FET847 Microphone Project Circuit By Jonathan Burtner PCB Layout By Poctop

[lightningbefore]

What did y'all substitute for the obsolete and back ordered parts in the Mouser BOM?

 

[Rybow]

What did y'all substitute for the obsolete and back ordered parts in the Mouser BOM?

There’s a few 1uF 35V 10% options. Any of those would be fine.

For the inductors I used the 1025R-60K without issue.

Hard to beat those little 1/4 watt axial 1G resistors. Digikey has good stock of them
https://www.digikey.ca/en/products/detail/te-connectivity-passive-product/RGP0207CHK1G0/2389890

 

[Ricardus]

FET847 build #1 completed and it sounds pretty damn amazing.

 

[Ricardus]

If anyone wants a quick audio sample from that mic that I made just DM me and I'll send you a link. I'd post it publicly but I'm afraid bots would hit it and just waste my Dropbox bandwidth.

 

[rock soderstrom]

FET847 build #1 completed and it sounds pretty damn amazing.

What capsule do you use?

 

[Ricardus]

What capsule do you use?

I used a Peluso PK47 for this one.

 

[Ricardus]

What capsule do you use?

I will be using soliloqueen's capsules from now on.

 

[Rybow]

I’d be interested to hear some audio samples. I can put a few up as well.

I’m wondering what you gentlemen are using this mic for? I recall reading several posts about expecting a room or overhead mic, and being pleasantly surprised.

I just cut a track using this mic for all my vocals. Really liking it. I also use it for my paid gig on one particular narrator. He’s got that classic deep radio voice, which suits this mic perfectly. On female narrators it’s all kinds of wrong.

 

[Ricardus]

I’d be interested to hear some audio samples. I can put a few up as well.

I’m wondering what you gentlemen are using this mic for? I recall reading several posts about expecting a room or overhead mic, and being pleasantly surprised.

I just cut a track using this mic for all my vocals. Really liking it. I also use it for my paid gig on one particular narrator. He’s got that classic deep radio voice, which suits this mic perfectly. On female narrators it’s all kinds of wrong.

It's like a mini U87i. You can use it for anything.

 

[Ricardus]

Here's a nude I took of the one I finished last week.

 

[Ricardus]

I'm looking for some clever ways to mount the transformer in this housing. Nothing seems obvious to me. What have others come up with?

 

[elskardio]

I'm looking for some clever ways to mount the transformer in this housing. Nothing seems obvious to me. What have others come up with?

Zip ties?

 

[Ricardus]

Zip ties?

I tried a couple different ways and nothing really worked.

 

[JW]

Is it possible to fit the Cinemag 2461 transformer in a bm700/800 body? This is a 6.5:1 u47ish transformer.

 

[Ricardus]

Is it possible to fit the Cinemag 2461 transformer in a bm700/800 body? This is a 6.5:1 u47ish transformer.

I don't think so, but I haven't had one of those transformers in my hands so I don't really know for sure.

 

[elskardio]

With 3x 10M and 3x 100nF filtering for the capsule bias voltage, it should reach its maximum in around "only" 45sec or so

Curious if anyone has tested these values to lower the warming-up time of the microphone?

 

[Ricardus]

Curious if anyone has tested these values to lower the warming-up time of the microphone?

I noticed my KM84 clones take a while to activate also. I'm not too worried about it.

 

[elskardio]

I built my pair 5 years ago and never reopened them... There's nothing to be worried here
But the slow warming-up time is less than ideal. Especially if the circuit can be modified to avoid it.

 

[Khron]

That's what happens when people slap together circuits (more or less) "blindly" or "just because", not always understanding all the how's and why's.

 

[klem]

Sheesh. I for one am appreciative of Jonathan for seeing this project realized in full as a PCB. It may not be as fun to verify what mic bodies, e.g., work with a prototyped PCB than to slag off the design with half-realized improvements, but Jonathan successfully brought a fully supported and documented PCB to the community. You, on the other hand, have focused your energies on demonstrating how much better insight you have to the circuit. But when members ask if they could realize your circuit as a finished PCB, you wouldn't even provide the full set of files to them, much less put in the 'grunt' work in the first post that makes a circuit / project all the more of a valuable contribution to the community. Khron, you make some great points and contributions, you've directly helped me in posts as I learn more EE, and I am grateful for that. I also recognize the significant effort it takes to fully create a project for everyone's benefit,. Criticism has a place, but when a member focuses more energy on tearing down vs. building, I think it says more about the person than the topic.