plaskin 0 Posted October 14, 2014 Posted October 14, 2014 Anyone have an "easy" fix for a ribbon rattle? It isn't all the time, mainly on very high frequency and only one speaker. I recall seeing something about using a (don't laugh) hair dryer to heat the ribbon to stop the rattle. Alternatively, .... new ribbons I suppose. Argh!
Gene C 1,748 Posted October 15, 2014 Posted October 15, 2014 Sounds like you have the infamous ribbon buzz. Getting them repaired "if your going to spend the cash" is the only way, not aware of any drop in replacements.
hewlew1 258 Posted October 15, 2014 Posted October 15, 2014 Some times tightening the screws on the back of the ribbon will help .Not the screws holding the ribbons into the baffle but the two rows of screws that are closest to the center of the ribbon.See if you can isolate the area which has the buzz and then tighten the 6 screws that are in that area one row above one row below and the row in the center of the area that is buzzing. This is important only turn the 6 screws 1/8th turn maximum this is important only 1/8 turn see if this helps the buzz. I did it to my own and it did help. Should you try this you do so at your own risk. Also dont laugh I have heard about the hair dryer as well. 2
PMAT 2,038 Posted October 15, 2014 Posted October 15, 2014 The dryer trick apparently works. It should be after you try other things. Examine the area between the magnets and the ribbons with a flashlight. Look for debris. Sometimes the foam that covered the ribbon shed chunks that can lodge in the gap and cause problems. Be very careful with removal and remember those magnets are powerful and can suck metal into the ribbon and damage it. Often the buzz isn't the ribbon. It's just that you hear about it all the time so you just assume. Harvesting from other speakers is a good option as well. I see pairs for 4-500 and you get 2. Of course they could have problems so check them out carefully. Good luck. 1
Gene C 1,748 Posted October 15, 2014 Posted October 15, 2014 Often the buzz isn't the ribbon. It's just that you hear about it all the time so you just assume. Unfortunately in this case he already described the symptom... "It isn't all the time, mainly on very high frequency and only one speaker." Ran into the same problem on my Amazing Silvers I owned for a brief period of time. The Kapton was loose in a 2 to 3 inch area IIRC, which caused the buzz or resonance sound at certain frequencies. Remember Robert R mentioning turning the screws to tighten the magnets holding the Kapton, but also ran the risk of cracking the magnets which would destroy the ribbon assembly. I hope you are able to fix yours, had a small glimmer of hope for mine until reality set in. 1
Ratamahatta 437 Posted October 15, 2014 Posted October 15, 2014 If you really want to spend a bunch of money you can get these http://www.parts-express.com/bohlender-graebener-rd48-planar-transducer--264-704 They developed the original ribbons for the Carver speakers. There is a guy who re-builds them as well, I am sure someone has his contact info. here is one, http://www.carveraudio.com/?page_id=97
srinath 34 Posted October 15, 2014 Posted October 15, 2014 I've dismantled a ribbon and I am pretty certain it has a few design flaws. 1. Magnets are glued in. And held in with repel force from the ones across the ribbon. But the adjacent ones are in attract. IMHO, we can improve on it in atleast that respect. Weld a square steel strip to the plate with threaded holes in it. Then drill holes in another strip to match it and countersink the holes on the side that faces the ribbon. Then use drilled neo magnets and mount em all the right way. That will prevent it from moving when you bump it and stuff. 2. No shielding from external metallic dust. Get too close to it with a staple in your hand and whoosh ... The drilled holes will allow you to put a muslin like cloth to keep it from doing that. Not a 100% ideal but better than the thing now. 3. We need to make a ribon (and there are guys on diyaudio that do em - though I am not sure how they would match up to the original) and we're good. Cool. Srinath.
RobertR 847 Posted October 15, 2014 Posted October 15, 2014 Despite the claims of Parts Express, the Bolander-Graebner ribbons are NOT a drop-in replacement for the Carver type. They simply don't sound the same, period. Get on James Sauter's list for rebuilding - the voicing of the rebuilts is that of the Bob Carver factory ribbons, and the reliability is actually better than new, several longevity tricks having been learned over the years. As to scratch-building your own, anybody's free to give it a try - you would learn a great deal, no doubt. RobertR 1
Ratamahatta 437 Posted October 15, 2014 Posted October 15, 2014 I cleaned up some vintage Infinity Emit ribbon tweeters and you had to make a jig for them to come apart with or you could damage the ribbon, I cant imagine taking apart some of these.
plaskin 0 Posted October 16, 2014 Author Posted October 16, 2014 Thank you everyone! That was quick. I will try tightening and see if that helps. Didn't think about looking for foam debris. I'll do that too. I also found checked out the CarverAudio site. That will be my possible solution if the suggestions don't work. First step is to make sure I have non-ferrous screwdrivers. Right now, the AL-III's are playing some Dylan and I don't hear the buzz. Of course I'm in the other room or maybe Dylan's buzz is canceling out the speakers. Hmm.... that might be a short term fix. Listen from another room and only play Dylan. These speakers are my 2nd pair of Carvers AL III. I bought them used and I thought they were fine until I started playing some classical piano pieces. My originals, which I use in our HT setup are AL-III+ are doing fine. The two sets of speakers do sound different. The +'s are cleaner in the low end. Not sure if that means the III's are in need of a cross-over tweak or not. Of course, the amp and preamps are different between the two systems and the rooms are completely different.
plaskin 0 Posted October 16, 2014 Author Posted October 16, 2014 You are gonna lose some fingers! Great! Another hobby that wants my fingers.
Ratamahatta 437 Posted October 16, 2014 Posted October 16, 2014 You are gonna lose some fingers! Great! Another hobby that wants my fingers. That's right, if you are going to be doing anything mechanical then you might as well cut or bang your finger right from the get go to satisfy the mechanical gods, lol.
RobertR 847 Posted October 16, 2014 Posted October 16, 2014 The two sets of speakers do sound different. The +'s are cleaner in the low end. Not sure if that means the III's are in need of a cross-over tweak or not. Of course, the amp and preamps are different between the two systems and the rooms are completely different. Different rooms = different problems, particularly in the bass. You'd have to reverse the speaker locations to investigate. Also, where is your bass control set on the "non-plus" pair? In tightening the ribbons, don't turn the screws much. When you see the metal frame start to indent around the screw head a bit, that's time to stop! Hope it works for you, but don't count on it. RobertR
srinath 34 Posted October 16, 2014 Posted October 16, 2014 You are gonna lose some fingers! Great! Another hobby that wants my fingers. That's right, if you are going to be doing anything mechanical then you might as well cut or bang your finger right from the get go to satisfy the mechanical gods, lol. You wont lose a finger ... a finger nail maybe. The magnets are in repel position, they literally come apart as you unscrew. They are hard to put back - same reason - repel, but you can do it with longer bolts and 2X4's and zipties to help you. Cool. Srinath.
mbskeam 1,975 Posted October 16, 2014 Posted October 16, 2014 I used a blow dryer on a set of mine to shrink the kapton tighter, this stopped the buzz I had. but use caution as you dont want to melt the ribbon. on my main set I think poped one side of the kapton as it buzzes real bad.... [](*,)] will try the dryer first, but this sound is not really a buzz in one spot, more of a high pitch buzzing sound from the whole length of a 30"ribbon have new 60" to replace them but have to redo my xovers......crap Im sure loud music had nothing do do with this. :---
plaskin 0 Posted October 17, 2014 Author Posted October 17, 2014 mbskeam - which side do you blow dry? The front (after the foam covering is removed) or the back?
srinath 34 Posted October 18, 2014 Posted October 18, 2014 The ribbons look like this when taken apart. Cool. Srinath. 2
PMAT 2,038 Posted October 18, 2014 Posted October 18, 2014 That is very cool! Thanks for the peek inside. Were you able to repair those?
BobSmi57 25 Posted October 18, 2014 Posted October 18, 2014 I used a blow dryer on a set of mine to shrink the kapton tighter, this stopped the buzz I had.but use caution as you dont want to melt the ribbon. on my main set I think poped one side of the kapton as it buzzes real bad.... will try the dryer first, but this sound is not really a buzz in one spot, more of a high pitch buzzing sound from the whole length of a 30"ribbon have new 60" to replace them but have to redo my xovers......crap Im sure loud music had nothing do do with this. I also used the blow dryer trick on my ALiii ribbon. My speakers were fine for 2 years until one day when it was really humid. Then I heard a slight vibration or buzzing sound from one ribbon. I remembered reading somewhere on a Carver forum that they did not like humidity. I used the dryer on low heat, and not too close to the ribbon, and moved it across the front with the foam still on for about a minute. I didn't use them again until the humidity was down. I have not heard the buzzing at all since then- about 2 months. Bob
PMAT 2,038 Posted October 18, 2014 Posted October 18, 2014 Great post Bob. Stick around and join in on more topics.
RobertR 847 Posted October 18, 2014 Posted October 18, 2014 Srinath, A couple of questions on your ribbon work, as I can't help being curious: Did you ever really take that ribbon all the way apart, somehow without totally destroying the Kapton, or did you stop at the point where the picture shows it? Did you ever get that (or any other) malfunctioning Carver ribbon successfully back together again, repaired and working correctly? RobertR 3
srinath 34 Posted October 19, 2014 Posted October 19, 2014 Srinath, A couple of questions on your ribbon work, as I can't help being curious: Did you ever really take that ribbon all the way apart, somehow without totally destroying the Kapton, or did you stop at the point where the picture shows it? Did you ever get that (or any other) malfunctioning Carver ribbon successfully back together again, repaired and working correctly? RobertR The Other side also come off - just as the front one does. I fixed a spot that had a break in the ribbon. But This thing really needs to be re engineered. The magnets acn move easy, the end plates are too flexible and fixing the ribbon is only 1 part of it. I wil llocate a ribbon sometime I hope, and get neo magnets bolted on etc etc. Cool. Srinath.
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