Making a LDC Capsule - Videos

[Tim Campbell]

Yes Stephen and I became friends via the internet for the last years before he died and had quite a few interesting discussions.

 

[Whoops]

This will work if quality isn't of any importance. A properly manufactured capsule can be mirror smooth without causing attraction. Even when Neumann placed bumps onto the surface of their K67 capsule it could still collapse when working improperly. High spots, contamination or too low a tuning tension for the membrane compared to polarization voltage are the most common cause of collapse. Roughness is used as an attempt to help the membrane release once it has hit the backplate.

Many chinese capsule backplates are highly polished without problem.

Thank you for joining in Tim, and thanks for your contribution

 

[wave]

I don't spend much time posting on here or RGO these days, but one thing I always see is Tim chiming in to anything Eric has to say.
Tim you're like a little girl. I'm so sick of your "fight" you keep perpetuating with Eric. Go do something else.
End of rant

 

[Whoops]

Wave you are out of line here, personal attacks are against the forum rules, your post was reported to the moderators

both Eric and Tim provided useful info and contributions to this thread and no one was disrespectful, but you were.
Please take your war rants to another place

 

[JohnRoberts]

I don't spend much time posting on here or RGO these days, but one thing I always see is Tim chiming in to anything Eric has to say.
Tim you're like a little girl. I'm so sick of your "fight" you keep perpetuating with Eric. Go do something else.
End of rant

rules

4. You will find that the members of this community are courteous and respectful of each other, so please reciprocate those gestures. Leave the flame-war mentality at another forum. Personal attacks and generally hateful comments (regarding race, religion, gender, sex, etc...) will not be tolerated.

BE NICE


JR

 

[soliloqueen]

Does anyone have any insights on dusting membranes post-gold? I've been using this which is safe for delicate gold leaf with good results.

 

[Whoops]

I use a very thin and soft brush and distilled water.
It's a very gently and slow process, don't do any pressure on the diaphragm and don't brush it, just lightly move the water with the brush,
remember very lighly

 

[JohnRoberts]

You guys don't realize how close I am to locking this thread... start drinking and stop whining.

JR

 

[Khron]

I've cleaned a few cheapie k67 capsules with a little wad of cotton wool held in the tip of a pair of tweezers, and soaked with isopropyl alcohol (but not dripping though). Have yet to manage to peel / flake off any of the gold though.

Can't say whether or how much of a difference that made, but in at least one case it was part of troubleshooting some noise (which turned out to come from the circuit itself, after all).

 

[Gus]

I would not use any liquid cleaning in this thread on an older capsule. The gold will flake off

EDIT New capsules are more robust
The evaporated gold flakes off on older capsules with some liquid cleaning techniques.
I bought an old 87 capsule years ago to learn how to clean them.
Think like paint or paper restorer if you try to clean microphone capsules

 

[soliloqueen]

I managed to inspect a K47 capsule backplate recently. Here are my notes as a novice. Technical drafting is not my specialty, sorry.

The only differences between this and the actual sample are that I changed the front and side screws for a modern format, because I wanted to look into machining these. One detail I'm not 100% on is the diameter of the outer ring of holes. The thing is so damn small, it was hard to get this right. The differences in diameter between multiple rings I could get precisely by measuring more than one and dividing, but the outer ring to lip distance was tough. I've seen some vintage capsules that look like this, and some where all of the rings are spaced further outwards. Maybe someone else can chime in on this.

Edit. Why not? Here are the fusion360 and step files too.

Happy New Year!

 

[soliloqueen]

I don't think there's any accuracy in that, don't you think?
It seems they just stretch the membrane and go with it, I thought the process was a bit more precise and involved a measuring jig to measure the correct tension

Looking closer at his hand motions, he continues pushing the ring when it reaches the end tension and it doesn't move. To my eyes, it seems like the jig is designed to stop at the correct tension somehow

 

[kingkorg]

This is just insane what you were willing to share publicly, i applaud you for that! Thank you, and Happy New Year to all of you guys!

 

[soliloqueen]

This is just insane what you were willing to share publicly, i applaud you for that! Thank you, and Happy New Year to all of you guys!

Thanks, I worked in game dev for 15 years and do CG, so I have to have an eye for these kinds of proportions and design features.
Speaking of CG...

 

[JohnRoberts]

Yanking my chain over this is not a good idea...

JR

 

[soliloqueen]

Yanking my chain over this is not a good idea...

JR

Who is this directed at, is there anything we can do better?

 

[JohnRoberts]

Do less..... I have already had to respond to THREE reported post complaints about this one thread. And the "new years" ball hasn't dropped yet.

Think of me like the angry troll under bridge,,, don't make the troll even angrier.

We have finite rules about behavior. I will gladly banish any and all clear cut rule breakers, but hurt feeling are not in my wheelhouse to adjudicate easily.

I will revisit this tomorrow if you folks leave me alone, until then.

JR

 

[Tim Campbell]

I don't spend much time posting on here or RGO these days, but one thing I always see is Tim chiming in to anything Eric has to say.
Tim you're like a little girl. I'm so sick of your "fight" you keep perpetuating with Eric. Go do something else.
End of rant

Wave is Dave Wheeler who works for Heiserman Audio. I am unsure if this breaks the rules here but it is a bit sexist.

As far as I can see Eric hasn't posted on this forum for 4 years before this thread and I responded to a total of 2 of his posts so I am not entirely sure how this could be seen as a "fight".

Name calling seems more childish.

 

[abbey road d enfer]

To me, without any prior knowledge, wave is the offender. I have warned him; he is entitled to the opinion he expresses in his first sentence, but the second sentence is unacceptable.
I suggest all ad hominem ceases.

 

[Marik]

Neumann beadblasts their capsules as part of their deburring process.
I hope Marik joins in to reiterate his feelings about backplate flatness. Sound quality is not the only factor to consider here. Mechanical integrity is equally important. An uneven backplate will contribute to a membrane collapsing to a greater degree than a polished backplate.

Tim,

The backplate flatness and its surface finish are a bit different. For our backplates the 400 grit is a bit rough, but probably in other capsules depending on diaphragm/backplate spacing might work.

Our capsules designed to work with no DC to DC converters (and low current circuit), so the spacing is tighter. We finish lapping with 800 grit on Mitutoyo Grade AA granite plate with 0.00001” flatness. We do not polish our backplates, so the extra amount of air viscosity created by unpolished surface and tight spacing is a part of diaphragm damping.

Obviously, the lapping works only on backplates intended for use with spacers. With spacing machined into the backplate it won’t work. Right before Christmas we invested into media blasting system, so once I am back from my Holiday travel will start experimenting with it.

Best, M