New u87 Body

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
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).
 
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
 
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
 
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.
 
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
 

Attachments

  • U87-schematic.png
    U87-schematic.png
    95.1 KB
  • 87i.png
    87i.png
    197.5 KB
  • u87gerber.txt
    109.8 KB
  • 87iPcb.png
    87iPcb.png
    215.8 KB
HL-95 Body just arrived. Here it is next to a TLM-67
The HL-95 so far does not exhibit the same resonant ringing sound that the HL-77 has. The body shell is fairly heavy brass, so it has some heft. The black "rings" around the bottom cap and at the faux switch level are just thin plain black tape that has been applied a bit sloppily.
And as seen in the previously posted internal photos, the rails are a bit closer together than the HL-77 so dropping in a PCB like the Fuchs or the Bouchard 87 will require some finessing, so while I think it's a pretty cool body for $60 delivered from Aliexpress, it's not a "plug and play" type of solution like other bodies.
What is the width of the 3 openings/windows for the switches?
 
Hi everyone,
my HL-95 has finally arrived. Since you couldn't order from Germany I had it shipped to Colisexpat in Spain and forward it to me. This actually worked pretty well.
As mentioned before, the black tape is applied rather sloppily.
20241028_133425.jpg
Luckily it seems forgiving and will stick again when applied more carefully.
20241029_171438.jpg
The sticker for the faux LC and pad switches are kind of funny. 🤔

20241028_133232.jpg
20241028_133222.jpg
The tab for the pattern switch seemed a bit bent. So I tried to bend it back. Bad idea - crack! 😳
20241028_133207.jpg
Besides that it seems to be a well made body.
 
I received mine last week too. The black sticker stripes are bound to fall off and the cardioid sticker is crooked just like what you're showing here. If anyone ever designs a PCB for some actual switches that'd work in this body, I'd be interested. I built the Fuchs U87A circuit in this mic and it's sounding great, but it'd be nice to have the switches accessible instead of needing to open it up and use jumpers.
 
Send me a body and I'll see what i can do 😅
I used some epoxy glue to stick some sub miniature pcb mount switches to the underside of the capsule mounting plate for the filter & pad. I used a small bit of perforated pcb to bolt the pattern switch to the other side of the plate, I couldn't glue it because I think there was a screw that I needed to get to in the way. However if there was a pcb available for this task I would probably buy one.
 
Back
Top