aazaa

Neumann M49 internal parts in Beesneez body
« on: June 08, 2018, 02:56:34 PM »
I own 2 original Neumann M49 microphones. On the shelf original Neumann M49 internal parts complete with original trafo and capsule are waiting more than 20 years to find a new destination. So I was very happy to buy the Beesneez M49 body. Ben in his email: “I have a version of the m49 body that will fit perfectly the original neumann internals! All you will need to do is solder the pins for the cable.”

The original Neumann M7 capsule has been magnificently restored by Siegmund Thiersch.

The last few months I did experiments in the original Neumann mics with 9 different tubes using the M49b and M49c circuits. After solving some difficulties with ringing, the sound was superb. I ended with the Russian 6S6B-V/6С6Б-В tube but on noise there was still room for improvement.

Reading about the Josephson C725 mic I was tempted to go for a jfet/tube cascode circuit. It took a few weeks tweaking before I was entirely satisfied. Noise is gone now and, most important: the sound of the M49b tube circuit is still there. There is even some improvement in sound on very low levels.
Inspired by Josephson I decided to rebuild also completely the PSU adding a cascode fet/mosfet shuntregulator.

Now about the Beesneez body.
First impressions:
1. Wow, this body is very well build, finish is beautiful.
2. Most important difference is the basket. In the basket of the original Neumann there is visibly more space. Why not copy exactly??? Beesneez has the knowledge and the tools...

Then the dissapointment. I did install a rubber ring but saw soon that the Neumann internals could not enter in the Beesneez basket. Inside the basket the high quality has gone. The mesh inside the Beesneez body is not woven as it should be and it is only fixated on 4 points. As the situation is now, even if I could enter the Neumann parts, the sharp edges of the inner mesh plate would scratch the plastic cover.

In the Neumann basket the mesh inside is the same woven HQ mesh as the mesh outside. No sharp edges, it is entirely fixated and protected by a ring. Outside or inside, seen or not seen, always the same high Neumann level. Quality standard of 1956!

So my question to the forum: how can I best fixate the mesh plate inside? Epoxy glue? Solder?
I hope the Neumann internals will fit when the mesh plate is fixated and that there will be enough space left to cover the sharp edges.

Some pictures: (left: original Neumann basket, right: Beesneez basket)
https://www.dropbox.com/s/6ufxigvzj6nidk2/basket%201.jpg?dl=0
https://www.dropbox.com/s/oek643o5itj2r6o/basket%202.jpg?dl=0
https://www.dropbox.com/s/sz3c9enlebn1kio/beesneez-neumann.jpg?dl=0


« Last Edit: June 09, 2018, 04:39:45 AM by aazaa »


Moby

Re: Neumann M49 internal parts in Beesneez body
« Reply #1 on: June 08, 2018, 05:54:21 PM »
Hi aazaa, did you contact the manufacturer of the body? He is the active member of this forum. Maybe he can help and fix the issues you have with his product.
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com

aazaa

Re: Neumann M49 internal parts in Beesneez body
« Reply #2 on: June 09, 2018, 03:28:56 AM »
Yes Moby, I've sent an email with the pictures to Ben a few days ago to ask how to solve the problem. Until now no reaction. So I did start this thread in the hope to find a proper solution.

If I could manage to fix the basket and mount it without any damage to the plastic cover I would be very happy with the Beesneez body. It is the only way I see to bring the HQ Neumann parts again to life.  If we are not considering the barely attached flimsy inner mesh sheet I can say the body is very well constructed.

Only thing: I would have liked to have the same space inside the basket as in the original one.  I don't know how much influence there will be on the sound.

Really, Ben has the skills to build to Neumann standards. I don't understand his choice to change the basket. Better keep the original Neumann construction and dimensions.

Paul

« Last Edit: June 09, 2018, 05:15:42 AM by aazaa »

Murdock

Re: Neumann M49 internal parts in Beesneez body
« Reply #3 on: June 09, 2018, 05:36:33 AM »
Hmm, can you squeeze the inner mesh to the rim? It looks like it's to small.
If you can bend it, one last solution could be the use of solder paste... But you then would have to heat the whole headbasket quite a bit and I don't know how the finish reacts to this.  :-\

Moby

Re: Neumann M49 internal parts in Beesneez body
« Reply #4 on: June 09, 2018, 06:17:35 AM »
Hmm, can you squeeze the inner mesh to the rim? It looks like it's to small.
If you can bend it, one last solution could be the use of solder paste... But you then would have to heat the whole headbasket quite a bit and I don't know how the finish reacts to this.  :-\
We dont know how the manufacturer did the joints. Some (poor designed) use epoxy, some welding some solder paste. Whatever we suggest is wrong. Manufacturer has to respond. Dont get me wrong, but I see very clumsy handcraft job here. Maybe it's just your piece, I really have no experience with China made headbaskets.
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com

Re: Neumann M49 internal parts in Beesneez body
« Reply #5 on: June 09, 2018, 07:36:32 AM »
Hi All.

How are we?

That is a really easy problem to fix.

A few points first!

Our m49 body is the same internally to the earlier models.  Your one pictured with the stepped mesh ledge is a later model and this looks a little different internally.

Our mesh is also woven the same as it is the same size and cut directionally identically.

I am sorry the internal layer has become dislodged but it did not look this way when it left our factory. 

I would never have sent it to you looking this way as you sent me many many, many emails as to quality and the like. I even sent you pictures.

Ok lets get to the nitty gritty,

To fix it you will need to either send it back and let me do it or;

Take a small amount of solder paste, 

Hold the mesh in place with your finger but not to close to the joining place.  Apply a pin head or two of the paste, take a hot soldering iron and touch it to the paste for 5 seconds.  Once there is a smell,  remove the iron.  Wait 5 more seconds, and then release your pressure from your fingers holding the mesh in place.  Repeat this around the inner surround of the body and it will then look just like the neumann again.

It is a very simple issue that is very easily fixed.

Do not use too much solder paste as it will spill to the outer layers.  Less is more!

Let me know what you choose to do!

Cheers and sorry for your trouble.

Ben




Re: Neumann M49 internal parts in Beesneez body
« Reply #6 on: June 09, 2018, 07:38:17 AM »
We dont know how the manufacturer did the joints. Some (poor designed) use epoxy, some welding some solder paste. Whatever we suggest is wrong. Manufacturer has to respond. Dont get me wrong, but I see very clumsy handcraft job here. Maybe it's just your piece, I really have no experience with China made headbaskets.


Our joints are all solderpaste grafts.

And these are certainly not China made as you stated!

They are hand made by me,

Cheers.

Ben

aazaa

Re: Neumann M49 internal parts in Beesneez body
« Reply #7 on: June 09, 2018, 08:39:13 AM »
Ok Ben,

Glad to hear you. I was afraid to do the fixation in a wrong way.

I'll buy some solder paste and try to do the job myself. After all we are diy people.
Sending it up would cause too much costs and delay at customs.

I hope I manage to do a good job so that the plastic Neumann cover can be inserted without scratches. Do you think there is enough room left to add a small metal(?) protection ring to cover the sharp edges as pictured in my Neumann basket ?

It will take a few days before the solder paste is in. When the job is done I'll post pictures of the result.

Paul

Re: Neumann M49 internal parts in Beesneez body
« Reply #8 on: June 09, 2018, 08:54:45 AM »
Hi Paul.

The inner size is perfect and is exactly as the old Neumann was size wise.

Once the mesh is fixed around the body, it will not scratch the plastic of the neumann.

Thanks.

Ben

Moby

Re: Neumann M49 internal parts in Beesneez body
« Reply #9 on: June 09, 2018, 09:22:19 AM »

Our joints are all solderpaste grafts.

And these are certainly not China made as you stated!

They are hand made by me,

Cheers.

Ben
Dear Ben sorry, I thought it's made in China. Applologies
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com


aazaa

Re: Neumann M49 internal parts in Beesneez body
« Reply #10 on: June 11, 2018, 06:05:46 AM »
Hi Ben,

I did manage to solder the inner mesh. Not a very nice job but it is ok, no visible solder traces on the outside. There is just enough space for the neumann plastic cover to pass the mesh.
Alas, the space between the two bars inside is too narrow to let the neumann inner parts enter.

The 2 original Neumann's I own are both M49b. So I can see that the extra inner parts I have are earlier neumann inner parts. There is not yet a board to change the output impedance, the solder lips have only 2 lips, not 4.  If the dimensions of the Beesneez body are right I suppose it should be possible to enter the neumann internals.

In any case I do understand that neumann has chosen to improve the body for the M49b and M49C. There is more room inside, the way of finishing the mesh inside is much better. Did you choose to copy the early model because it is easier to build?

What to do now, Ben ? ? ?
Do you have a cover narrow enough on top to enter between the bars?
I would prefer not to cut pieces from the original plastic cover.

Paul

« Last Edit: June 11, 2018, 06:12:09 AM by aazaa »

Re: Neumann M49 internal parts in Beesneez body
« Reply #11 on: June 12, 2018, 08:06:35 PM »
Hi Paul, 

How much difference are we talking?

I am happy to make the adjustment for you.

Can you measure across the top of your plastic Isolator and let me know?

Thanks

Ben

aazaa

Re: Neumann M49 internal parts in Beesneez body
« Reply #12 on: June 13, 2018, 11:48:09 AM »
Hi Ben,

I measured 62,78mm (see pic below).
Thank you very much for your offer to make the adjustments. If you were living in Europe I wouldn't hesitate to send you the basket.
As said before customs are severe here and charge very much. I paid 185 euro extra taxes for import. So sending the basket would add too much costs (shipping + taxes). I think I could manage to slice myself a tiny bit of the bars. I hesitated to go for this option because I was afraid the basket would become too fragile.

So now I do consider following options:
1. Slice a bit of the bars. I think it would be possible to enter the original plastic isolator.
Downside:  as there is no extra room left on de sides, the internals will not be free to move. The damping of vibrations by the rubber underneath will not be very effective. The solution could be using the Rycote InVision USM-VB.
https://www.thomann.de/de/rycote_invision_usm_vb.htm

2. custom make a new isolator of 60mm.
I did a little research and found the round plastic box pictured below. It measures 60x35mm but the seller: "Please allow 1-3mm error due to manual measurement". So the 60mm is not guaranteed. As the china made boxes are very cheap I did place an order.
Shipping delay is +- 21 days.
Downside: 60mm is too narrow on bottom. I could slightly reduce the height (original is now +- 22,5mm).

Maybe this plastic box could be useful for other members of the forum looking for a M49 internal plexi dish.

Paul


« Last Edit: June 13, 2018, 02:56:05 PM by aazaa »

TillM

Re: Neumann M49 internal parts in Beesneez body
« Reply #13 on: June 13, 2018, 02:54:58 PM »
looks good, where did you buy them ?

Murdock

Re: Neumann M49 internal parts in Beesneez body
« Reply #14 on: June 13, 2018, 02:55:33 PM »
What kind of plastic is the Chinese box made of? The original is made out of perspex which is a kind of acryl/plexiglass . I ask, because it's quite important that the material has good dielectric properties as the capsule connections will touch the box...

I'm also on the search for a solution for this, as I want to build a replica. I found plexiglass tubes with the right outside diameter but the inside would have to be cut down. After that I would just glue a top disk on. Should work and look quite good.

But I'm also in contact with a manufacturer who can maybe build it according to original specs. I'm waiting on a quote. 

aazaa

Re: Neumann M49 internal parts in Beesneez body
« Reply #15 on: June 13, 2018, 03:25:12 PM »
looks good, where did you buy them ?

I did an order on :
https://www.aliexpress.com/item/Tops-Mini-Free-Ship-1-Pc-Wholesales-Hot-New-Round-Transparent-Beads-Display-Carrying-Case-Plastic/32660828921.html

You see, very cheap but I have to wait a couple of weeks before they will be in. I don't have further information now.

BUT
I just filed the bars inside the beesneez basket and the neumann internals can finally enter.  As there is no space left for the internals to move freely, I'll go for the Rycote shockmount. I did a first test and the neumann/beesneez microphone is doing fine from start.

So I'm happy !!!
Finally the neumann parts come to life.

If I had to build a copy I would use the Chinese box in the Beesneez body. It must be possible to cut the height to the right dimensions. With this box there is enough space in the Beesneez to give the inner parts free movement.

I intend to lower the capsule. Now it is too much near the top of the basket.
Conclusion: The Beesneez body is ok if you don't have to use the dimensions of the neumann m49b or m49c.

« Last Edit: June 14, 2018, 07:34:40 AM by aazaa »

aazaa

Re: Neumann M49 internal parts in Beesneez body
« Reply #16 on: July 11, 2018, 01:32:20 PM »
Chinese box is in. Very low quality. Don't buy it!!!


 

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