U87 ALIEXPRESS

[ilikeit]

Hello everyone
I recently purchased this microphone from AliExpress style B34
https://fr.aliexpress.com/item/1005...st_main.5.6d735e5bN2cE6h&gatewayAdapt=glo2fra


It has a low pressure but the sound is not that catastrophic...
Especially for 45€...
Here are photos of the interior and the capsule.






Do you think we can improve it for little money?
Capacitors, etc etc

I also have a very loud resonant noise, I was told to perhaps do an assembly "in the air" of the 1G resistors

But I don't really know what that means ;-)


Thanks to you

 

[pucho812]

at that money, you would be hard pressed to not gut all of it and build a real mic into it.

 

[Ó Draighnáin]

Assembly is air means that the sensitive nodes are soldered/joined off the pcb floating in the air.

 

[Barry Hufker]

The link in the OP doesn't lead to the microphone shown.

 

[MicMaven]

Assembly is air means that the sensitive nodes are soldered/joined off the pcb floating in the air.

Do we tell him about "dead bug" and "point-to-point" and "free form" soldering now, or later in the course? I believe "Manhattan" style is not taught until Soldering 102.

James

 

[k brown]

I don't see anything assembled in air in that mic.

 

[pasarski]

Do we tell him about "dead bug" and "point-to-point" and "free form" soldering now, or later in the course? I believe "Manhattan" style is not taught until Soldering 102.

James

I also learned something new, that l you. I think I'm ready for the Soldering 102. I think my next build will be wild!

To the op: I bought a similar mic, though it had an electret capsule inside. That's funny, because the circuit is meant for externally polarized capsules. It even has a DC-DC converter board (the one with fewer components).

The loud resonant noise could come from the stiff looking capsule wires or the rigid capsule holder. Building the high z part in the air would probably make the mic even more microphonic and "resonant" if not executed with caution. Or is it "whining"? Maybe it's oscillating

You're not going to make it any better swapping capacitors. It's ok circuit imo (in a broad sense of ok). Just leave it as it is and maybe try different capsules. Or build a completely different circuit for fun or for an educational project. Maybe re-use the DC-DC board if you choose that route.

 

[pucho812]

if it were me, I would do the following.

Guts out, capsule out. In place, new capsule that is multi pattern. new guts include a subminiature tube. Due to space, output transformer can live in the PSU box which will have the correct power supply, pattern select and output transformer.

Then done, bobs your uncle.

 

[k brown]

if it were me, I would do the following.

Guts out, capsule out. In place, new capsule that is multi pattern. new guts include a subminiature tube. Due to space, output transformer can live in the PSU box which will have the correct power supply, pattern select and output transformer.

Then done, bobs your uncle.

. . . and empty's yer wallet.

 

[pucho812]

. . . and empty's yer wallet.

yes but the expensive bits are the metal work which are already done for you.

 

[StarTrucker]

I've heard foam on the body, especially where the shell meets the rails for the pcb reduces vibration and maybe your resonance problem.

usual suspects besides the capsule would be styroflex caps, I see those in Neumann upgrades and high end builds. Dunno how much difference they really make from personal experience, never built one without them.

 

[k brown]

A little surprised to see 2SK170 in a 'value' Chinese mic; wonder if it's genuine.

'Twer mine, I think the first things I'd change are the capsule leads for something much more supple, and making the 1G, FET and capsule junction in air / off the board (a lot of PC trace in that area). I'd get longer yoke mounting screws and put some grommets under the yoke. Everything else looks pretty OK, really, though I know nothing about the capsule.

Oh, and make hard connection from XLR leads to the board - don't see the value of that plug-in connector.

 

[pasarski]

if it were me, I would do the following.

Guts out, capsule out. In place, new capsule that is multi pattern. new guts include a subminiature tube. Due to space, output transformer can live in the PSU box which will have the correct power supply, pattern select and output transformer.

Then done, bobs your uncle.

That would be a mic worth $2795 I'm not sure they change the capsule though.

https://innertubeaudio.com/mini-87

 

[k brown]

That would be a mic worth $2795 I'm not sure they change the capsule though.

https://innertubeaudio.com/mini-87

And what exactly do they mean by "true Americans" . . . who are the false ones?

 

[pasarski]

And what exactly do they mean by "true Americans" . . . who are the false ones?

Probably a subject better suited for the secret board.

 

[Barry Hufker]

It's tongue in cheek...

 

[MicMaven]

if it were me, I would do the following.

Looking back ... as much as I have enjoyed building low cost microphones from bits, pieces and scrap parts ... I occasionally think I should have skipped all that and pooled my money to attain just one really good microphone, instead. After all, I am only one guy, with one voice. I wonder if I am the only one who contemplates selling the lot and getting something really good and calling it quits . . .

Um, er, never mind. I must be on the wrong forum . . .

James