[Help} U87 from Aliexpress

[hazki]

I don't have any clue about circuit boards and all the technical stuff so I would like to ask what these are all about.
I found a fake U87 from a chinese manufacturer and this is what the inside looks like:
main

2nd

original video where I got the screenshots -

I just wanna ask what those are and what they do? and is it better than bm800?

 

[Drosselmeier]

The presence of a dc-dc converter (2-nd picture) hints at a large capsule which is not in BM800

 

[kingkorg]

In the video it seems like electret capsule but larger then bm800 one. It will probably sound somewhat better than bm800, but not considerably.

 

[Drosselmeier]

i thought so too, but in this case you can buy and put ldc later
maybe that was chinese manufacturer's genius idea)

 

[Icantthinkofaname]

i thought so too, but in this case you can buy and put ldc later
maybe that was chinese manufacturer's genius idea)

Since the video review suggests it comes with the XLR to 3.5mm cable to plug into a sound card maybe they also need the converter for it to function properly since a sound card likely gives between 1.5v and 5v. I'm assuming the capsule is designed for 9 or 10v if it's a larger electret. But I'm just guessing.

 

[Drosselmeier]

Since the video review suggests it comes with the XLR to 3.5mm cable to plug into a sound card maybe they also need the converter for it to function properly since a sound card likely gives between 1.5v and 5v. I'm assuming the capsule is designed for 9 or 10v if it's a larger electret. But I'm just guessing.

No. This dc-dc converter is most likely +6V-12V to +60V
to polarize the large microphone capsule(not electret).

 

[hazki]

if I remember correctly, something like this was used as the capsule

- https://www.aliexpress.com/i/4000262163811.html

would a 34mm capsule work on this mic too?

 

[Drosselmeier]

Yes sure. Now the capsule is connected by one contact to input(FET gate), the other to the ground (red line). This is an electret connection schematic. LDS must be connected to the input and output of the DC-DC converter (green line). Check whether the power is supplied to the board with the inscription LH100B.

 

[hazki]

Yes sure. Now the capsule is connected by one contact to input(FET gate), the other to the ground (red line). This is an electret connection schematic. LDS must be connected to the input and output of the DC-DC converter (green line). Check whether the power is supplied to the board with the inscription LH100B.
View attachment 95884

thank you so much! the world of microphones is a very interesting one.

 

[abbey road d enfer]

The thick-film 1G resistor connected directly to the FET is a dead ringer for a non-FET capsule.

 

[MicMaven]

Amazon reports the item costs around $30 with these specifications - I suspect it works like the BM-800 in that it is designed to work with either 10v bias power from a computer sound card, or 48v phantom voltage - but I find it odd it appears to employ a bias voltage circuit board like what is used on true condensers, but it may only appear to be that sort of board - as it may have a permanantly charged electret capsule ... nothing definite - just more clues.

Auntoo Product model: for U87
Type of microphone: Condenser microphone
Directivity: Heart-shaped pointing
Sound : 26 mm
Max.SPL: 135dB(at1kHz less than or equal to 1%T.H.D)
Frequency response 25Hz-18kHz
Signal to noise ratio: S/N:78 db
Sensitivity: -38dB +/- 2dB
Output impedance: 680 ohm65%(0dB=1V/Padl1KHz)
Load impedance: greater or equal to 1000 ohm
Current consumption 3.1MA
Power supply mode: 5V148V
Output interface: XLR interface
Colour: silver
Material: aluminum alloy
Size: 23 x 23 x 10CM

Package Contents:
1 x Metal Microphone
1 x Plastic Shock Mount
1 x Audio Cable
1 x Windproof Cotton

 

[Icantthinkofaname]

if I remember correctly, something like this was used as the capsule
View attachment 95880
- https://www.aliexpress.com/i/4000262163811.html

would a 34mm capsule work on this mic too?

If that's the capsule I think it is, you might not want to replace it, Kingkorg has great things to say about it.

 

[MicMaven]

If that's the capsule I think it is, you might not want to replace it,
___________________________________________________________________
Um ... er ... I agree. I repaired a broken Behringer C-1 with an OPA Alice board and a capsule that looks like that one - actually it looks better in person, but it was sold using the same photos - and I was very pleased with the result. Good luck. James

 

[kingkorg]

If that's the capsule I think it is, you might not want to replace it, Kingkorg has great things to say about it.

Funny thing about that capsule is that it's very, very close to the stock response of the Slate VMS ML-1 modeling microphone. So not that similar to the capsule in ML-1 but very similar to the response of the whole ML-1 mic.

It is not 100% spot on but it can easily be used as a backup, or simple inexpensive anternative with the Slate VMS software. The difference between this capsule and ML-1 is smaller than the variation in most of those mics VMS tries to emulate.

It is most certainly closer than ML-2 sdc Slate advertises to be basically interchangeable with ML-1.

Update: Im just babbling for no reason, here are the two. The purple is the Slate ML-1.

 

[Icantthinkofaname]

Funny thing about that capsule is that it's very, very close to the stock response of the Slate VMS ML-1 modeling microphone. So not that similar to the capsule in ML-1 but very similar to the response of the whole ML-1 mic.

It is not 100% spot on but it can easily be used as a backup, or simple inexpensive anternative with the Slate VMS software. The difference between this capsule and ML-1 is smaller than the variation in most of those mics VMS tries to emulate.

It is most certainly closer than ML-2 sdc Slate advertises to be basically interchangeable with ML-1.

Update: Im just babbling for no reason, here are the two. The purple is the Slate ML-1.

Is it the one that reminds you somewhat of the CK12, or am I thinking of a different SDC capsule?

 

[kingkorg]

Yes that one. It's the one that has quite similar construction to the latest ck12 capsules used in the c414 mics, not really to the original.