Making a LDC Capsule - Videos

[Tim Campbell]

We agree, It doesn't seem to matter.

 

[benqbasic]

Very interesting conversation!! Great info.

 

[GeorgeToledo]

Tim, it was just something said in conversation so I can’t point you to any support, and I did state that. Also, there is a chance I may have misunderstood…I didn’t attempt to pin down any details or what capsules specifically, though it was in general context of the LDC capsules, and specifically in context of adhesion.

As I said, grain of salt. Their process is obviously very secretive, so you can’t pull out a book and go “hey, look, this is where it says so”. But I wouldn’t be aware of the idea of priming the capsule material if it wasn’t for that, so maybe that’s something to consider (though I had heard of priming before deposition in some other contexts).

 

[GeorgeToledo]

On the point about Gefell and the M7…

I would be surprised if Gefell still makes the M7 the way described in early literature about it. Does anyone have links to the bits about making the PVC film, pouring it onto glass? It would be very interesting if they did it exactly the same way they did it in the first years anymore. I’m not sure how relevant whatever “they” DID is as far as what Neumann Berlin went on to do (if we want to consider MTG as somehow being the same company as the original Neumann).

 

[Tim Campbell]

Because there was some question raised as to if membrane material can come in rolls here is a pic of one of my rolls of NOS AKG film from the 60's.
These were made in a linear chamber.

 

[gyraf]

..that's one expensive roll of plastic, if I ever saw one...

/Jakob E.

 

[Murdock]

Are you sre there isn't a way of adjusting the backplate distance with some of those screws? perhaps the one in the center of the backplate or those springs? The backplate looks insulated which would mean the membrane is ground.

I disassembled the whole capsule and you're right. I can set the distance of the backplate to the outer rim by some screws.
Do you have any tips on how to measure distance/gaps in micron range?

Edit: I think I found a tool. But wow, these are expensive...

 

[Tim Campbell]

turn it until the capacitance is about 50 -70pf with the membrane on

 

[kingkorg]

Not a capsule making video, but quite interesting one. Diaphragm tension qc jig can be seen. Some mics you might not think 797 produces. Rode, Audio Technica, Blue...

 

[shabtek]

"R&D Center owns over 50 experts"

Freudian slip?

 

[Tim Campbell]

797 is such a strange company. The East German government forced Michrotech Gefell to teach them about capsule building so they taught them how to build a K67 type capsule but changed critical dimensions so that up until recently chinese K67 capsules were not true Neumann clones because they all just copied 797. Jakob Erland and I once met the head of 797 on Frankfurt Musikmesse. He was very quick to show us schematics of his latest project. He pulled up a schematic of Jakob's G9 and when we pointed out it had Jakob's name on the schematic and that this was indeed Jakob. He didn't quite understand.

They are capable of producing quality product but when I worked on the prototype for Antelope's modelling microphone I was sent a bunch of 797 capsules. The quality control was terrible. Very few capsule halves matched each other and very few capsules matched each other. It could be because Igor was being cheap and just bought their least expensive capsules.

 

[Whoops]

Not a capsule making video, but quite interesting one. Diaphragm tension qc jig can be seen. Some mics you might not think 797 produces. Rode, Audio Technica, Blue...

I only noticed the Blue Snowball on the assembly line, never opened that one, but I fixed the BlueBall which I think it’s a previous model and was assembled with Russian components and not SMD.
Maybe they changed the production to 797 later on with the Snowball models

 

[kingkorg]

They are capable of producing quality product but when I worked on the prototype for Antelope's modelling microphone I was sent a bunch of 797 capsules. The quality control was terrible. Very few capsule halves matched each other and very few capsules matched each other. It could be because Igor was being cheap and just bought their least expensive capsules.

That is really weird. They send me all of the capsules with non smoothed FR certificate and capacitance value measured at factory. All of which measured exactly right at arrival. They could all be used as matched pairs. As i ordered the same model used in Studio Project and Behringer mics over 10 years old i could compare them. They were all insanely close in response despite the age!

I have also the capsules used in TL Sphere and Slate VMS, all matched performance of the capsules found in those mics i had at my place.

Here's one example. The capsule used in Slate ML1, i guess also in Edge Solo

 

[Tim Campbell]

Like I said they are quite capable of doing good work but what I got was terrible. However the best sounding capsule I received out of about 10 manufacturers was a 797 edge terminated one. K67 type backplates but it still sounded really good.

 

[kingkorg]

Single or dual diaphragm?

 

[Tim Campbell]

Dual. I don't really like the single diaphram ones I've heard.

 

[Arni]

I want to share a very interesting article from Audio in 1963. Although it is a cardoid only capsule, it can be changed to omni by metal plugs.

 

[Sonic]

The other day, a colleague asked me to change the diaphragms on the Octava MKL-5000 capsule. On the one hand, the diaphragm was perforated, on the other hand, the metallization partially peeled off. I do not have an installation for applying metallization, so I used a ready-made aluminum metallized film. Excess metallization was removed according to the template with isopropyl alcohol. As can be seen from the photo: the Octava MKL-5000 capsule clones the U87 capsule. And the nature of the sound is similar. After replacing the diaphragms, I tested this capsule on my tube microphone. Perhaps someone will be interested in this information.

 

[kingkorg]

Tim, hi! Now I have taken some photos of the MKE-2 capsule, which I have in my desk. The backplate is made of a dielectric with a metallized layer applied to the front side. The MK-12 backplate and the corrective rear washer are made of metal, but I don't have a photo of them. There is only a general picture.

I have an Octava MK-13M microphone and many of us think that the capsule is a copy of the M7, but I compared the drawing of the M7 with the MK-13 and it is clear from the location of the through holes that they are not in the same places as the original M7.

I have to report my findings on this one. Great news is that the backplate can be used instead of regular chinese MXL603 backplate. Outer rim is slightly smaller but the metal part of the backplate is actually larger than stock chinese. So it is possible to just swap the backplates and just tighten it with the ring so that it sits centered, even though the diameter is smaller.

The capsule itself is slightly smaller than the mxl one, so it can't be just screwed on to the mxl type of mic. Havent tried with Behringer B5, which might work since it has smaller diameter too.

Now the bad part. This thing is as sensitive to adjustments as the original KM84 capsule. After a week of tinkering with it i could not get it to be as flat as i want it to be. Both KM84 and this capsule are insanely sensitive to the ring and center screw tension that tiniest adjustment throws the response way off.

After fixing some km84 capsules in the past i stated that i would never buy a km84 without measuring it first. The same is true for this one.

So if anyone wants to play with these, they have the potential, however i gave up and sold them after tuning them to the best of my ability.

 

[Whoops]

The other day, a colleague asked me to change the diaphragms on the Octava MKL-5000 capsule. View attachment 89251

Are you sure that microphone is an Oktava MKL-5000?
I have an MKL-5000 and it's a different mic than the one you showed in your photos.

Here is the Oktava MKL-5000 I've got:

http://recordinghacks.com/microphones/Oktava/MKL-5000