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Hi,
I just installed new capacitors in one of my BV2600's because it sounded terrible (planning to do the other as well once this one works fine). I used 8.2uF 70V and a 22uF 50V since it was the only thing available in my local shop but this should work fine. I did not replace the resistor and coil.
When testing the speaker out now, the higher tones sound perfectly but the lower tones are just not hearable and a bass is just a strange sort of noise. I believe the cone (I don't know if this is the correct word for the complete black thing which produces the bass tones?) itself has a problem somewhere but it LOOKS fine and I don't really want/dare to open it up.
Any ideas what could be the problem or simple things to try out to find the problem?
Thanks for your replies in advance!
Laurent
Allright, I've measured some things, the woofer still measures 4 Ohm, and all connections and wires are also okay (around 0,5-0,7 Ohm which seems OK given the age of the wires and the not always clean surface I was measuring it on).You can feel the woofer working just a bit, and when a harder bass tone kicks in or the volume is a bit higher, the strange rattle appears although I can't find anything loose around it. I've captured it on video, maybe someone knows what causes this? (Excuse me for the terrible song, but you can hear it best with some good basses).
https://www.youtube.com/watch?v=_QP9LXUzCTY
Lee:Sounds like the voice coil is rubbing. Maybe the magnet has slipped.
And how can I check/fix that?
Have you tried another set of Speakers?
Looks like the amplifier has a Problem, not the Speaker...
Die_Bogener: Have you tried another set of Speakers? Looks like the amplifier has a Problem, not the Speaker...
Yes, I switched both speakers before the recap, probem stayed in the same speaker.
The easiest way to check is to gently push the woofer in and out using your fingers. Make sure you push it back in straight and not at an angle, If the voice coil is rubbing you will hear a scraping noise as you do it.
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Lee: The easiest way to check is to gently push the woofer in and out using your fingers. Make sure you push it back in straight and not at an angle, If the voice coil is rubbing you will hear a scraping noise as you do it.
Oh yes, there is a rubbing noise indeed! Thanks already! Now please tell me this is easy to fix
I'm afraid not, its quite a difficult job if the magnet has slipped. Have they been re-foamed recently? Perhaps the surrounds weren't put on correctly.
Cut the dust cap as in pic and check for the gap all around, if the magnet has slipped one side is totally closed and the other side totally open, If you can get an acetate strip of 0.10 mm in all around, add 1 acetate strip and check all around, the acetate strips must go in freely until the bottom (end) if there are differences in the gap, check the spider for damages or deforming, if the spider looks OK you may have to change the surrounds. If the surrounds has been changed that may be your problem.
The dust cap can be glued back with a small amount of glue all around. I use Aleene's Tacky glue
Collecting Vintage B&O is not a hobby, its a lifestyle.
No, they are still all original. Would there be any experts who can do this or is it just not worth it?
Søren Mexico: Cut the dust cap as in pic and check for the gap all around, if the magnet has slipped one side is totally closed and the other side totally open, If you can get an acetate strip of 0.10 mm in all around, add 1 acetate strip and check all around, the acetate strips must go in freely until the bottom (end) if there are differences in the gap, check the spider for damages or deforming, if the spider looks OK you may have to change the surrounds. If the surrounds has been changed that may be your problem. The dust cap can be glued back with a small amount of glue all around. I use Aleene's Tacky glue
Okay, seems worth trying since they're useless like this as well! Thanks!
Edit: Extra question, if just the magnet has slipped, can I just place it back? Sorry if it's a stupid question, this is my first audio DIY
Forgot to mention do not use the speakers until you find the failure, you may destroy the voice coil.
http://archivedforum2.beoworld.org/forums/p/4738/42890.aspx
I've opened the dustcap, and I don't think the magnet is really moved to one side. It is a bit more to one side but i don't think that's really it.
How can I get the magnet out the speaker because it seems glued or something?
And what I noticed as wel, if I push the cone forward a bit, almost all of the rattling is gone... Also, pushing it inward at a certain spot stops it, on the other side does not help so it might as well be the magnet? How can I get it out?
https://www.youtube.com/watch?v=z8YencjdFiE
If the magnet has become unglued the center would be totally to one side and the cone very difficult to move in and out. You will probably have to change the surrounds if the spider is OK, Do not try to loosen the magnet. Cut some acetate strips about 10 x 80 x 0.1 mm and try the gap, it is essential that the cone with voice coil is centered and parallel to the magnet.
Did you or someone else change the foam surrounds ?
As far as I know nobody changed the surrounds (which are rubber instead of foam I believe). It is indeed the cone which is not centered properly but the spider seems OK. The magnet is still glued so that's OK as well. There is just a bit more space on one side of the magnet but with a bit of pushing I can get a .10mm strip in at all sides. Should refoaming help?
Put 3 fingers centered on the cone push it in and out and listen for scratchy sound (speaker not connected) if yes it may be your surrounds. The strips should enter freely or with the same resistance all around, without moving or touching cone.
Yes it makes a slight scratchy noise, and it doesn't when I push it only on one specific side so it's definitely not centered anymore, I think I'll refoam it! Could just age be the reason it's not centered anymore?
Who knows what long storage will do to cones, spiders or surrounds, humidity and gravity does things to things, one never knows.
Yes, I would change the surrounds, but use the shimming process to do it, this will bring the cone and coil to center.
Will do! Thanks for your help, I will let you know once it's done if it has solved the problem!
Instead of refoaming, I thought why not just try with the original surround before throwing it away? So I removed the surround from the spider, used some hard photo paper to shim and reglued the surround to the spider frame. It was a lot better after that but still not 100% OK. I then found a spot where I just had to pull a little bit to get the sound good, so while playing some bass-heavy tracks I removed the surround again at that spot and then again glued it while listening if the sound was still OK. I kept pressure on it for some minutes while playing music so I could hear if it had moved a bit. Now it's dried and my speaker once again is sounding great! I could only hear a very slight bit of noise a couple of minutes ago on low volume. I'll see if it holds up, if not I know where the problem is, and can try to fix it better.
Thank you all for your advice and because I know you all love pics, here is one while shimming it!
Nice improvised fix! Good luck!
Just so we speak the same language, The Basket is the steel frame, The spider is a yellow paper like thingy sitting below the cone and glued to cone and basket. I have changed surrounds on some 15-20 woofers and never had problems. Probably you pulled the surround to one side or other while gluing it. If there are any noises at all, get it right or you will destroy your voice coil.
Oh, ok, thought the spider was the steel frame... English is not my native language and Google translate obviously tranlslates spider to something else
However, the sound I was hearing was caused by the dust cap which I had not yet glued properly, this is also fixed now.
Laurent1602: Oh, ok, thought the spider was the steel frame... English is not my native language and Google translate obviously tranlslates spider to something else However, the sound I was hearing was caused by the dust cap which I had not yet glued properly, this is also fixed now.
Now I like it