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by JohnnySomersett_Archive
So, I had a dead M380. After a fair bit of research I came to the conclusion that the required capsule is from the DT770, DT880 & DT990 Headphones from the early 80's. I also spoke to a Beyer spares place here in the UK and to Beyer direct (who weren't a great deal of help to be honest).Turns out that the capsule was shared amongst the top end of the DT range, with the differences in the headphones mainly being how they were baffled, cup construction, etc.So, today arrived these 600 ohm DT880's that were destined for the chopping block (shame, as they are quite a nice sounding set of 'phones):Inside was these capsules:They have a black webbing across the back as a diffuser. The black plastic (as opposed to the M380's white) is apparently just a variation on build years - according to the UK Beyer man.So I CAREFULLY scraped/picked the webbing off to expose the rear holes:And here's the front of the capsule - its mildly tacky which I guess is an old form of 'doping':Installed in the M380 'plate':A perfect fit - thank god for German efficiency in standardisation. Then I carefully glued the felt back panel from the original M380 capsule back on with a few small spots of superglue:...soldered up the wires and put it all back together.Result?Well...it's fixed. It also is, importantly, still a fig-8 pattern!I ran a quick test through my DAW and I can't hear the difference from before it broke. At all. Not a single bit different. Still has the crazy proximity effect and tone. I'll happily admit my ears aren't the best or the most trained...but it's close enough that I can't tell.Now, it's probably obvious by now that I didn't re-install the humbucking coil. WAY too fiddly for my shaky hands and possibly impossible considering how you'd have to move the voice-coil wires - which are stupidly thin! The electricity in my house is pretty clean but there doesn't seem to be any extra hum either...even at high preamp gain levels. It's still CRAZY hot too...barely any preamp gain needed.I think the main things to look for to source a capsule for the mic is to ensure the headphones are 600 ohm and of the same era as the mic for the DT770/880/990 range. And, whatever 'treatment' is on the rear...open up those holes (carefully) so it can pick up soundwaves from the back. The white felt disc that is there to protect the rear of the capsule obviously muffles the response from the rear, thus the difference in sides on the stock M380 as the front only has the metal guard.Some of them (770s) have a plastic 'cap' on the back of the magnet...this can be prised offNB: be super careful picking away the black webbing...I slipped, went too far through and pierced the membrane on the first attempt (there goes my backup capsule).I have got coming to me this week a TG-X 50 that I am going to partially deconstruct to see if it can be made into a figure-8 easily as it seems that opening up the rear of the capsule is key.Anyway.I'm going to eat a baked potato in celebration.FYI, here is a thread that confirms that the DT770, DT880 and DT990 indeed used the same capsule, but just have slight variations on treatment around the capsule to differentiate:http://www.head-fi.org/t/351227/how-to-convert-dt-880-into-dt-990-and-vice-versa-dt-770-infoHere's a link to a sample:http://www.filedropper.com/m380repairVocal test is to demonstrate front/rear difference, done with my lips just touching the grille.Bass is a Peavey T40 into an OR120, mic against the grill dead centre of a Beta 15". No EQ, just raw .wav. MOTU 8pre preamp