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[RYAN LOUDMUSIC JENKINS]

I showed up at an event last weekend and to my surprise one of my HF drivers wasn't working.  Kind of weird to me as I have never lost one of these HF drivers before.  I had lost a smaller one about 4 years ago.

FYI, this was a B&C DE85.  The one I lost years ago was a B&C DE25.

The next day ofter unloading the gear, I tore open the HF driver to throw another diaphram in it and just like the one I lost a few years ago, there was no evidence of anything wrong.  No burnt marks, no visual breaks in the voice coil, nothin'...

I put a multimeter on it and there was no continuity across the leads.  The replacement diaphram did have continuity.

So I threw the new one in and it works perfect.  Has anyone ever lost an HF diaphram with no apparent reason before?  Did you ever figure it out?

I am thinking maybe I lost them to hard knocks during transportation but who knows.  Can anyone confirm that rough roads would really kill a HF driver?

Thanks a  bunch,  Ryan

[Jim McKeveny]

I've seen plenty of similar failures on DE75/DE750. The break was at the flat-to-voice coil connection, usually on the positive + side. If you get the meter probe in there just right, where ther is no lacquer insulation, you could see continuity in the coil. L'acoustics & B&C used to warranty them, but I became adept at removing peeling back a single coil, stripping insulation, making a better mechanical connection, and soldering the union. I dated them with a marker before reinstalling. Many of these are still working 10 years on.

This only works on full copper coils, not CCAW. Dunno what is in DE85.

[RYAN LOUDMUSIC JENKINS]

Cool to know.  I'll check it out.  The DE 85 uses the same diaphram as the DE75/750.

[RYAN LOUDMUSIC JENKINS]

Just wanted to give Jim McKeveny a BIG thank you!!!!  It was exactly what he described in this thread.  It took me about 10 minutes to fix it.  I already had put a brand new diaphram in the speaker so this one will be a spare but just knowing what the issue is and knowing that I can take care of it is great.

Thanks again,

Ryan Jenkins

[Jon Waller]

I have seen this type of failure in other 'famous maker' HF drivers, so it is not limited to B&C.

[Adam Kane]

I have seen this type of failure in other 'famous maker' HF drivers, so it is not limited to B&C.

Not sure if these are the ones you're referring to or not, but we had the same problems with several Beyma CP385ND drivers. The issues were in loudspeakers from two different manufacturers, but built within a few months of each other. I believe there were 4 bad units in total. Taking the drivers apart yielded findings similar to Ryan's...no visual indication as to why they quit working.

All failures were in systems that weren't run very hard...one happened while listening to some bgm in the shop.

[Ivan Beaver]

I have seen this type of failure in other 'famous maker' HF drivers, so it is not limited to B&C.

I have seen this on quite a few different manufacturers over the years.  Some cheap and some expensive.

Some are easy to fix-others down right hard.

And it is always drivers that have a lot of age on them.

[Jon Waller]

Not sure if these are the ones you're referring to or not, but we had the same problems with several Beyma CP385ND drivers. The issues were in loudspeakers from two different manufacturers, but built within a few months of each other. I believe there were 4 bad units in total. Taking the drivers apart yielded findings similar to Ryan's...no visual indication as to why they quit working.

All failures were in systems that weren't run very hard...one happened while listening to some bgm in the shop.

Since you spilled the beans, Adam, I have seen this on Beyma HF drivers.  We recently did a 'spring tune-up' on a customer's 3-year old ISP line array system.  Out of 96 Beyma HF drivers, 2 had failed.  They both had the failure mode under discussion here.  We replaced the two with new diaphragms free of charge.  I think this type of failure started when Beyma went ROHS compliant and started using lead-free solder, but that's just a guess.  The newer Beyma diaphragms, when inspected under the microscope, have a slightly different method of connecting the coil to the lead-in wires, which looks to be more robust.  They started this some time ago and we have yet to see this failure in the new style diaphragms.

There were no failures of the B&C mids or the Faital LF drivers in this system.

[ProSoundWeb Community]