Maybe someone can learn from my mistakes.
Ordered 6 Vifa XT25SC90-04 tweeter clones. They seemed fair enough, even got the Vifa sticker with model name on the back, just like the real thing. Immidiately tested them upon arrival, and lo and behold the results as pictures.
Any ideas what to do with these? They make bad fishing net weights as they have neo magnets. (also waveguide => phase plug, noticed my terminological mistake after editing the picture) 😀
Ordered 6 Vifa XT25SC90-04 tweeter clones. They seemed fair enough, even got the Vifa sticker with model name on the back, just like the real thing. Immidiately tested them upon arrival, and lo and behold the results as pictures.
Any ideas what to do with these? They make bad fishing net weights as they have neo magnets. (also waveguide => phase plug, noticed my terminological mistake after editing the picture) 😀
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You could use the magnets to fish for scrap metal in canals and the like 😀
Not sure what else they could be used for
Brian
Not sure what else they could be used for
Brian
For what it's worth the first three look absolutely fine. There must be some serious voice coil rubbing in the last three.
Technically speaking the part of the dome where the phaseplug sits isn't supposed to move, it's supposed to be fixed.
If you take a normal xt25 and push the phaseplug to the side with enough force it will push the voice coil out of alignment and make it rub. It's possible that the excess glue has caused a similar thing, can you attempt to remove the glue? This might allow the alignment to jump back into place.
The glue, in and of itself, wouldn't cause the distortion, as, as said before, this part of the dome isn't supposed to move anyway. It's possible that the tweeters were damaged during shipping too.
Where did you order them from?
Edit = if you run a 1khz sine wave through the units with high distortion presumably they'll sound fairly terrible. Try doing this and then slowly rock the phaseplug from side to side. By pushing the plug to one specific side it could realign the voice coil and fix the problem completely. The sinewave should go back to sounding clean when you push the plug in the right direction. Obviously this won't be a permanent fix but it will show where the problem lie and how you might go about fixing it.
Technically speaking the part of the dome where the phaseplug sits isn't supposed to move, it's supposed to be fixed.
If you take a normal xt25 and push the phaseplug to the side with enough force it will push the voice coil out of alignment and make it rub. It's possible that the excess glue has caused a similar thing, can you attempt to remove the glue? This might allow the alignment to jump back into place.
The glue, in and of itself, wouldn't cause the distortion, as, as said before, this part of the dome isn't supposed to move anyway. It's possible that the tweeters were damaged during shipping too.
Where did you order them from?
Edit = if you run a 1khz sine wave through the units with high distortion presumably they'll sound fairly terrible. Try doing this and then slowly rock the phaseplug from side to side. By pushing the plug to one specific side it could realign the voice coil and fix the problem completely. The sinewave should go back to sounding clean when you push the plug in the right direction. Obviously this won't be a permanent fix but it will show where the problem lie and how you might go about fixing it.
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Checked again, with all except the intact one, the phase plug is loose. They are probably attached with some kind of adhesive that has failed. Other could be that they were salvaged from Vifa factory reject pile, because these things couldn't get through any sort of quality check. The tweeters are glued shut, if they were screwed on I would open them and realign the coil myself.
They were bought from aliexpress, but you can see similar stuff on eBay.
They were bought from aliexpress, but you can see similar stuff on eBay.
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Sometimes chinese stuff works, sometimes not. I think you can buy six real things for about 120 euros.
I once bought toys from Aliexpress and got money back because they were faulty.
I once bought toys from Aliexpress and got money back because they were faulty.
That glue should be water degradable. At least on Vifa XT it is. You can remove the glue with cotton buds soaked in water and carefully remove the phase plug. Then put healthy amount of neopren based glue into the hole and on to the phase plug and put it back in. Then check if it is centered fine with rub and buzz (DATS) or with music. When it hardens, remeasure. What have you got to lose ?
Actually Aliexpress has pretty good purchaser protection. Open a complaint with the person you bought them from and see what they say. Link this thread to them so they can see the performance issues that you've been having.
My experience of Chinese stuff is very poor.
Transistors that blow far too easily.
I bought 3 flash drives off ebay.
After 2 months they didnt arrive so I got a refund.
After 3 months they did arrive but none worked !
So bought some off Amazon and they arrived 3 days later and all worked and price wasnt much different.
Save a penny and lose a pound !
I think buying a clone is just asking for trouble - but the ribbon tweeters in my Robson standmounts are made in China iirc and they still sound fine five years on. There are some great bargains to be had (e.g. the Topping DAC) but you have to research carefully and anything that looks too good to be true.....
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