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Post by jeeperjk on Dec 4, 2021 12:28:01 GMT -5
Hi all - I recently had TWO voice coils burn from the left & right speakers (Ascend Sierra towers). My XPA-11 is hooked up to a Marantz AV7705, and when this happened I was playing music in stereo about -8 to -6db. I've done a bit of research on this and a couple of forums as well, and a lot of the feedback that I'm getting are pointing towards the amp. Best I've settled on is that perhaps there was a transistor that failed when reaching a certain temperature under the load. I've hooked up a cheap speaker to the amp and don't hear any humming or pops when turning on/off, so if there is an issue, it's not consistent. Does anyone know if this amp has any protections against DC offset? The specs page doesn't quite say it other than saying 'common fault tolerances' ... Would also like to get the amp tested and any thoughts/feedback on that would certainly be appreciated as well. Related thread over at audioholics: forums.audioholics.com/forums/threads/ascend-sierra-tower-emotiva-xpa-11-burnt-voicecoil.123945/Cheers! |
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Post by 405x5 on Dec 5, 2021 11:02:11 GMT -5
Hi all - I recently had TWO voice coils burn from the left & right speakers (Ascend Sierra towers). My XPA-11 is hooked up to a Marantz AV7705, and when this happened I was playing music in stereo about -8 to -6db. I've done a bit of research on this and a couple of forums as well, and a lot of the feedback that I'm getting are pointing towards the amp. Best I've settled on is that perhaps there was a transistor that failed when reaching a certain temperature under the load. I've hooked up a cheap speaker to the amp and don't hear any humming or pops when turning on/off, so if there is an issue, it's not consistent. Does anyone know if this amp has any protections against DC offset? The specs page doesn't quite say it other than saying 'common fault tolerances' ... Would also like to get the amp tested and any thoughts/feedback on that would certainly be appreciated as well. Related thread over at audioholics: forums.audioholics.com/forums/threads/ascend-sierra-tower-emotiva-xpa-11-burnt-voicecoil.123945/Cheers! How close to a “live” listening level would you (guesstimate) were you at when the problem made itself apparent? |
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Post by DavidR on Dec 5, 2021 11:15:12 GMT -5
Hi all - I recently had TWO voice coils burn from the left & right speakers (Ascend Sierra towers). ................................................................. Does anyone know if this amp has any protections against DC offset? The specs page doesn't quite say it other than saying 'common fault tolerances' ... Cheers! I do not know for sure but most amps, even older ones, have DC offset within the fault condition.
It's generally not excessive volume (watts/current) that kills a driver but is due more to distortion.
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Post by jeeperjk on Dec 5, 2021 12:18:39 GMT -5
Hi all - I recently had TWO voice coils burn from the left & right speakers (Ascend Sierra towers). My XPA-11 is hooked up to a Marantz AV7705, and when this happened I was playing music in stereo about -8 to -6db. I've done a bit of research on this and a couple of forums as well, and a lot of the feedback that I'm getting are pointing towards the amp. Best I've settled on is that perhaps there was a transistor that failed when reaching a certain temperature under the load. I've hooked up a cheap speaker to the amp and don't hear any humming or pops when turning on/off, so if there is an issue, it's not consistent. Does anyone know if this amp has any protections against DC offset? The specs page doesn't quite say it other than saying 'common fault tolerances' ... Would also like to get the amp tested and any thoughts/feedback on that would certainly be appreciated as well. Related thread over at audioholics: forums.audioholics.com/forums/threads/ascend-sierra-tower-emotiva-xpa-11-burnt-voicecoil.123945/Cheers! How close to a “live” listening level would you (guesstimate) were you at when the problem made itself apparent? I'm not sure what you mean here... are you asking what the actual db level would've been in the room? I have no idea. One thing I can say is that trim levels for the speakers were zero as well for music; I had not increased them. Hi all - I recently had TWO voice coils burn from the left & right speakers (Ascend Sierra towers). ................................................................. Does anyone know if this amp has any protections against DC offset? The specs page doesn't quite say it other than saying 'common fault tolerances' ... Cheers! I do not know for sure but most amps, even older ones, have DC offset within the fault condition.
It's generally not excessive volume (watts/current) that kills a driver but is due more to distortion.
The source is what I would call clean... playing music from Tidal. |
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Post by DavidR on Dec 5, 2021 12:45:36 GMT -5
But at that volume there is a high probability of running out of power = clipping = distortion.
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Post by jeeperjk on Dec 5, 2021 12:50:30 GMT -5
But at that volume there is a high probability of running out of power = clipping = distortion.
Exceeding 490w? I'm not super technical, but that seems a bit of a stretch
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Post by DavidR on Dec 5, 2021 14:47:15 GMT -5
 Specs for your speakers from their website. At the level you were pumping power into your speakers you probably exceeded their power handling capability.
I didn't realize the XPA-11 was capable of that much power.
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Post by jeeperjk on Dec 5, 2021 15:14:09 GMT -5
<button disabled="" class="c-attachment-insert--linked o-btn--sm">Attachment Deleted</button> Specs for your speakers from their website. At the level you were pumping power into your speakers you probably exceeded their power handling capability.
I didn't realize the XPA-11 was capable of that much power.
I was playing, let's say -6db... which would've been tops. I don't see how this would exceed the capacity of either the amp, or the towers. These are pretty solidly built, and there are folks who play them at a much higher level consistently. Not trying to be argumentative, but I think it's just very easy to say "played too loud" and be done. The components in the lineup I have are not what would call super high-end, but they are not exactly something cheap you might pick up on sale at BestBuy. And I was enjoying these maybe a little higher than average, but nowhere near manufacturer specs when something failed. I'm just trying to figure out what the root cause is so I can get it fixed and not have it happen again. A DC offset happening under certain circumstances is the most likely scenario I've gathered so far... However, if the amp has that protection built-in then we can rule that out and move on. Find it strange that it's not mentioned in any of the specs... maybe it's so fundamental that it's a given... but I'd like to have some confirmation. The email I've sent to support has not been responded to yet, even though my earlier queries were answered within minutes. |
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Post by doc1963 on Dec 5, 2021 15:39:42 GMT -5
Out of curiosity, what are the trim levels found in the “speaker setup” menu on your AV7705 on the two channels affected…?
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Post by jeeperjk on Dec 5, 2021 15:46:23 GMT -5
Out of curiosity, what are the trim levels found in the “speaker setup” menu on your AV7705 on the two channels affected…? Trims were at zero |
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Post by DavidR on Dec 5, 2021 15:55:25 GMT -5
300 watts MAXIMUM CONTINUOUS POWER. That would be a lot lower than -6dB
too easy to blame Emotiva IMO
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Post by jeeperjk on Dec 5, 2021 16:10:29 GMT -5
300 watts MAXIMUM CONTINUOUS POWER. That would be a lot lower than -6dB too easy to blame Emotiva IMO I'm not blaming anyone here. As I've repeatedly said, I'm trying to understand what happened and then take things from there. If you look at my original post over at Audiholics as well, I've tried my best to not to blame any manufacturer. I understand that sometimes sh!t happens... so there's really no reason to be defensive about anything or point fingers at anyone else. The simple question I'm trying to get answered in this forum is whether or not the amp has DC offset protection built in. If it does, we move on. If it does not, perhaps investigate a little further.
If in fact what your saying is possible, and that speakers were being over-driven, shouldn't the tweeters bust first?
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Post by doc1963 on Dec 5, 2021 16:12:54 GMT -5
Out of curiosity, what are the trim levels found in the “speaker setup” menu on your AV7705 on the two channels affected…? Trims were at zero Zero…? Did you not run Audyssey and let it adjust your speaker trims for you…? I only ask because DAC only have about 10dB of headroom and if your playback volume was -6dB with zero trim, I suspect that your signal coming out of the 7705 was already clipping. Your amplifiers can only magnify that distortion. While I wouldn’t rule anything out, I think your voice coils were damaged by clipping distortion in the signal rather than a DC fault condition originating in the amp and then, somehow, making it past its protection circuits. But if you want to rule it out, request that Emotiva take a look at it. I don’t suspect that they’ll find anything wrong, so expect to pay shipping both ways… |
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Post by doc1963 on Dec 5, 2021 16:15:49 GMT -5
300 watts MAXIMUM CONTINUOUS POWER. That would be a lot lower than -6dB too easy to blame Emotiva IMO I'm not blaming anyone here. As I've repeatedly said, I'm trying to understand what happened and then take things from there. If you look at my original post over at Audiholics as well, I've tried my best to not to blame any manufacturer. I understand that sometimes sh!t happens... so there's really no reason to be defensive about anything or point fingers at anyone else. The simple question I'm trying to get answered in this forum is whether or not the amp has DC offset protection built in. If it does, we move on. If it does not, perhaps investigate a little further. If in fact what your saying is possible, and that speakers were being over-driven, shouldn't the tweeters bust first? Not necessarily… If it’s the RAAL tweeters, they’re a bit more forgiving. |
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Post by jeeperjk on Dec 5, 2021 16:29:35 GMT -5
Zero…? Did you not run Audyssey and let it adjust your speaker trims for you…? I only ask because DAC only have about 10dB of headroom and if your playback volume was -6dB with zero trim, I suspect that your signal coming out of the 7705 was already clipping. Your amplifiers can only magnify that distortion. While I wouldn’t rule anything out, I think your voice coils were damaged by clipping distortion in the signal rather than a DC fault condition originating in the amp and then, somehow, making it past its protection circuits. But if you want to rule it out, request that Emotiva take a look at it. I don’t suspect that they’ll find anything wrong, so expect to pay shipping both ways… Audyssey did calibrate, but that was for movies. For this particular occasion, I was listening stereo and the trims were set to zero. I wouldn't mind paying shipping and having the amp checked, but haven't heard anything back yet. My last email to them was Friday am, and hopefully I'll hear something tomorrow. The last few emails I sent they were pretty fast to reply. |
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Post by jeeperjk on Dec 5, 2021 16:32:21 GMT -5
Not necessarily… If it’s the RAAL tweeters, they’re a bit more forgiving. I do have the RAAL's... |
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Post by 405x5 on Dec 5, 2021 20:20:43 GMT -5
How close to a “live” listening level would you (guesstimate) were you at when the problem made itself apparent? “I'm not sure what you mean here... are you asking what the actual db level would've been in the room? I have no idea.” Well, what I mean here is the kind of trouble you’ve experienced is most commonly caused by over driving your loudspeakers. Unlikely in my experience yours is a fault in the amplifier |
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Post by DavidR on Dec 5, 2021 21:31:12 GMT -5
You really haven't explained exactly what happened. From your opening statement I'm not sure if 2 drivers in EACH cabinet went or one driver in each cabinet. No idea which driver either. You haven't said if the "TWO" drivers just stopped working and the other drivers continued to play. IF a TIP transistor let go and allowed DC current to pass to the speakers then the woofers would burnout before other drivers. Woofers have no capacitors in the series position to block DC; as it will not pass thru a capacitor (but they have a voltage limitation). Other drivers have some protection via the speaker crossover series capacitor. The amp would have shutdown on speaker protection. Subsequent attempts to turn ON the amp would likely never get past the circuit protection shutdown mode.
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Post by jeeperjk on Dec 5, 2021 21:54:32 GMT -5
You really haven't explained exactly what happened. From your opening statement I'm not sure if 2 drivers in EACH cabinet went or one driver in each cabinet. No idea which driver either. You haven't said if the "TWO" drivers just stopped working and the other drivers continued to play. IF a TIP transistor let go and allowed DC current to pass to the speakers then the woofers would burnout before other drivers. Woofers have no capacitors in the series position to block DC; as they will not pass thru a capacitor. Other drivers have some protection via the speaker crossover series capacitor. The amp would have shutdown on speaker protection. Subsequent attempts to turn ON the amp would likely never get past the circuit protection shutdown mode. Yeah, my bad for leaving some of that background out. I was just jumping straight to the specs/fault-protections of the amp. To answer your question, each tower has one midrange woofer. And both of those had burned voice coils. In one, there was no sound coming at all from the midrange. In the other, there was sound but distorted... Both of these woofers had the distinct burnt rubber smell. |
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Post by DavidR on Dec 5, 2021 22:11:12 GMT -5
 So the top driver is the midrange? Two lower are woofers and the ribbon between the mid and woofer? It would be odd for a DC issue to burnout a driver that has a series capacitor and not the woofers.
So does the amp still work?
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