New u87 Body

[Khron]

Different cap values, different resistors value... What am I missing ? Is the ORS87 based on the U87i ?

And just how much difference (and in what direction) would you imagine the alternate values make?

While the idea is indeed based on the original U87 circuit, at least my version has a more... dare i call it, "sane" BOM (bill-of-materials). No point in needing 10-15 different component values, when five will do just as well (if not better).

 

[thomasdf]

Ok, thanks for clearing it up. I am not saying one is better than the other. But I would like to get closer to the original design here... and I already have almost all the parts, vintage NOS capacitors to play with, etc.

I am no microphone wizard like you and some guys around here, but I know what I like in the OG, and would like to give it a shot

 

[AndyM]

Agggghhh! I feel like we’re so close to really accurate bodies, I wish these had working switches.

Maybe I’ll have to be the one to figure this out. I wonder if something could be 3d printed and use magnets to activate a reed switch…

Was wondering if you have figured out a way in the meantime?

 

[OneRoomStudio]

Well, there is this U87 body kit now. I asked the seller if it includes switches, but I haven't heard back. It would be great if this was a viable option!
https://www.aliexpress.us/item/3256807592342089.html

 

[RuudNL]

It looks like you have to add the magnets and the reed contacts yourself. Only the mechanical parts.

 

[OneRoomStudio]

It looks like you have to add the magnets and the reed contacts yourself. Only the mechanical parts.

I think you’re right. I’m mostly interested to see if the switch actuators are included.

 

[thomasdf]

At some point a random guy offered this kit for around 300usd on the forum, and the post got deleted.
I think 211 usd is still a bit on the expensive side, and from what I see the PCB mounting is aimed at the AI version ?

Anyways, I have been working on a U87i PCB to fit the body discussed in the thread here, with the idea to make the gerbers available here for free, for the community and non profit use.

Stay tuned

 

[kingkorg]

IMHO the best part about that body is that one could interchange circuits and capsules.

 

[Dylan W]

One detail that might be worth verifying is to make sure the plastic circle (that holds the interconnect pins for the removable head) is made of a material with similar electrical properties as the original.

I recall Oliver Archut writing that, in the Lucas mics, there were issues with acrylic boards being laser cut vs water cut and that affecting the resistance/isolation. Just a thought, since it's an extremely high-impedance node.

 

[soliloqueen]

This is not the same body as the fake u87. It's a similar body with the same plastic parts. Can't verify that the performance is as good

 

[thomasdf]

Hi all

So I started with schematics down here, to kicad, to this gerber
Untested yet but the boards turned out great from JLCPCB
Only mistake is the mounting holes are approx 1mm too close to each other, so I have to very lightly bend the mounting rails for the holes to line up. The body can still be assembled without problem.

I offer no guarantee, no help with the build etc. It is pretty much 1:1 the orig schematic and there are plenty of info around.

In case you don't want to use them L1 and L2 must be replaced by a straight wire, and C21 and C22 omitted.

Rename the TXT to ZIP to get the gerber

High Z teflon pins are meant to be Mouser no 534-11218
There are different options for C7, orig is tant but some like to mount bigger caps.

I am slowly starting to build a cardiod only pair of these, I'll report back... If someone else goes first, let me/us know I'll use a pair of UTM transformers and I'd like to use a pair of Arienne's cardiod K87 capsules when available

Cheers