FEELER: M49/50 Bodies

Hey everyone,

Quick update, I hope to have the first prototype in my hands this week. I have a tracking number and everything! I want to take some pictures myself once I have it in my hands. I will post them once I have it.

Eric

I am going to keep the Santa hat on my avatar, ha ha!

Ho Ho Ho

add me to the list for at least one!

hi eric,
i like where this is going and i'd be interested in at least one body at the price point suggested earlier.  i do have a point i'd like to bring up that was also brought up in the C12 thread by Jess Jackson regarding the top of the grill looking wider than the bottom and chunger's reply regarding the way the grill is attached to the mounting ring : http://www.groupdiy.com/microphones/%28feeler%29-c12-clone-project/400/
it looks like the same issue can be seen in your M49/50 prototype or maybe i'm just seeing it at a bad angle.  aesthetically it would be more accurate and pleasing if the headbasket where less bulbous on top and vertically straight / linear.  is this something that can be addressed at this stage?
i am in awe of your efforts with your capsules and now with this body so i hope you do not regard this post in a bad light.  it is merely a critical comment.
thank you for doing this!
kindest regards,
grant

I modelled this design after several views and measurements off of the real thing. When myself or Eric gets the prototype we can double check these dimensions.

When the outer trim ring is in place and the headbasket is soldered together, I bet the appearance of the mesh will change a little.

Also, I am not sure what "seating depth" the mesh is in at in this picture. Again we can check this.

riggler said:

Yes, these will fit Dan's PCBs. I have made several spheres after getting the process down. It's was hard initially but now I have the process down and made a jig, etc.

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I was being serious. I would if its ok Like to see the back of your capsule sphere and if you could share what capsule that you have mounted in it. The reason I am curious is the sphere you have machined is impressive and looks very close to a workable solution. But the capsule on the other hand is what really completes the M50 sonic character. The rejection rate of these capsule-sphere assemblies is what led to the mic being discontinued.

I have never seen one with its grill off and with what it would mean to any owner if I broke there M50 I have never even considered opening one. If you have noticed pics are rare on the net.

I believe there is a vent hole that is in the back of the M50 Acrylic sphere of old and the new TLM50 sphere is hollow. I believe this is for significant sonic reasons although I don't know what they are? Also the original M50 nickel capsule was surrounded by what I think is a silver plated transition ring whos tolerence was strict as to its relationship to the sphere horizon and the capsule ring. The TLM50 does not have this.

I also noted that the capsule in the photo has mesh and there is a what looks like an acoustic delay plate. I wonder if this is the right choice as I have been looking for a supply of omni medium plateless capsules for a while maybe I am waisting my time and this is not a problem.

Looking forward to you guys getting the bodies sorted. I have a guy with a CNC machine who is going to help me machine some prototype spheres once I decide on a capsule. Keep forum posted as to progress.

Hi Pip, been super busy, sorry I did not reply. I am heading to an orchestra recording right now, but when home I will take more pics and stuff!

Capsules are KK83. I made a jig to drill the 40mm spheres. I made a slurry of water and baking soda to keep it cool when drilling. I cut down until about 2mm away, then would test fit until just right. Not perfect, but cheaper than CNC ha ha....

Original sphere has a hole in the back that the backplate screw would go through. So I let my lead come through the hole, and I will plug the void with a bit of rubber.

Whole thing mounts to a rubber stud I got from the hardware store. soldered a brass lead tab for the diaphragm connection.
There is a threaded hole I drilled into the capsule receiving tube my capsules came with. DIY -- used what I had here. I don't know if the mesh and baffle REALLY will matter that much. Will have to see how these sound!

Hey all,

Just a quick update. So I recieved the body and already sent it back for some changes!! I wasnt very pleased with the headbasket construction. It was a bit dissapointing. He promissed me the next go would be perfect so I am hopefull! Its already back in his hands so the turn around shouldn be to bad.

More to come!!

Eric

riggler said:

Capsules are KK50. I made a jig to drill the 40mm spheres. I made a slurry of water and baking soda to keep it cool when drilling. I cut down until about 2mm away, then would test fit until just right. Not perfect, but cheaper than CNC ha ha....

Original sphere has a hole in the back that the backplate screw would go through. So I let my lead come through the hole, and I will plug the void with a bit of rubber.

Whole thing mounts to a rubber stud I got from the hardware store. soldered a brass lead tab for the diaphragm connection.
There is a threaded hole I drilled into the capsule receiving tube my capsules came with. DIY -- used what I had here. I don't know if the mesh and baffle REALLY will matter that much. Will have to see how these sound!

Click to expand...

Pretty cool. Since I last replied I have been doing a lot of research into these assemblies and I have to say it is a daunting task for sure.

Check this out:

http://www.saturn-sound.com/Curio's/neumann's%20kk50%20capsule%20assembly.htm

I don't know if this is for here as it is away from the bodies issue which we are all combining our thought energies if nothing more to help move forward. But I have some thoughts.

I have to say I am really beginning to wonder if I can machine Acrylic to these tolerances. I am starting to contemplate Delrin or even CPVC.

I know everyone is a critic and I appologize for joining the throngs but I am not sure that a gap no matter how small between the capsule ring and the sphere is going to result in the proper attenuation factor of the high frequencies. Because the only thing at work here is friction and frequency power relationships. I would worry that any shelf or cavity would greatly slow the highs beyond what is wanted  and result in an undesireable delay and resulting phase shift increases. But that being said you are further along than I am to a working prototype.

The capsule is a KK50 or a KM series? because I do not remember seeing any pics with a rounded ring edge but almost all the KM series capsules I have seen have an edge similar to that and I know that they are all very close to the  later KK50 capsule. It will probably work fine. The last KK50 capsule offered did have a diaphragm disk and mesh.

Awesome job can't wait to hear some samples.

Typo Pip!!! These are KK83.... Oops. I have looked at the Saturn Sound site and there is a lot of information there on these capsules.

I think diffraction from the outermost ring edge of the capsule is the bigger issue here. I am going to fill the gap with a small amount of silicone placed with a toothpick. Keeping the acrylic cool is the hard part, which is why I did the water / baking soda thing!

This thread just keeps getting cooler, I never knew about the acrylic sphere on the M50. I'm tempted to make an acrylic mold now or heck even try it with a 3d printer. Here's an internet find many of you probably have already seen but I thought it was interesting, especially the notes on the different revisions of the M50 capsule...

http://recordinghacks.com/microphones/Neumann/M-50

Another quick update,

The improved prototype should be in my hands this week... If everything looks good I will post some pictures! It's close I swear 

Eric

did your finger touched this new Proto  ,

Best,
DAn,

Ok everyone,

The prototype is completed and I am ready to take orders. I am going to get a Paypal account started soon and will start taking orders!
Thanks,
Eric

pics??
regards
Bernd

bernbrue said:

pics??
regards
Bernd

Click to expand...

Pics wanted

US beats UK by a nose length.

Hey, don´t forget Germany! 
regards
Bernd