I have some old Interdyn 10” 2 ways with a SEAS H211 tweeter, one of which was cooked.
I measured the magnet as 25.4mm and ordered some replacement voice coils/domes for a 1” tweeter and what was supplied was a voice coil that is also 25.4mm - which does not fit in the gap in the magnet.
Should I be ordering a different size, or should the 1” dome voice coil actually be a little bit bigger?
I measured the magnet as 25.4mm and ordered some replacement voice coils/domes for a 1” tweeter and what was supplied was a voice coil that is also 25.4mm - which does not fit in the gap in the magnet.
Should I be ordering a different size, or should the 1” dome voice coil actually be a little bit bigger?
Can you re measure the gap, alternatively can you measure the damaged domes coil inner and outer diameters. That information should provide the reason why you have a mismatch on coil size?
Save some money and return the replacement coils.
If they were an eBay purchase the seller may not like the idea of returns or will have limit.
Save some money and return the replacement coils.
If they were an eBay purchase the seller may not like the idea of returns or will have limit.
There are quite a few currently available Seas voice coils:
https://www.madisoundspeakerstore.com/seas-voice-coils/
I wouldn't be surprised if one of those would fit, even if some frame surgery might be required, but coil diameters are more likely to be consistent for a given manufacturer (I've carried out some transplants from Peerless to Peerless and Vifa to Vifa without trouble). If I were you I'd drop a line to Seas and ask, they may be able to help.
https://www.madisoundspeakerstore.com/seas-voice-coils/
I wouldn't be surprised if one of those would fit, even if some frame surgery might be required, but coil diameters are more likely to be consistent for a given manufacturer (I've carried out some transplants from Peerless to Peerless and Vifa to Vifa without trouble). If I were you I'd drop a line to Seas and ask, they may be able to help.
the damaged coil was in pretty poor shape, the wires had melted and overlapped and it wasn't stable enough to measure. I've used calipers to measure as best I can, the outside of the inner magnet is 25.4mm and the inside of the outer magnet is 27mm. The problem is that the new coil was exactly 25.4mm. I'm guessing that it should have an inner diameter of around 26mm
[EDIT] Based on the other comment I looked up the SEAS website and indeed the 1" tweeters have a voice coil diameter of 26mm....
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SEAS confirmed that I need 25.8mm internal/26.5mm external.
The challenge now is sourcing one that is economical. For me to buy voice coils from Madisound with shipping would be more expensive than buying new tweeters locally, but they are all 8 ohms rather than 6.
The challenge now is sourcing one that is economical. For me to buy voice coils from Madisound with shipping would be more expensive than buying new tweeters locally, but they are all 8 ohms rather than 6.
Are you quite sure that the new tweeters would be 8 ohms? Their DC resistance might lie somewhere within the 5–6 ohm range.
Can you measure the DC resistance of the undamaged H211?
Can you measure the DC resistance of the undamaged H211?
It measures at 6.0 Ohms. The voice coils I ordered as replacements were nominally 6 and measured at 6.5
To be clear, my source of new voice coils (not madisound) at 26mm are all nominally 8 ohms.
View attachment 1339165
To be clear, my source of new voice coils (not madisound) at 26mm are all nominally 8 ohms.
View attachment 1339165
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So I have some new voice coils now.
Just wondering a few things:
I’ve ordered some ferrofluid as well.
Just wondering a few things:
- is it most likely that these leads are coated, or do I need to put down tape or something so they don’t short against the frame
- is there any special trick to making sure they are aligned
- should I put some glue on the edge of the dome or is the sticky plastic likely to be enough to hold it in place?
I’ve ordered some ferrofluid as well.
The image with the coil lying face down and with shows there is some kind of plastic film there. Maybe that is non conductive? You could test by gently applying your DVM probes and see that it measures open circuit.
As to the magnet side what does that look like for insulation, and in fact does it sit away from the faceplate on punched circular supports around the mid diameter.
Your question of alignment should come via the 4 mounting holes for the faceplate it would seem. as i cannot se any other holes in the support assembly of the replacement dome for any alignment spigot pins.
As to the magnet side what does that look like for insulation, and in fact does it sit away from the faceplate on punched circular supports around the mid diameter.
Your question of alignment should come via the 4 mounting holes for the faceplate it would seem. as i cannot se any other holes in the support assembly of the replacement dome for any alignment spigot pins.
The wire has an insulation lacquer on it. You need to scratch it off where you want to solder it. It would be good to fix the leads in place with a tape, roughly in the middle of the lead. However, the tape or lead may not be squeezed, that would indicate the front plate doesn't sit right and the tiny gap makes the dome create noise.
Have a look at this.
He seems to use a yellow tape possibly Kapton. The second video is for a celestion HF1000 tweeter which is worth a look.
He seems to use a yellow tape possibly Kapton. The second video is for a celestion HF1000 tweeter which is worth a look.
Yes, that's Kapton.
If the paper gasket isn't very soft, he did exactly what he should not have done. Plus, at the edge of the front pole plate squishes the lead - which is not good either because that can scrape off the isolation laquer. He really should have run the leads on the front of the face plate. Or do this:
Some good points and clarification in the above from ICG.
Maybe I was a bit quick on the posting the link.
Maybe I was a bit quick on the posting the link.
Thanks. The coils measure 5.8 Ohms which is very close to the originals (great) but when I mount it in the magnet I’m getting 0.4 Ohms so I assume my wires aren’t well insulated. I’ll find something, I don’t have that yellow stuff.
Plus I can play that Youtube video to test the frequencies!
Plus I can play that Youtube video to test the frequencies!
I finally got around to fixing these. I needed the kapton tape to isolate the wires.
I’m relying on the overlay tape/gasket to hold the dome in place (ie I haven’t glued it to the face plate) and I haven’t put in any ferrofluid, but it now works and sounds as good as its old matching pair.
I’m relying on the overlay tape/gasket to hold the dome in place (ie I haven’t glued it to the face plate) and I haven’t put in any ferrofluid, but it now works and sounds as good as its old matching pair.