OPEN SOURCE DIY Mic Project - ORS 87 - Stripped Down u87

[soliloqueen]

Normal grounding stuff. Tie pin1 to the chassis via the little notch thing on the front of the XLR jack. I'll definitely take a look at it and maybe the inside of the xlr barrel on the body has paint in it or the screw hole that holds the xlr jack in place? I'll dig around inside to see what the grounding situation is. Thanks!!

how is the board grounded? is there a pin1 header on the board?

 

[micolas]

It looks like a ground loop or imperfect connection between the body parts and the PCB GND.
*Is the fan on?

 

[Khron]

Paint covering the top / bottom edges of the body tube? Headbasket not making proper contact with the chassis?

 

[micolas]

Paint covering the top / bottom edges of the body tube? Headbasket not making proper contact with the chassis?

That's what I was thinking
Body parts/head basket/meshes, oxidized, dirty
*Good protection against RF interference is not achieved

 

[micolas]

In such situations, to find out if the disturbances are electromagnetically induced due to the shielding (Faraday cage) or electrically (for example through the xlr cable/connector), I completely put the microphone in a stainless steel kitchen pan, which I connect to the GND of the cable XLR.
Or in a large empty metal can.

 

[micolas]

View attachment 129550
Took advantage of my Aliexpress getting delivered on a holiday and finished my first attempt at a dual output STEREO ORS87
View attachment 129551
And this is me just a quick stereo ambience test of me pushing stuff around on my desktop with the mic hanging over top.
View attachment 129552
And shaking a plastic box full of small mic screws around the mic.

@Wordsushi
Stereo ORS87 looks beastly!
I really like a lot.
Sounds realistic! In some spatial setups in conjunction with other microphones it would do multidimensional wonders!

 

[Wordsushi]

@Wordsushi
Stereo ORS87 looks beastly!
I really like a lot.
Sounds realistic! In some spatial setups in conjunction with other microphones it would do multidimensional wonders!

Thank you! Taking it out of an 87 style body and putting it into a round headbasket body made a huge difference. I'm very pleased with this one. I'm going to have to make some plans to use it. Maybe I'll have to do some of that stupid ASMR stuff with it.

The Nano however is dead. I had tried a different 103 style body shell and had the same issue.

Arienne gave me some pointers after identifying the noise as 2.4ghz wifi, which makes sense because my booth is not far from the router (which can't be moved).
I had XLR 1 connected to the ground plane on the board instead of just to the body, which she said was causing a loop. So, I altered the PCB and rewired it and I must have borked it somewhere because now I have no signal and 48v reading everywhere. I'm at a loss as to why this one and not the other one or the larger body ORS87s I've built, so I'm just going to chalk this one up as a loss. I've started stripping the board for the parts to rebuild another one the way I did the first one again. Live and learn. At least I know now I like this combination of Bai Fei Li k87 capsule and Ali T-13 transformer on this one.

 

[micolas]

Nano however is dead. I had tried a different 103 style body shell and had the same issue.

Arienne gave me some pointers after identifying the noise as 2.4ghz wifi, which makes sense because my booth is not far from the router (which can't be moved).
I had XLR 1 connected to the ground plane on the board instead of just to the body, which she said was causing a loop. So, I altered the PCB and rewired it and I must have borked it somewhere because now I have no signal and 48v reading everywhere. I'm at a loss as to why this one and not the other one or the larger body ORS87s I've built, so I'm just going to chalk this one up as a loss. I've started stripping the board for the parts to rebuild another one the way I did the first one again. Live and learn.

At least I know now I like this combination of Bai Fei Li k87 capsule and Ali T-13 transformer on this one.

I hope that in the end you will identify the real cause of the problems related to the interference produced by the wi-fi systems and ways to solve them. It is a broader topic, of general interest, in the future it will be an increasing challenge. I think the topic deserves a separate dedicated thread. We practically live in an ocean of electromagnetic radiation of many kinds, frequencies, intensities, etc.

The capsule from the BeiFeiLi microphone used with good results, could it be one of the ones sold separately on Ali..? You are in the best position to identify it.
Isn't it more advantageous to buy only the capsule and not the whole microphone? We have many good bodies and components waiting to be used.

 

[cello4u]

Looking for a step by step, or video of assembly of ORS board? So far I've been able to put circuits and capsules into a microphone, but full on assembly I need some help. The breadboard pic with blue and red wiring looks super helpful, but I feel I could use a tutorial.

 

[micolas]

Looking for a step by step, or video of assembly of ORS board? So far I've been able to put circuits and capsules into a microphone, but full on assembly I need some help. The breadboard pic with blue and red wiring looks super helpful, but I feel I could use a tutorial.

Welcome to the group!
Have you considered buying a PCB to populate with components(it would be easier to do) or have you not yet decided which way to go?
Perfboard, breadboard,point-to-point: very cheap but more complicated.Unfortunately there is no video tutorial for building ORS87, whichever version you choose.

 

[cello4u]

Welcome to the group!
Have you considered buying a PCB to populate with components(it would be easier to do) or have you not yet decided which way to go?
Perfboard, breadboard,point-to-point: very cheap but more complicated.Unfortunately there is no video tutorial for building ORS87, whichever version you choose.

I have the ORS 87 v1.1 PCB

 

[Khron]

I have the ORS 87 v1.1 PCB

https://groupdiy.com/threads/open-source-diy-mic-project-ors-87-stripped-down-u87.86814/post-1144040

That should be a pretty comprehensive bill-of-materials. Maybe attach a photo of the board so we can verify the component designators vs the values? I'm not gonna spend even more time digging through the rest of this thread for that

 

[micolas]

I have the ORS 87 v1.1 PCB

Excellent. I assume that you have already purchased all the electronic components, the capsule and its support, transformer, microphone body, other parts, etc.
Already some members who have used this PCB have posted pictures, or will surely be kind enough to post more, detailed, relevant, with information, directions. Including jFET BIAS tuning methods.
Be sure to read the entire thread from the beginning and other threads about the U87.
Arm yourself with patience and perseverance. Good luck!

 

[micolas]

The breadboard pic with blue and red wiring looks super helpful, but I feel I could use a tutorial.

I have a puzzle: why do you mind the drawing of PCB v1.1, red and blue paths/traces? Ignore them, they are on the PCB , just focus on the correct positioning of the components. Have the circuit diagram for help.

 

[Wordsushi]

This is the only pic I have of a populated Homero V1.0 board. Hope this helps.

Also, just in case you need it, the tranformer pads connect like this.
P- = tx2
P+. = tx1
S- = tx4
S+. =tx3

 

[Wordsushi]

Thank you! Taking it out of an 87 style body and putting it into a round headbasket body made a huge difference. I'm very pleased with this one. I'm going to have to make some plans to use it. Maybe I'll have to do some of that stupid ASMR stuff with it.

The Nano however is dead. I had tried a different 103 style body shell and had the same issue.

Arienne gave me some pointers after identifying the noise as 2.4ghz wifi, which makes sense because my booth is not far from the router (which can't be moved).
I had XLR 1 connected to the ground plane on the board instead of just to the body, which she said was causing a loop. So, I altered the PCB and rewired it and I must have borked it somewhere because now I have no signal and 48v reading everywhere. I'm at a loss as to why this one and not the other one or the larger body ORS87s I've built, so I'm just going to chalk this one up as a loss. I've started stripping the board for the parts to rebuild another one the way I did the first one again. Live and learn. At least I know now I like this combination of Bai Fei Li k87 capsule and Ali T-13 transformer on this one.

Yes, the Bai Fei Li capsule with the black ring is available on Aliexpress for about $38.

 

[micolas]

Yes, the Bai Fei Li capsule with the black ring is available on Aliexpress for about $38.

I guessed, they looked identical.
Thank you very much!

https://a.aliexpress.com/_Euumbh9

 

[micolas]

Found another one build by @Wordsushi

 

[untamedfrontier]

While I'm still waiting for my boards to arrive; I've also ordered the baifeili 87 capsule, HL-95 body, and a shockmount from aliexpress, but I assume the HL-95 body is not going to arrive with any sort of XLR connector.

I'm assuming this one will be the best XLR connector for our purposes: Amphenol Audio AC4-MIC

Any other suggestions or recommendations? I saw a switchcraft QG5M as a similar option but $15 for an XLR connector seems silly

EDIT: strikethrough of shared part as it's a 4 pin XLR and not the right choice for a standard build. AC3-MIC is the 3 pin XLR connector in the same series

 

[micolas]

Built by @Highlander