ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
I just got a pair of M75 into the door, which included broken back and PAIN.
They are heavy ! The the sound is amazing, the 3 dimensionality, the way the speaker paint up the room of a recording is unusually realistic, to my opinion
I usually find all lots of information by searching the webb, but unlucky regardging this diagram
Anyone that have the crossover diagram, I would really like to study it becfore I recap it.The treble element seems a little bit tired.
Christian
My re-capped M75 are my precious diamonds.
the user and repair manuals are available on site for silver and gold members
Collecting Vintage B&O is not a hobby, its a lifestyle.
Is there a silver and gold member function on this site ?
This is new to me
C
Christian,
as a silver member (your two silver stars) you have access to all B&O user and service manuals on Beoworld - it's a great resource.
Go to the 'main site' page and then the 'products' section. Near the bottom of the page, you should see text highlighted in blue for 'User and service manuals'. Enter there and then select your category (speakers), select 'Beovox/passive' I think it may be, and then the M75 speaker you are looking for. You then have the selection of user manual or service manual. I've just checked and it is there.
Make good use of it.
Dave.
Søren, Dave.. THANKS !
Now you are silver, look at the catalogues of the period - there is a US one with the M100 and 75 in as well as many other of B&O's best products. Hours of harmless fun!!
Peter
I too love these speakers - I think they have the best wood finish of any of the Beovox range. I have M100s which are much the same as the M75s - justv a bit bigger! I had mine re-capped and the phase link driver needed refoaming. One woofer also developed a slipped magnet which I had fixed. Splendid speakers - I use them with my Beomaster 4401.
As Peter says hours of reading to do in that section, but be careful when using schematics and part lists, there are small changes during production that do not show in the manuals, so always check your items components against schematics and/or lists. Specially in the schematics for BMs, I´ve found small differences to the actual item. Have fun
Congrats to have a 4401, Peter.
The 4401 seem to be more or less impossible to get hold of, at least in Sweden. I have enough of stiimulating workbench projects to start now at the moment, doing list of caps to buy, for my speakers, many belts ordered, and then more work with the radio in my 7700, after help from here, then learing how to adjust the turntable mechanism in 7000. Lots to look forward to
The Beovox M75 was not subject to many changes through production.
So far, all Beomaster 4401 that have surfaced have red serialnumber labels meaningthey are prorotypes.I am aware of only three BM4401 in existence, two with black fronts (as mentionedin the servicemanual so probably as they were intended for production)and one in aluminum.
Martin
have just opened the box, for a quick look at the crossover board.what a beautiful board !, all components in straights lines. Cant verify all component without removing them, not my way of work.
I will buy from the component list, and then start replacing/verifying them one by one, even if it willmean a second visit to the shop .Thought I should be a little fancy on these beauties and buy Jantzen caps.
Hmmm, guess some audiophiles would puke seing the overload section. ( hope I dont start sensitive discussion )Its so many years since I felt the smell of old electronic on my fingers.
Lots of fun.Christian
I was very fortunate - a very good friend gave it to me. It doesn't get as much use as it should but I stoked it up the other night and it performed beautifully. Still my very favourite system - I need a Beocord 2200 to go with it some time! Have my manufactured Beogram 4001 and a black 160Gb iPod at present!
Argh..there was a beocord 2200 on the swedish version of ebay the other week.
I can keep my eyes open for you, on this part of Europe if you want
Lots out there - I need to find the right one!! I'll use the 5000 if I really have to but not with my best tapes!!
Christian Christensen: Argh..there was a beocord 2200 on the swedish version of ebay the other week. I can keep my eyes open for you, on this part of Europe if you want
Are we talking about this baby?
Brengen & Ophalen
There are a couple on eBay at present. Never feel enthused enough to pull the trigger these days!!
Christian Christensen:Thought I should be a little fancy on these beauties and buy Jantzen caps.
I have tried "fancy" caps and so has Rich in more speakers, I could hear no difference to electrolytic caps, in my latest speakers I have used caps like these http://www.parts-express.com/cat/non-polarized-electrolytic-capacitors/293, these from the US, but you should be able to find similar in Sweden. Or order from Martin, I have used from him in some speakers, and they always come correctly and with instructions for installation.
If you want to use Jantzen no problem, but you may get problems with the space on the board, so check the the size before ordering.
When your speakers was produced, most bipolar caps was + - 20 %, today they are better quality and mostly within 10 % or less, so think about it before you wast your money on snake oil.
Ahhh they were 20% tolerans at that time!!!. thanks SørenThen I will deffinetly go with the ordinary cheap caps, it was partly the tolerance I was thinking of, particulary when crossover frequences are more tight on a 4 way speaker. We have a since 40 year a shop downtown Stockholm which sell speaker parts, do repaiments,aso ., the carry 14 different caps types for speaker crossover on the shelf.heading there with in a couple of hourshttp://www.hifikit.se/tillbehor/delningsfilterkomponenter/kondensatorer?page=1
Hi,
I must say I have never heard any differences between caps either.
But some people (labelled audio fools - idiophiles in French) think they make a difference. And the bigger the better.
Jacques
The reason to use polypropylene caps instead of electrolytics is they will last longer, not because they sound better.
Stick with electrolytics or you will run out of space on the M75. Trust me, I know, having recapped M70s.
Filter beforeand yes previous owner installed terminal, I wouldnt
Filter after.Yes I chose simple electrolytes.I always feel that tweeters get a bit tired by age,so I did a slight modification to the crossover.R4 that was limiting both tweeters, got an parallel equal value,4,7 Ohm, which gives a little bit more energy to themAnd I shortcut R5 which most likely function as a safety circuit, to give another dB to the highest tweeter .So from one perspective, a slight tweeks that, from my personal opinion, gives back the tweeters the energy closer to orginal when they were built with some few dBs change, but mod could easily be reversed to orginal by 4 cuts of a piece of pliers. I will listen tomorrow, it after midnight now :)
Listening result truely AMAZING !before crossoover refresh, I could hear how the filter breaking points had drifted away abit,there were holes in the frequence perspetive and slight combfilter effects.
Now after recap, details, precision,like a completly new speaker. They sound like something 2500-3000 euros downtown the audphile stores I am blown away .....................
Good job Christian, change the red Roederstein cap in the control circuit, it will give trouble sooner or later, and I think you bought a speaker from Rich, he always install new terminals in his.
Fit those caps close to the board, each in a bead of glue.Otherwise they will start rattling, vibrating and eventually break their solder joints.
For the same reason it's always a good idea to use solder with a hint of silver in it. It will notcrack as easy as the normal 60/40 so is particularly good for things that are subject tovibrations like speakers, portable radios, car stereo etc.
Thanks Søren.I checked local adds when visitng my parents in south part of SwedenBought from a guy in Göteborg, who had refoamed woofers and mids. plus adding the terminal.He has done a great job with the ringsApperance is in mint condition, not a scratch onthe side panels5 hour drive and then broken back when I carried them up. My bad back is in recovering already, it was really really worth it.
Thanks Martin, good advice, will do !
Søren Mexico: Good job Christian, change the red Roederstein cap in the control circuit, it will give trouble sooner or later, and I think you bought a speaker from Rich, he always install new terminals in his.
Glad you're happy with your result, Christian.
Soren: I've never sold a speaker I've modified, and I probably never will!