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Post by Mr Trev on Jul 21, 2016 22:34:10 GMT
I'll ask the question here since solderdude is mia at the moment I got a pair of Soundmagic HP150 that suddenly went south on me. I recently swapped back to the stock earpads, and for some reason unknown to me (possibly the same gremlin that ate my P1) one of the drivers is way out of balance now and the phones don't have nearly the volume they used to (I can max my X3 without ripping the phones off my head in pain). It isn't any of the wiring that's causing the problems. I used a different chunk of headphone cable directly to the driver today and measured +6db of difference between the drivers using mono pink noise. Can't see anything physically wrong with the driver in question. Any ideas what's going on? Cheers
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solderdude
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Post by solderdude on Jul 25, 2016 6:43:44 GMT
Do they measure closely the same impedance wise ?
Are they only differing in level, not in tonal balance ? No creaky sounds in the faulty side ?
Is there a warranty on it ?
How do the drivers look ? Is the membrane still in the proper position ?
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Post by Mr Trev on Jul 25, 2016 21:21:55 GMT
Both drivers measure 32.8 ohms
Tonally, hard to tell because of the big level difference, but the "bad" driver will start to distort at volumes over 80db. The good one can easy handle the +-86db.
Haven't removed the drivers from the baffle, but from what I can see through the grill, the membrane doesn't look dented or ripped or otherwise wrong.
The headphones are long out of warranty, but I'm pretty sure the driver has blown somehow. I have sent an email off to see if its possible to get a couple replacements (assuming I should replace both drivers)
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solderdude
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Post by solderdude on Jul 25, 2016 22:40:35 GMT
Weird,
What would be interesting to find out if both driver's membranes can move 'freely' Maybe in the bad one the membane is stuck somewhow and can only move slightly instead of freely ?
From what I read the HP100 also seems to have one driver to go bad in a similar way (less output)
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Post by Mr Trev on Jul 26, 2016 17:04:29 GMT
Stuck driver was one of the things I first thought of. I had the same thing happen to my PFE111 (BA iems). A quick blast of extreme volume, a audible click from the bad armature, and all was go (and still is). Tries the same thing with the HP drivers and all that seemed to do was make the distortion louder. The drivers do have a hole in the centre of the magnet that I can (very)gently blow/suck through and hear a crinkling from both drivers, but obviously I can't see how much the diaphram is moving (probably shouldn't try this too much though)
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Rabbit
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Post by Rabbit on Jul 26, 2016 19:05:04 GMT
Weird, What would be interesting to find out if both driver's membranes can move 'freely' Maybe in the bad one the membane is stuck somewhow and can only move slightly instead of freely ? From what I read the HP100 also seems to have one driver to go bad in a similar way (less output) I have a k545 with uneven drivers. Not sure that it's all frequencies though since it kind of feels odd when you listen and a bit unfocused. Great pity.
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Post by Mr Trev on Jul 26, 2016 19:44:28 GMT
It is too bad considering the 150s are really good phones. Huge soundstage for a pair of closed earphones from what I've read - my first and only pair of closeds. Hopefully a pair of replacement drivers aren't too pricey otherwise I'll be shopping for a new pair
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solderdude
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Post by solderdude on Jul 26, 2016 19:51:10 GMT
The K545 is single entry. If it is the side that does not have the connector in it chances are the interconnection cable or a solderjoint may be faulty.
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Rabbit
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Post by Rabbit on Jul 26, 2016 19:52:11 GMT
To make one channel softer rather than off?
ie; a bad solder joint can cause more resistance? I'll have a look and re-melt the joints then. I just presumed poor matching. It's my bat ears that detect a problem and some might not notice.
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solderdude
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Post by solderdude on Jul 26, 2016 20:09:52 GMT
If the differences have always been there and they are small then driver mismatch. If it developped a clear drop in SPL suddenly or over time it MAY be a solderjoint or maybe a litze wire breaking off a few strands due to bending ?
Had this in 2 HD681's where it was a bad joint on the rods. Not the signal completely gone but much softer in one of them
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Post by Mr Trev on Aug 24, 2016 16:45:58 GMT
Since I haven't gotten any reply from Soundmagic or their distributor I'm thinking I might have to go with 3rd party drivers if I want to resurrect them. Any suggestions for a decent source or a particular driver to look at. A fellow over on Head-fi suggested using Senn. Momentum drivers (dirt cheap ~$10 each), and I've seen quite a few models on Aliexpress (no idea about the quality). Looks like I might be stuck having to adapt 50mm drivers since I haven't found any 53mm
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solderdude
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Post by solderdude on Aug 24, 2016 20:48:26 GMT
They will sound quite different when using other drivers and may not at all have the same sonic properties any more. The looks and comfort will be the only things that have remained the same.
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Post by Mr Trev on Aug 24, 2016 22:45:57 GMT
I do realise that, but whatever I get will still sound better than they do now I'm not adverse to doing some tweaking, after all they are just paperweights atm. Could be a decent little project, even though I know nothing about tuning headphones - how hard can it be I did get another contact tip for Soundmagic so if this one doesn't pan out, then its experimenting time, I guess
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