U87 (Revision A) in BM800 microphone donor body

[Khron]

4. I have isolated the rails with electrical tape, and I used m1.6 Screws to attach the PCB's without touching anything.

Why would you NOT want the ground pads of the PCB connected to the mic chassis?

 

[RBeTT]

Why would you NOT want the ground pads of the PCB connected to the mic chassis?

The holes of the rails to attach the PCB don't align with the PCB, so I use screws from one side to another [18mm] with nuts and washers which press the PCB against the rail to secure them. Since it isn't properly secure via the holes and might touch other components, I decided to isolate it from the rails and use the ground PCB hole to connect via pin1 [ground].

Isn't that a good idea?

 

[Khron]

The holes of the rails to attach the PCB don't align with the PCB

Are those side-rails cast, or sheet metal? If they're sheet, bend them so the holes line up with the PCB's.

 

[RuudNL]

Usually the chassis of these cheap Chinese microphones are made of die-cast metal.

 

[mihi_fuchs]

Hi @mihi_fuchs

Sorry for the late reply, it has been crazy weeks...but I am finally back to answering properly your very kind reply


I'm a bit confused about how to do it. Will I use the studio monitors to produce the sine wave generator? If so, do I have to open the mic every time to adjust the trimmer and do the test again?

I have confirmed that the PAD and transformer wiring are where they should be. We both used a 3u Audio transformer, too, so I just followed the pictures.

The capsule it's new and right off the box. Since it's backplate independent, I have attached 2 black wiring accordingly to the building guide.

I don't know how to answer you. Can you be specific about where and what should I look for? I'm still a bit fresh on this new world...Sorry!


INFO | QUESTIONS

1. The mic body it's conical and not cylinder, I can feel a bit of no being centered with the bottom screw, can that be a problem? Perhaps if the tall WIMA components touch it? ;

2. Since I didn't know how to calibrate properly, I adjusted to 60v and 10.5v on RV24 and RV10, respectively.

3. Via BOM, it comes 2x as Turrets, which I don't know why. On my first U87 build, I had a turret on J3 [front capsule wiring] like the @Wordsushi had done it, which helped a lot with the hissing noise. Should I keep it or not?

4. I have isolated the rails with electrical tape, and I used m1.6 Screws to attach the PCB's without touching anything.

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Here are the build pics, Sound spectrum via EQ and the sound recording I made in my last test.

20Nov24 Sound Test | AUDIO SAMPLE [Dropbox]

View attachment 140328

View attachment 140321View attachment 140322
View attachment 140323View attachment 140324
View attachment 140325


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As always I appreciate feedback, time, and your patience.

Best Regards,

RB

Hi Ruben,

hope everything is fine?

Sorry to hear you still have issues. Components touching the rails may be a very good explanation. However, one thing caught my eye, when looking at the pics:
If I get your wiring right, you used the "Messeingang" for grounding your basket? If that's right, you have used the wrong pad. So if you have another ground connection from the head basket to GND, you maybe simply short R4. Maybe just solder the wire in the pic below to the square pad?

Best regards,
Michael



P.S.: I just double checked - the numbering on the PCB regarding the Messeingang is wrong. 1 is the square pad, 2 the round pad. My apologies. Was not your mistake but my wrong numbering. Apologies for that.