M7 AliExpress

[RuudNL]

These are the same it seems:

https://nl.aliexpress.com/item/1005004659042467.html
https://nl.aliexpress.com/item/1005004617115322.html
Main difference is the price...

(Did they solder the wire from the backplate directly to the capsule holder? Yuck!)

 

[qspart]

1.flac "FIN" m7 type capsule
2.flac "SCHOEPS" ck12 type capsule
3.flac "FIN" m7 type capsule
https://drive.google.com/drive/folders/1LNOJQWgK9DIR5A7nnR9cDLUlt8W4hjMp?usp=sharing

That m7 Sounds Pretty good .
Much Less Sibilant then schoeps ck12 .
It has this mellow typical m7 sound .
Would love to hear it against real m7 .
But again I don’t think there is such a thing like real m7 . As all of them aged differently and sounds different one from another.
What mic body /schematic did you used for this test?

 

[Drosselmeier]

 

[C12VR]

Anybody know if 3u is using these backplates?

 

[soliloqueen]

the backplates are visibly different even in the assembled capsules

 

[C12VR]

the backplates are visibly different even in the assembled capsules

are either accurate?

 

[soliloqueen]

are either accurate?

the 3u? insanely. here it is side by side with a real one from @tomas.borgstrom

they can differ a lot depending on when, but the only real difference between the two is that the 3u has wider slots for the glue. every other meaningful aspect is metrically identical. the capacitance gap cut into the plate, the diameter and depth of the blind holes, the diameter of the thru holes, and the placement of everything. they differ drastically only in diaphragm material, which is of course, quite important, but still. the 3u m7 is a crazy clone.

 

[Nen'O]

I went with Thierch STW7.
Since Jan 2023 they separated production for red line M7. It's now made by Rico, mr. Thierch son in low and long time employee.
After taxes and shipping it's not that more expensive than Chinese clone to get it here in Europe.

 

[craigmorris74]

the 3u? insanely. here it is side by side with a real one from @tomas.borgstrom
View attachment 104884
they can differ a lot depending on when, but the only real difference between the two is that the 3u has wider slots for the glue. every other meaningful aspect is metrically identical. the capacitance gap cut into the plate, the diameter and depth of the blind holes, the diameter of the thru holes, and the placement of everything. they differ drastically only in diaphragm material, which is of course, quite important, but still. the 3u m7 is a crazy clone.

What is the difference in diaphragm material? PET vs PVC?

 

[qspart]

These are the same it seems:

https://nl.aliexpress.com/item/1005004659042467.html
https://nl.aliexpress.com/item/1005004617115322.html
Main difference is the price...

(Did they solder the wire from the backplate directly to the capsule holder? Yuck!)

Hey .
I don’t understand if I am missing out on something, but how is that different then it’s done on u47 ? From photos I have seen cable on backplate is connected the same way.

 

[Nen'O]

Ive just installed 3U M7 capsule in multipatern tube mic.
It has sone issues with polar parter which i didn't have with previous capsule.
Do I need to connect grounding wire from capsule or not?
I already did psu zeners mod. R1 is now 124V.

Thanks

 

[Khron]

What is "grounding wire" supposed to mean?

"Multipattern tube mic" also kinda means nothing, since noone says all circuits are the same, so... we can't know what's going on there, or why you're not getting the results you were hoping for.

 

[Nen'O]

Hey @Khron , it's always nice to have you on board.
Microphone in question is Advance Audio CM67se or SYT-5 with modified circuit, so it's standards CCDA circuit with 9 polar patterns just like most Chinese tube mics.
Issue I have is when mic is in cardioid it works just like figure of 8, going further to omni mic looses all bass response 600Hz and down, when in figure of 8 no difference from cardioid both capsules are working.
There is differece in voicing in between front and back capsule just like in most dual diaphragm capsule. Ofaxis rejection is great and omni is well omni.
Maybe I messed up something ? In speck it says that it's design to run on 65-70v bias charge, I'm running it on around 60V. As well I assume ground wire from capsule has to be connected in all multi pattern mics?


Technical parameter:
Model m7
Sensitivity: -36dB ± 2dB
Pointing, multi pointing
Diaphragm transparency 25%
Overall dimensions: φ 32mm*6mm
Imported diaphragm: 6 micron polyester gold plated,
Frequency response: 20Hz~20KHz
Polarization voltage, 65-70
Power supply voltage: 48V
Capacitance: 70pf

 

[Khron]

Once again i must ask - what exactly does "ground wire from capsule" mean, in your view? The connection to the backplate, or....???

 

[Nen'O]

Should we call it black wire not connected to front or back of diaphragm I could be completely wrong calling it ground.

Anyway think I solved the mystery.
To get healthy signal when in Omni mic needs a lot more gain from the preamp, still significant bass roll of is noticeable.
Going from omni towards cardioid on PSU somewhere on half way, 2nd step, mic is in perfect cardioid, only front diaphragm is engaged and it sounds great. Cardioid setting on PSU is basically figure of 8 and both sides sounds smooth. In 8 setting front diaphragm sounds dull and back diaphragm harsh.

3U audio M7 capsule sounds great. Previous capsule in this mic was 35mm center terminated and it was very good capsule, too.

 

[Khron]

No, let's call it what it (most likely) is - backplate wire.

We still have no idea what's going on or how you have the capsule wires connected or anything, so... Pretty impossible to have any useful ideas / advice.

https://groupdiy.com/threads/apex-460-noise.53875/post-687821
See the schematic in that first post. If that little "-" sign near the capsule is supposed to mean the rear diaphragm, then that's connected to ground; backplate is connected to a fixed half-of-B+ voltage (~60v if your B+ is 120v) and to the capacitor going to the tube grid; the front diaphragm is connected to the pattern-control voltage.

(If i'm misinterpreting that "-" sign, then just reverse "front" and "rear".)