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#1
Posted to rec.audio.high-end
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B&W Speaker problem
I recently took ownership of a set of B&W speakers that were my
fathers. They saw a lot of use over the years but appeared to be in fine shape. He had them connected to a modified ST-70. My mom wasn't very interested in having a tube amp and set of B&W's so I took them off her hands :-) When I got them back home, I noticed distortion from the low-freq drivers on one speaker. These speakers have two 8" woofers and both were distorting even at low volumes. The midrange and tweeter sounded fine. ( These are B&W model DM640. ) I ended up swapping the drivers from the other speaker into the one that was distorting to determine if it was the crossover and they sounded fine. So, I figure I need to replace the two 8" LF units. I have no idea where to get these. I'm also not sure how they got damaged. The B&W website doesn't have a contact address or any US distributors listed. Anyone know where I can find exact or suitable replacement speakers ? Is it possible the crossover is damaged and could ruin my replacement speakers ? Tom |
#2
Posted to rec.audio.high-end
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B&W Speaker problem
On Mon, 16 Jul 2007 16:05:01 -0700, Tom wrote
(in article ): I recently took ownership of a set of B&W speakers that were my fathers. They saw a lot of use over the years but appeared to be in fine shape. He had them connected to a modified ST-70. My mom wasn't very interested in having a tube amp and set of B&W's so I took them off her hands :-) When I got them back home, I noticed distortion from the low-freq drivers on one speaker. These speakers have two 8" woofers and both were distorting even at low volumes. The midrange and tweeter sounded fine. ( These are B&W model DM640. ) I ended up swapping the drivers from the other speaker into the one that was distorting to determine if it was the crossover and they sounded fine. So, I figure I need to replace the two 8" LF units. I have no idea where to get these. I'm also not sure how they got damaged. The B&W website doesn't have a contact address or any US distributors listed. Anyone know where I can find exact or suitable replacement speakers ? Is it possible the crossover is damaged and could ruin my replacement speakers ? Tom I doubt that the crossover is damaged. Being made up of passive components, it would be real difficult to damage one. Find an authorized B&W dealer. They should be able to tell you how to obtain service and parts, but I suspect that B&W won't sell you the parts, but will, instead, insist that you send the speaker pair to them for repair. Its probably best in the log run that you do so. BTW, replacing the drivers with another make or model won't get you anywhere. There is just no way to know what replacements will match the enclosure or the crossover components of the complete system. IOW, they won't sound the same and likely will sound worse. |
#3
Posted to rec.audio.high-end
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B&W Speaker problem
On Jul 16, 7:05 pm, Tom wrote:
I recently took ownership of a set of B&W speakers that were my fathers. They saw a lot of use over the years but appeared to be in fine shape. He had them connected to a modified ST-70. My mom wasn't very interested in having a tube amp and set of B&W's so I took them off her hands :-) When I got them back home, I noticed distortion from the low-freq drivers on one speaker. These speakers have two 8" woofers and both were distorting even at low volumes. The midrange and tweeter sounded fine. ( These are B&W model DM640. ) I ended up swapping the drivers from the other speaker into the one that was distorting to determine if it was the crossover and they sounded fine. So, I figure I need to replace the two 8" LF units. I have no idea where to get these. I'm also not sure how they got damaged. The B&W website doesn't have a contact address or any US distributors listed. www.bowers-wilkins.com B&W Group North America 54 Concord Street North Reading, Massachusetts 01864 Tel: +1 (978) 664 2870 Fax: +1 (978) 664 4109 Email: Is it possible the crossover is damaged and could ruin my replacement speakers ? Possible, but unlikely. When you replace them, listen at a low level. If the crossover is damaged, it should be plainly audible at these levels as a gross difference between the two speakers. If they sound okay, listen louder, and keep increasing until you get to the levels you'll be listening to. If at each stage, they sound okay, then you're all set. |
#4
Posted to rec.audio.high-end
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B&W Speaker problem
On Jul 16, 7:05 pm, Tom wrote:
I recently took ownership of a set of B&W speakers that were my fathers. They saw a lot of use over the years but appeared to be in fine shape. He had them connected to a modified ST-70. My mom wasn't very interested in having a tube amp and set of B&W's so I took them off her hands :-) OK.... before you go willy-nilly replacing parts or blaming the crossovers, please check a few things first. By implication, you are running the original ST-70 into these same speakers? If not, what are you running into them? If it is the original ST-70, _PLEASE_ check them with another amplifier to make sure that the amp is not the source. Similarly, use a couple of different signal sources, CD, Tuner, etc. Make sure that the speakers are in-phase. Try switching the speakers from channel to channel, not the parts within them. It is *absolutely* possible that a capacitor (if any) within the speaker crossover has crapped out and that could be the cause of your problems. I am not familiar with the components within that crossover, but most of the time and type did have at least one electrolytic cap within them. And they deteriorate with age in many cases. It is quite unusual that bass drivers are damaged by anything other than direct physical damage (a foot through them, for example). Sometimes the surrounds rot, those may be replaced quite easily, even by an amateur with patience and steady hands. There are far too many additional tests to make before blaming the individual drivers. Peter Wieck Wyncote, PA |
#5
Posted to rec.audio.high-end
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B&W Speaker problem
Tom wrote:
I recently took ownership of a set of B&W speakers that were my fathers. They saw a lot of use over the years but appeared to be in fine shape. He had them connected to a modified ST-70. My mom wasn't very interested in having a tube amp and set of B&W's so I took them off her hands :-) When I got them back home, I noticed distortion from the low-freq drivers on one speaker. These speakers have two 8" woofers and both were distorting even at low volumes. The midrange and tweeter sounded fine. ( These are B&W model DM640. ) I ended up swapping the drivers from the other speaker into the one that was distorting to determine if it was the crossover and they sounded fine. So, I figure I need to replace the two 8" LF units. I have no idea where to get these. I'm also not sure how they got damaged. The B&W website doesn't have a contact address or any US distributors listed. Anyone know where I can find exact or suitable replacement speakers ? Is it possible the crossover is damaged and could ruin my replacement speakers ? Tom Removed the speakers from the cabinets and swapped them?? Think I'd have subbed in another amp first or at least swapped the channels of the ST-70. The ST-70 is more likely to have a fault, bad tube, bad cap, etc., than the bass driver being bad. It is possible that the bass driver *is bad*, but less so. The driver*s* (? two of them?) can be tested alone. Remove them from the cabinet. Run each of them with clip leads, magnet side down on a soft surface or hung from a wire with test tones. Your computer can be made to make test tones using either a test CD or some freeware that you can download to emulate a signal generator. If the speaker is bad, you'll here buzz or other distortion. You may find only one is bad or none. Worst case use some music that you know makes it easy to hear this fault. The tones are better. Contact B&W as DP suggested if one or both drivers are bad. _-_-bear |
#6
Posted to rec.audio.high-end
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B&W Speaker problem
Thanks ! I've contacted B&W directly and they are sending me two new
drivers. I found an 800 number (800) 370-3740 for their tech support. Cost was $143.90 each. With any luck I'll have them in a few days. I'll post my results. On Jul 16, 11:31 pm, wrote: On Jul 16, 7:05 pm, Tom wrote: I recently took ownership of a set of B&W speakers that were my fathers. They saw a lot of use over the years but appeared to be in fine shape. He had them connected to a modified ST-70. My mom wasn't very interested in having a tube amp and set of B&W's so I took them off her hands :-) When I got them back home, I noticed distortion from the low-freq drivers on one speaker. These speakers have two 8" woofers and both were distorting even at low volumes. The midrange and tweeter sounded fine. ( These are B&W model DM640. ) I ended up swapping the drivers from the other speaker into the one that was distorting to determine if it was the crossover and they sounded fine. So, I figure I need to replace the two 8" LF units. I have no idea where to get these. I'm also not sure how they got damaged. The B&W website doesn't have a contact address or any US distributors listed. www.bowers-wilkins.com B&W Group North America 54 Concord Street North Reading, Massachusetts 01864 Tel: +1 (978) 664 2870 Fax: +1 (978) 664 4109 Email: Is it possible the crossover is damaged and could ruin my replacement speakers ? Possible, but unlikely. When you replace them, listen at a low level. If the crossover is damaged, it should be plainly audible at these levels as a gross difference between the two speakers. If they sound okay, listen louder, and keep increasing until you get to the levels you'll be listening to. If at each stage, they sound okay, then you're all set. |
#7
Posted to rec.audio.high-end
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B&W Speaker problem
Tom wrote:
Thanks ! I've contacted B&W directly and they are sending me two new drivers. I found an 800 number (800) 370-3740 for their tech support. Cost was $143.90 each. With any luck I'll have them in a few days. I'll post my results. Shouldn't you have tried swapping the 'bad' drivers into the 'good' cabinet, first? If they didn't sound distorted , it wasn't a driver problem in the first place. On Jul 16, 11:31 pm, wrote: On Jul 16, 7:05 pm, Tom wrote: I recently took ownership of a set of B&W speakers that were my fathers. They saw a lot of use over the years but appeared to be in fine shape. He had them connected to a modified ST-70. My mom wasn't very interested in having a tube amp and set of B&W's so I took them off her hands :-) When I got them back home, I noticed distortion from the low-freq drivers on one speaker. These speakers have two 8" woofers and both were distorting even at low volumes. The midrange and tweeter sounded fine. ( These are B&W model DM640. ) I ended up swapping the drivers from the other speaker into the one that was distorting to determine if it was the crossover and they sounded fine. So, I figure I need to replace the two 8" LF units. I have no idea where to get these. I'm also not sure how they got damaged. The B&W website doesn't have a contact address or any US distributors listed. www.bowers-wilkins.com B&W Group North America 54 Concord Street North Reading, Massachusetts 01864 Tel: +1 (978) 664 2870 Fax: +1 (978) 664 4109 Email: Is it possible the crossover is damaged and could ruin my replacement speakers ? Possible, but unlikely. When you replace them, listen at a low level. If the crossover is damaged, it should be plainly audible at these levels as a gross difference between the two speakers. If they sound okay, listen louder, and keep increasing until you get to the levels you'll be listening to. If at each stage, they sound okay, then you're all set. -- ___ -S "As human beings, we understand the world through simile, analogy, metaphor, narrative and, sometimes, claymation." - B. Mason |
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