View Full Version : Pointers for buying used comp diaphragms?

moray james
08-26-2013, 11:54 AM
are there any threads which discuss and have pictures of what things to be looking for when buying used compression driver diaphragms? will diaphragms which have slapped a phase plug show signs? If a VC measures in spec and looks like new always be ok? What kind of things are to be expected or should a perfect used diaphragm always look perfect and like new? Thanks for any advice or recommendations. Best regards Moray James.

08-26-2013, 12:21 PM
I don't think I would do it unless they were cheap enough that I wouldn't be upset if they were trash.

Although there was a pair of truextent diaphragms for jbl 4 minders on ebay for 200 once. If I would have had the cash I would have gambled. As is I didn't and it ended at 200 without a bid.

The other would be if you know the person your buying them from.

The only thing I know to look for is the 2 little dents put in the diaphragm when the wire hits is when changing the phragm. That's all the knowledge I got.


08-26-2013, 02:02 PM
Realize that diaphragms are parts intended to be replaced and you will suffer fewer disappointments.
An aluminum one can look perfect, right before it shatters from work hardening... or it can be fine.

moray james
08-26-2013, 02:17 PM
grumpy that's what I was worried about. Short of installing them for a listen or having trust in the vendor it's not looking like a great idea to buy used. Appreciate the input guys . Best regards Moray James.

08-26-2013, 03:51 PM
Yeah, keep in mind that they're wear parts in pro usage and you're good. Usually a good inspection is useful, if the former looks like it's melted, or there's damage on the dome, natch, it's possibly replacement time. Though formers often discolor long before having a major issue.

Run an impedance sweep, make sure they sound okayish with test tones and you ought to be pretty good.

And yeah- don't overpay :)

08-26-2013, 09:28 PM
Something I've seen several times before is very hard to see, especially in pics. One Ti dome I bought turned out to be useless when I discovered that the former had swelled enough to restrict motion, it was literally stuck on the pole piece. Another pair pair came like that on drivers, hardly any sound came out of them despite the perfect DCR.

Not sure what caused them to swell, heat or moisture maybe. Just make sure that you can either return them or get a refund of all your money...

moray james
08-26-2013, 11:08 PM