Neumann M49 Clone : Build Thread Puck Style (TLM49 Conversion To M49 b-c)

[Cgaines]

sorted the issue on one, was my fault wiring in the transformer!!, the M49c one still buzzes a little so will look at next week!!!

regards

Spence.

Did you ever find a solution? I have the same issue, and can’t seem to figure it out. I’m also building a 49c?

 

[Spencerleehorton]

Yeah pretty sure it was a psu gnd issue

 

[Delta Sigma]

Hey guys, I just finished my build and I’ve got a ground buzz coming through. The microphone works, sounds great and doesn’t have any other noise, just a ground buzz. All of the grounding seems to check out and I have continuity throughout everything. I’ve searched through this thread to see if anyone has had a similar issue, but couldn’t find any posts. Does anyone have any ideas on what I should check? I also ran it through an isolation box to see if that would get rid of the buzz, but it did not. I’m kind of stumped. Also, once I kill the power to the PSU, and the capacitors are still charged, The buzz goes away in the mic sounds fantastic.

Put it in the body and try again.

 

[Cgaines]

Put it in the body and try again.

Well, I was hoping it would be that simple but it wasn’t… anymore ideas

 

[Cgaines]

Strange part about the noise is I have continuity everywhere I check. I can put a probe on the ground pin of the IEC and probe all way through the PSU up the mic and it all checks out.

 

[Delta Sigma]

Not sure what the noise is that you are referring to. What I heard in the video, was a capsule without any screening. It definitely shouldn't sound like that in its mic body.

Headbasket, body tube, and bottom bell all have continuity?

 

[Cgaines]

Not sure what the noise is that you are referring to. What I heard in the video, was a capsule without any screening. It definitely shouldn't sound like that in its mic body.

Headbasket, body tube, and bottom bell all have continuity?

Yes, I completely assembled the mic and checked continuity on all those places you mentioned, and there’s still a noise. That’s why I’m so perplexed. I actually bought enough to make a pair of these mics, so I assembled the other one, with PSU and I have the same noise. So I’m obviously doing something incorrectly in the build process. I just haven’t figured out what I’m doing incorrectly. By the way, thanks for taking some time to help with this.

 

[TLRT]

this is the same body as ami and chunger but with custom internals, that's all

Yes the basket is ok quality that is the important part. We had some progress ín the meantime:

 

[GeorgeToledo]

this is the same body as ami and chunger but with custom internals, that's all

The AMI mic bodies have different dimensions than what is pictured, unless I’m looking at the wrong picture or AMI changed bodies. The bottom bell sizing is different.

 

[soliloqueen]

The AMI mic bodies have different dimensions than what is pictured, unless I’m looking at the wrong picture or AMI changed bodies. The bottom bell sizing is different.

This one's got swappable bell bottoms, there are a couple of them iirc

 

[Delta Sigma]

Yes, I completely assembled the mic and checked continuity on all those places you mentioned, and there’s still a noise. That’s why I’m so perplexed. I actually bought enough to make a pair of these mics, so I assembled the other one, with PSU and I have the same noise. So I’m obviously doing something incorrectly in the build process. I just haven’t figured out what I’m doing incorrectly. By the way, thanks for taking some time to help with this.

This may be, but all I could hear in the video is interference. If you have it assembled, and record a video, it should sound different. It may be that you have a ground loop in the power supply. You might be hearing the ground loop with and without the headbasket & body, but I couldn't tell from the video without the headbasket.

My grounding philosophy is to terminate the shield to the mic body as close to the connector as possible with as short of a wire as possible. I usually attach with small ring terminal where the rails connect to the bottom bell. I always connect 0V to the mic body, sometimes at the same spot where the shield terminates. Inside the power supply, the shield again terminates to the chassis as close to the connector as possible. I scrape paint around the connector mount hole and terminate there. I only have one connection from PCB 0V to the chassis inside the power supply, usually at the same point as the shield.