[bprochford]

I have a pair of N3 towers I built years ago that I've loved every day since I made them. They've worked beautifully and sounded great since day one. A couple days ago I noticed no output at all from both woofer drivers on the left speaker. The tweeter was working properly. I did full checks of all ancillary equipment, cables, etc. determined that it was the speaker that was the issue. In an email, Danny suggested that it was most likely a solder joint on the crossover that went bad, so I pulled the drivers out and checked all of the solder joints - everything was solid.

I de-soldered both drivers and attached each, one at a time, to my speaker cables with music playing and slowly turned up the volume from zero. Nothing. No output whatsoever on either one of the drivers. Both drivers look perfect - no problems or damage to the wiring, cones, etc.

I play music and movies at very reasonable levels and keep my volume down when turning on my system - I wasn't listening to anything at head-banging levels. Also the right speaker still works perfectly and sounds great.

Any ideas on other things I can try, or how on earth this may have happened? I'd love to get everything back up and running, but not sure what my next steps should be.

[Hobbsmeerkat]

If you have a multimeter, check the impedance of both drivers. If they measure fine, then you probably want to take a closer look at the crossover circuit, and check the woofer circuit to see if there's a signal coming thru the circuit if not you may need to check the connection within the crossover.

Hope that helps! 

[bprochford]

Thanks for the suggestion. I checked the DC impedance of each of the two drivers and got no results on either one - multimeter set to measure Ohms, positive probe to positive driver post, negative to negative, and nothing comes up on the meter screen at all. Zero continuity.

So I guess this means it's the drivers? Any ideas how something like this may have happened? One day it was fine, the next completely busted. Does Danny even sell these drivers any more?

[Hobbsmeerkat]

Ahh yeah that's a bummer, but with the fact that both died at the same time is interesting. I'd definitely still look over the crossover to check for a short or issue within the woofer circuit, just in case the issue still exists & may lead to a premature death of any replacement drivers.

Danny still has the M130-16 drivers available here:
http://gr-research.com/m130-16woofer.aspx

[bprochford]

I'm happy to see the drivers are still available. I'm going to dig up another multimeter and double check the impedance, but I'm not too confident, seeing as when I attach an amp directly to the drivers and play some music, I get no sound at all.

Thanks again.

[HAL]

One other thing to test would be the amp output for the channel with the bad drivers.

If the amp is solid state and can work without a load impedance, you might want to check for DC offset voltage on the output terminals for the bad channel as compared to the working speaker channel before attaching the new speakers.  If there is more than ~50mV of DC offset, there might be a problem.  If both channels are close in voltage, then that was not the cause.  The crossover would most likely protect the tweeter, but the woofers would see the DC offset voltage.  Just measure the voltage between the two amp output jacks for that channel.

If it is a tube amp, do not do this measurement without a load impedance.

Best to check this before connecting the new drivers.

[bprochford]

Thanks. I checked the DC voltage across each output of the amp (Arcam integrated) and it's close to zero on both channels. I will reexamine the woofer section of the crossover to see if I missed something. Just so weird that the speaker worked perfectly for almost eight years, then overnight failed. Didn't change anything at all in my setup. Might a power dip or surge across the house mains contribute to this issue? I have fairly robust power protection ahead of the amp, but we do suffer very brief brownouts on occasion.

[HAL]

Since the amp is working correctly, would only think if you heard a pop on that channel during a power glitch that would be the problem. 

Danny will get the drivers sorted out for you once you give him a call. 

[Danny Richie]

Sounds like something took out those drivers. And for two to go at once something had to happen. It sounds like some DC pass through to them some how. The cap inline with the tweeter will not pass DC current. So it is protected.

I will warranty the drivers for any failure that was not a burned or open voice coil.

And yes, I still have them in stock.

[bprochford]

Thanks for responding, Danny. I can ship the drivers back to you to check for warranty purposes. They don't look like they've any damage, but you will know better than I. Either way I'll need to order a new pair, so I can call you later today.