Hello, I'm new here and from Bavaria, Germany. I got on the forum because i can offer a handful of notes regarding the M380 capsule. First off, we had one and it died in the early 90s and I was dumb enough not to keep it. My curiosity led me back to it after one day the Sennheiser 602 in the kick had an uncomfortable ammount of bleed from the loud bassamp. (i mostly track full bands in the same room) So I was checking a large number of other mics for the job. The capsule in the M380 was also inside the headphones DT770 and DT990 from 1985 until around 1992, it's the 600 ohms variant. Then the 250 ohms capsule went into those headphones but not to the M380, which weren't made anymore. The Opus 65 and TG-X50 obviously have nothing in common except the housing. For all those who want to look on Ebay for those 80s DT770+990 ... don't get your hopes up too high. Most of them are, after just 30 years or so, in slightly less than stellar condition. I dissected a few I could get my hands on, even after thorough cleaning a good number still has that giveaway buzz when fed low frequency sine tones (also a good way to check AKG D12s, of which IMHO 95% are junk by now). To make matters worse, the audiophiles still hold these 600 ohms DT 770+990 in high regard, which drives prices up. At least those of the sellers, as most buyers are a bit reluctant to trust 30 year old headphones, for a good reason. So, here are my long term plans:-trying to check the spare parts from Beyer, both 250 and 600 ohms if they would work as an old M380 capsule and report back here-trying to get hold of usable old parts from headphones-there is a mystery source for 600ohm capsules from Hungary, but I don't know how many there are-over the years there have been a whole line of capsules for the 770+990 that have nothing in common with the old ones: 32ohms, 50 ohms, 250, new 600ohms, etc.etc. - if you go hunting, keep that in mind - you are much more likely to run into those than the 1985-92 variant. Does anybody have a dead M380 or a capsule? I'd like to see if I can recreate the humbucking coil for the headphone capsules - that would be a faster way than guesswork. The capsule is large, 46mm diameter across, there's not many mic housings they fit into. Anybody by chance would give me their dead M380 for further experiments? The way the capsules were fitted in the mic isn't so different to how it was suspended in the headphones.Another snippet: the old 600 ohms capsules measure around 570-580 ohms DC.

I can't help you with parts but I'm quite interested in your results! Please post here, I'll be watching with interest.

Sorry to interrupt the chase for the capsules (really interested for when mine shit the bed), but what do people use to replace the foam inside these microphones? Beyer were of no help. Seems to me like it's regular headphones foam that is molded into the case. I just don't want to try different types, see that I can't mold them, etc. So if anyone got some foam that worked for them, let me know.

Frans - have you attempted to describe a working capsule? The number of turns of wire, gauge and loop area etc. It's very likely that Beyer used the same forms for several products but changed the winding specifics. A conversion from an available part may just require a rewind.

steve wrote:I can't help you with parts but I'm quite interested in your results! Please post here, I'll be watching with interest.Same here. It's my favorite bass mic, and I can use any info about fixing it I can get...in case it breaks....

From the info i gathered the fact the 600 ohms version is working as we like it might be tied to the mass of the coil together with the membrane. When they changed the wire to make the coil 250 ohms, it got sturdier but it behaved differently. I studied a few of the variants of the headphone capsules and tried them as microphones, but so far none work as good for my like those way-back-600 ohms. Their very thin wire makes them prone to an early demise. They might have used this exact membrane/coil carrier ring elsewhere, but if anybody can pull of the laquered wiring, clean the ring, put on new wire and have it fit the magnet gap without rubbing - phew... This gets on the list of questions I will ask the Beyerdynamic service when I phone them. But taking the humbucking coil apart to DIY it wouldn't be rocket science.Regarding the crumbling foam in them - I'd DIY something out of cheap "cut your own" air conditioner filter stuff. This capsule doesn't like it when hair or something gets in and ever so slightly touches the membrane. Buzzzzzzzz. When hair or -gasp!- dust or -more gasp!- little magnetic particles get into the magnet gap you're usually S.O.L., in a few cases you can reverse the mic as a "speaker" and run a series of sine tones through the capsule via a headphone amp, if you hit the right (resonant, I suspect) frequency you might be lucky and the dirt falls out. (in case of magnetic particles.. no) I had success to fix a few D12 capsules that were buzzing that way. Braver men than me take the capsules apart. I just killed those where I tried it. Even if I learned a few things about capsules that way. For the mic-as-tiny-speaker trick: watch the level. Too little and it doesn't do anything, a bit too much and the coil is toast.

If you believe that the difference in capsules is likely just the voicecoil mass being lighter then you could try the following:-Measure the resonant frequency of the 600R driver in free air (sweep it with an oscillator and note when the impedance measures at a minimum).-Do the same with a later driver like a 250R model, and assuming it's resonant frequency is higher, dope it with PVA glue by applying in a ring near the dust cap (if this exists) until you match the same resonant frequency once the PVA has dried.

I suspect the 250 ohms version has already a higher mass than the thin wire 600ohms, but I got to look further into that.

FransFromBavaria wrote:... Today there is again a 600 ohms version of the DT770 headphone drivers, so far I have no information if they would behave like the M380 capsule, but i am curious enough to try it. Here is a link to Beyerdynamics, Germany spare parts: http://www.beyerdynamic.de/shop/hah/spa ... modell=551i wrote to beyerdynamic germany and they let me know that these capsules are not suitable for the old m380s. that's all the information they gave me.

I've just snagged a pair of early 80's DT880 headphones from German eBay for a good price ( 100)My M380 has been making a cracking noise so I'm gonna try repairing it.Anyone tried this themselves? Easy job? I'm pretty good with a soldering iron.*edit: I've taken mine apart in detail to see if there was obvious issues. The yellow and red wires are still soldered in place but I found 2 whisper-thin traces of copper wire (like, WAY thinner than on the humbucking coil) floating down inside the capsule. I got a tiny set of tweezers and feathered them out but, well, now there's no signal at all. I'm guessing it's toast.I've attacked it with the multimeter and the coil has continuity but the capsule is reading as a broken circuit. When the DT880's arrive I'll disassemble and see what we've got. I'm tempted to just try without the humbucker coil in there as, as a previous poster said, I dont use mine in 'dirty' electrical areas such as live venues etc and he said he couldn't hear the difference - my ears aint the greatest so I doubt I will either. But, i'll see what happens...if it's easy enough to keep it, I will. I cant see in the M380 where the wires from the actual capsule come out! On headphones there's normally 2 connection points on the rim, but there's the weird 'circuit board' stuck to the back of the capsule and its obvious the humbucker wires and in/out wires to the XLR but the actual diaphram ones? Invisible!Will post updates as and when. I'm determined not to have this as an expensive paperweight!