Studio 939 — Home. Debenham-StereoCondenser.pdf. Diy mic capsule - Page 3 - RECORDING.ORG. Debenham, Stebbings, and Robinson Capsule. This is a Debenham, Stebbings, and Robinson capsule.
It sounds very nice and is not very fussy as to diaphragm tensioning. Recommended for a first DIY. Outer plastic is Delrin. To stick it to brass, you MUST use Loctite 770 primer followed by the thinnest cyanoacrylate you can find. Even that may not work correctly. DIY Audio Stuff. First, I must mention the best DIY pro audio board on the web, "The Lab" . My projects are/have been: Neve 1290 clone RCA BA31A clone My own preamp design Gyraf G1176 Jensen JE990 discrete op-amp - built one. Fairchild 660 rough clone - I built it by following half of the 670 schematic but substituting some tubes. LA4 rough clone - improved audio path, high-speed opto compression mode - haven't finished it yet My own SSM2081 feedback compressor design Neve 2254 Compressor - nice compressor.
Gates M6629 Modifications. Figuring out how the Lexicon ARU chip works. These are photos of my DIY tube microphone. These are photos of my DIY tube microphone. Details? The capsule is my attempt at duplicating a Neumann M7 capsule. The capsule uses a glued-in diaphragm (like the M7) but made of 6 micron mylar (unlike the M7's 10 micron PVC material). A gold coating of somewhere between 50 and 150 angstroms has been applied to the film (I do that too). It is tensioned to a resonance of about 950 Hz, which is quite similar to the tuning of the original M7 capsules. Making an M7 Copy. This is a photo of tensioning the diaphragm. This is just a photo shoot - the diaphragm in question was wrecked by careless application of glue.
A glued diaphragm is attached by gluing the underside of the diaphragm to the capsule and it's easy for the glue to wick underneath the diaphragm and ruin the works. This diaphragm met that fate, but was recycled to show you how I tension the diaphragms. A mass of 120 grams should result in a diaphragm resonant frequency of about 950 Hz. Care must be taken while mounting the diaphragm to the mounting ring to ensure even tension distribution. And this is CNC drilling of the capsule. And here are six capsules, tested, and ready to go. Photos of deposition system. Photos of my vacuum thermal evaporator. This was the first run. I only set up one target (diaphragm) for this run. I currently have space for seven targets at once. This photo is of the inside of the chamber. The brass clamps hold a small tungsten heater (boat) where nickel or gold wire is placed for the evaporation. Film Vendors. This is a photo of tensioning the diaphragm. I've updated my process a bit so there are more things to show....
This is a shot of a lathe machining the 'final cut' into a capsule. This is a critical cut - there are features on this cut that must be with about two microns (around a tenth of a thousandth of an inch). The early capsules, and carryover backplates from earlier batches, are machined manually. New production is done with CNC control of the same (Sherline) lathe. I am using a Levin Lathe machinable 8mm collet to hold the part - a normal jaw-equipped chuck will not work. This is underneath the cover of the gold coating machine.
Here you can see the glow of the filament. Things have to be clean. The diaphragm needs to be primed for glue. Chambered Capsules. This is a newer capsule creation, a multi-chambered capsule built using the AKG original CK12 patent for measurements. No audio files yet, but so far it sounds pretty good. I built three pairs of plates, the ones shown are 170 micron gap, the ones in the mic are 220 microns, which is close to the dimension of 200 microns shown in the AKG/Siemens patent. A 40 micron spacer is used between the capsule halves. This spacer is used to tune the frequency response, and I have not taken the time to adjust this carefully yet.