure how much more useful it would be.

    Some of the Film Caps I want to use are quite large. I am anticipating needing to change some of these wires and this is where I need some advice please. What kind of wire should I use here, does it matter what gauge it is or what length I need to use between each capacitor. I was thinking that just some 14 or 16 guage Romex would work real well for bending and staying in place? I plan on using some really large Mundorf MKPs for the woofer and I don't suspect I can maintain the configuration of the crossovers as they currently appear. I am going to put in a shelf right underneath to support the large film caps but I will need to increase the wire length between the capacitors to do it. What do I need to consider if I were to do something like this or is a change in wire length like that a nominal change?

    Also I would like to change the lamp chord to a passive biwire cable. I am currently using Audioquest type 4 speaker cable and I would like to put it inside the box. I would attack the 2 positive wires to the current positive feed into the crossover network but I want to then split it into 2 5-way binding posts so I can passively biwire the speakers at the terminals. Is this o.k. to do or is it not that simple? Do I need to maintain the 2 terminal configuration or can I change it as specified above.

    Lastly, I have selected Russian K75-10 for the midrange drivers and tweeter with FT3 teflon bypass caps. I have a 4.7uf K75 and K4 bypass cap for the for the bass woofer as well. However, what would be some good resistors to replace the 2 resistors (3R3 & 1R0) in this circuit.

    All input is welcome.

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  16. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    Crossover network #2

    Once again thanks to the guys over at DIYAudio I know what to do with the wire here but I did manage to get the second cabinet opened and it is interesting to see that there appear to be some differences. One of these speakers must have had some repair made but all the capacitors are German. Considering that there are some sort of film caps in the first set of crossovers I am willing to bet that they are not original caps. Even still there are more discrepancies then just there. There is a 16.5uf vs 13.6uf on one crossover and a 40uf vs a 48uf difference on another. I kept hearing a slight bit of static in one speaker that was intermittent and this pair of caps might be the reason why. One of these looks dried out to me - either that or there is soldering resin all over it?

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  17. audiomagnate

    audiomagnate Addicted Member

    Messages:
    6,574
    Location:
    Atlanta
    It looks like they trying to match the dispersion of the tweeter with that mid array. I was expecting something more ADS like under there. Very interesting.
     
  18. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    Yes this is a completely different beast then the ADS L-910. Any idea how to reconcile the difference between crossover values for speakers 1 & 2? Speaker 1 has 13.6uf & 48uf and speaker 2 has 16.5uf & 40uf. The other 2 values are consistent with 4.7uf for the tweeter and 80-83uf for the woofer. Its the mid values that seem to vary significantly. The best I can guess to do is to just make them the same. Since I bought 4.7uf bypass caps for each crossover, to simplify things I was just going to go with 4.7uf, 14.7uf, 44.7uf, and 82.7uf (combination of 4.7+10+68uf).
     
  19. RPMz

    RPMz Active Member

    Messages:
    441
    Location:
    Ontario
    Good job. So, how do they sound, whats your impression on them? I'm always interested in hearing listeners thoughts of BraUn speakers.
     
  20. AmCan

    AmCan Active Member

    Messages:
    196
    Location:
    Toronto, Canada
    I have not finished the recap yet - in fact I have barely made any progress since this last post because my preamp broke down and I have spent months to no avail trying to fix it. I finally brought it in for repair last week so hopefully I can turn my attention to these speakers now but with warm weather here I am not hopefully but you never know. I will post back when there is something to show.

    Thanks for asking
     

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