New u87 Body

[joulupukki]

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.

Actually, the measurements on Dany’s SW67 PCB look like they may fit.



What kind of switches would one use? Just standard mini toggle switches?

 

[AndyM]

What kind of switches would one use? Just standard mini toggle switches?

I will try slide switches, maybe capped with actuators or simply hidden behind the faux switches.
(Still waiting for Dany's PCBs)

 

[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

Just wanted to let yall know that I've tested the PCB today and while a sine wave generator feeding the input of the circuit give a sine on the output, and I can set the bias and etc ... hooking a capsule gives a loud (mains?) hum, and no sound so until further investigation, the PCB is still not validated
In touch

 

[jp8]

Just wanted to let yall know that I've tested the PCB today and while a sine wave generator feeding the input of the circuit give a sine on the output, and I can set the bias and etc ... hooking a capsule gives a loud (mains?) hum, and no sound so until further investigation, the PCB is still not validated
In touch

You'll need a Faraday cage to prevent the hum. High impedance input picks up mains hum. E.g. make a cage from chicken wire if it has to be transparant for audio. Or a cookie jar with XLR feedthroughs if it can be a closed cage. Connect the Faraday cage to the PCBA ground or mic body.

Jan

 

[thomasdf]

Thanks, I know about faraday cages and the role of the headbasket grounding in a mic design. The thing is I get only hum, no sound whatsoever behind it .. so I am suspecting a hookup problem somewhere, I'll do some further investigation and report back !

 

[thomasdf]

Removed the inductors I had on the output (old stock, vintage fetish haha) and now the mic works. So the PCB is verified, I guess
I'll report back after final assembly of my pair !

 

[chrispbass]

Anyone in the UK managed to order a HL-95 body from Aliexpress?

Tried today, and while it added to the cart, come checkout, it was a no go!

 

[Rob Flinn]

Anyone in the UK managed to order a HL-95 body from Aliexpress?

Tried today, and while it added to the cart, come checkout, it was a no go!

I ordered one a few months back with no issues.

 

[AndyM]

Anyone in the UK managed to order a HL-95 body from Aliexpress?

Tried today, and while it added to the cart, come checkout, it was a no go!

I managed to get mine via colisexpat as I couldn't order from Germany. A day before it arrived, I recieved a reply from the seller that he would have shipped directly as well. Took him 2 or 3 weeks to answer my initial question.

 

[chrispbass]

Thanks both. I've just sent a link to a friend to see if he has any issues.

 

[chrispbass]

Strangely, my friend has managed to order it for me! Very bizarre!!!

 

[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

Just finished my pair of u87i, they sound great ! PCB is verified

Arienne K87 matched capsules, UTM transformers

Cheers !

 

[JW]

Only seems to be the HL77 left these days on AliExpress. No HL95 for cheap. Wordsushi, is that resonance thing really down to the pcb's you used? I wish we could confirm what the heck that was about. And is it just from tapping the body, like not an issue if you don't tap the body while singing? Or is there more 100Hz boom when recording (while not tapping?)

Anyone else hear this with HL77, and dare I ask, a single pcb?

 

[micolas]

Only seems to be the HL77 left these days on AliExpress. No HL95 for cheap. Wordsushi, is that resonance thing really down to the pcb's you used? I wish we could confirm what the heck that was about. And is it just from tapping the body, like not an issue if you don't tap the body while singing? Or is there more 100Hz boom when recording (while not tapping?)

Anyone else hear this with HL77, and dare I ask, a single pcb?

I believe that the resonance of the HL-77 can be reduced using some materials. (For example, look at the Rode NT1 black).
And in the headbasket you can use a thin layer of varnish over the inner mesh.
IIRC @Wordsushi managed to dampen the parasitic resonances.

 

[micolas]

Cred că rezonanța lui HL-77 poate fi redusă folosind unele materiale. (De exemplu, uitați-vă la Rode NT1 negru).
Și în coșul de cap puteți folosi un strat subțire de lac peste plasa interioară.
IIRC @Wordsushi a reușit să atenueze rezonanțe parazitare.

@JW
The side pieces of foam press the tubular, cylindrical body of the microphone and dampen the vibrations.

 

[JW]

Thanks Micolas,

That's weird. The rails shouldn't be touching the shell/sleeve anyway. ??? Then the pathway to the rails would be through the bottom bell or headbasket. Just seems like the foam would make more points of contact. This is assuming vibration of the pcb is causing this resonance, rather than the HL77 body? Why not just try mounting the board with some rubber washers between?

Edit: Varnishing the headbasket seems to imply some other resonance due to headbasket material?

 

[micolas]

Thanks Micolas,

That's weird. The rails shouldn't be touching the shell/sleeve anyway. ??? Then the pathway to the rails would be through the bottom bell or headbasket. Just seems like the foam would make more points of contact. This is assuming vibration of the pcb is causing this resonance, rather than the HL77 body? Why not just try mounting the board with some rubber washers between?

Edit: Varnishing the headbasket seems to imply some other resonance due to headbasket material?

Forget the pcb. The cylindrical body resonates, like a church organ pipe, or like the body of a wind instrument. The foam pieces are to dampen the resonance of the body. With or without pcb.
Headbasket has a resonance of its own. Metal transmits vibrations very well. If I use a material to cover the mesh (even partially so as not to change the internal microacoustics) with a thin layer (non-metallic) I will reduce the resonance.