Yamaha NS-1000X tweeters blown...whats the problem?

[young_pup]

Hi guys,

Imported these fine NS-1000X speakers and the tweeters on both seem to have gone.

What could have caused this? The speakers were both packed very well.

All other drive units function (mid and woofer).

How could i test the tweeters with a multimeter?

Anyone know where i can get spares?

Regards

Richard

 

[cyclotronguy]

Tweeter

Ohm reading directly across the tweeter should give you several ohms of resistance. A reading of near zero or open indicates problems.

How can a tweeter be damaged, amplifier clipping, overdriving to the point of thermal failure, corrosion, physical abuse..... etc.

 

[young_pup]

problems with what?

Does the resistance indicate problems with tweeter or crossover?

Thanks!

Richard

 

[Cal Weldon]

If it is a 4 ohm driver, it should read around 3 ohm resistance

8ohm driver = approx 6.5 ohms resistance plus or minus

That's what they should read if they are OK.

If it's zero = dead tweeter

If it's almost infinite, maybe blown tweeter, maybe broken lead

Tell us what you are hearing that makes them sound blown. Do they make sound at all?

Cal

 

[Cal Weldon]

To check the XO hook up a tweeter you know is good.

Also, try bypassing the L-pads to see if that might be it.

 

[Paul Dimaline]

Richard,

Yamaha UK can supply all parts for these fine speakers new, just make sure your sat down when they tell you the price! (Mids are around £350 each )

Paul.

 

[young_pup]

measured value

hi guys,

Yeah i measured the resistance and found 3.5ohms across one of them. I think they're a six ohm speaker.

Far out but could it be that i'm using a very cheap sherwood amp? rated at 8ohms?

Could it be the crossover? I ordered new tweeters from yamaha though to find out...in japan they're much cheaper.

I'll try hooking up a known tweeter to see what happens...let the diagnosis begin!

Richard

 

[young_pup]

no sound

yeah i'm getting sound from the midrange and woofer but not the tweeter....any advice?

Richard

 

[jez]

Are there any tweeter fuses? could be on crossover.
You say that one measures 3.5 ohm, that's not incorrect if it's a 4 ohm tweeter (evan if the whole speaker says 8 or 6 ohms on the back, it may use 4ohm tweeters), what does the other measure? if they are not the same (within a few percent) you have a problem!
Looks like the crossover could have a problem if still no sound with good tweeter, is this the case for both speakers?
Crossovers often have resistive pads or simple in-line resistor to match HF level to mid, could one of those resistors blown. Good luck.
jez

 

[young_pup]

measured values

Are there any tweeter fuses? could be on crossover.
You say that one measures 3.5 ohm, that's not incorrect if it's a 4 ohm tweeter (evan if the whole speaker says 8 or 6 ohms on the back, it may use 4ohm tweeters), what does the other measure? if they are not the same (within a few percent) you have a problem!
Looks like the crossover could have a problem if still no sound with good tweeter, is this the case for both speakers?
Crossovers often have resistive pads or simple in-line resistor to match HF level to mid, could one of those resistors blown. Good luck.
jez

Jez...i measured the resistance across both tweeters and it read the same...3.5ohms. So does that mean its something else or than a faulty tweeter? Or could it still be the tweeters?

Or could it be my little sherwood standin amp just can't power them if they're 4ohms? I do have an Accuphase E307 but its yet to be rewired!

Only problem now is getting to measure the crossover or check it out...the cabinets are sealed and the crossover is right at the back

Any further ideas?

Richard

 

[jez]

If both tweeters measure 3.5ohms then they are probably ok.
It's not your amp!.
Get a 1.5 volt battery such as an AA and connect it intermittantly accross the tweeter terminals, you should hear a tinny sounding crackle as the connection is made and un-made, dont use more than 1.5 volts and don't leave it connected. If they pass this test then it's even more likely they are OK. Do check for hidden fuses.
Jez.