FET847 Microphone Project Circuit By Jonathan Burtner PCB Layout By Poctop

[Khron]

Might you have mixed up which lead needs to go where?

What sort of resistance can you measure between that 5th lead, and each of the other four?

 

[karloff70]

Might you have mixed up which lead needs to go where?

Well, I might. I did measure them before soldering and got one pair with 350 or so ohm and one pair with 50 ohm, and one spare. Let me reinvestigate.

 

[Khron]

"The easiest person to fool is yourself" - i'm quoting AvE, but I've been on the receiving end of that experience more than once myself...

 

[elskardio]

why not invest $39 and be done with it

https://www.ebay.com/itm/1115409026...CpxnatIa8y0ron77YlaWckcA==|tkp:Bk9SR_jUptPDYg

 

[karloff70]

Soooo.....my wiring was correct. But the damn leads from the old Beyer are so frail, one broke at the very edge of the yellow heatshrink coming out of it and I didn't see. Repaired and mic sounds loud, silent and at first glance, pretty great. Tonight I shall tweak the fet screw by ear and see where it lands. Happy days.

 

[Khron]

Still don't quite see the point of those humongous and "fancy" 100nF caps that only filter the capsule bias voltage, and the twisted-wire mounting might have not-100000%-certain reliability, but that's just me, and i'm weird

 

[karloff70]

Still don't quite see the point of those humongous and "fancy" 100nF caps that only filter the capsule bias voltage, and the twisted-wire mounting might have not-100000%-certain reliability, but that's just me, and i'm weird

Fair. As you can tell I'm weird too, or they wouldn't be there lol. Either way, for now the only other thing that interests me is that fet tweaking screw. Once I have that where I like it best foe my oersonal vocal use and do some test recordings I might get inspired to get weirder from there and swap some stuff, endangering the board some more. Or not.

For now I feel massive relief. And I also have another board, capsule and transformer that only need a body and parts for the board, so then I could try some others, like your very well priced list from earlier, and see whether a) I hear a difference and b) if I prefer the cheaper parts haha

But I have music to get recorded and one of these is enough for my needs right now so likely it's now time to focus on using these tools for a while before more builds. There are a pair of Soundskulptor mu524s ready built on their way to me, and this mic, going into an Olympic mic/eq65 and into the mu should make a pretty inspired vocal chain. Excited!

 

[karloff70]

Keep us posted about the outcome with these Beyer transformer, please. I am very interested because I have some of them laying around here.

So, I'd say totally do it. The little Beyer makes it sound like a classy vintage mic, exactly as I had hoped. Awesome. And the Ari Flat k47 capsule is banging. The Trans67 is alive and kicking, and it does exactly what I had hoped, especially with a little eq from the Olympic amps on the way in, pushing a little baxandall 250 and a tiny bit of 4.3 to portion in the k47 edge the Flat doesn't have, and boom. Time to make some records.

 

[karloff70]

So my mic is sounding rather nice. Now has Samar capsule inside it plus still the 5:1 old beyer transformer. I can't help thinking whilst the tone is great, the size of sound could be bigger and now eyeing the beyer foe replacement.

I see the microphoneparts T84 kit, which soybded great to me off files eith the Arienne Flat k47 in it, has ehst looks like a kind of U47 type 6.5:1 in it? Anyone built this kit with such a transformer? Could just spend and get a Mony BV107 I suppose but the size is interesting, so a big but cheaper UTM could be interesting if a 6.5:1 meant for U47s would work?

Any thoughts from a higher plane of knowledge than mine about swapping the beyer for something that sounds bigger round the bottom appreciated.

 

[mrgrooves666]

How are you finding the Samar capsule. One thing worth mentioned, I've read references, due to its multiple chamber design, that this capsule has a very controlled and natural proximity effect, could this be what you're hearing?

 

[karloff70]

It sounds awesome and yeah, I am hearing that. I am also hearing it sound VERY smooth off axis in a spooky way for a cardioid. Sweet. But no, the want for more size below is not that and I can tell those things apart.

I had an Arienne Flat k47 in there first which has a big bottom and it was the same so I am thinking it is the beyer. This is why I put the Samar in there, to see if the bottom would change. Didn't. The Ari kind of sounds a bit cooler but the Samar more real.

Will try a bigger transformer with both, see where it lands.

 

[JW]

Is a 6:1 transformer okay?

Here are two Xformers,(the first is 6:1, the second 6.9:1) from UTM that should work. Is one better than the other? Any thoughts? The first is cheaper, and should theoretically provide slightly more gain.

https://utmindustry.com/utm0547/https://utmindustry.com/utm0567/

 

[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.

I finally reopened my pair of FET847 yesterday to install new capsules (Arienne's Flat 47).

I took the opportunity to replace R2 with a 30M resistor and this brought down the warm-up time to 5 seconds

 

[Khron]

I took the opportunity to replace R2 with a 30M resistor and this brought down the warm-up time to 5 seconds

Safe to assume there was zero noticeable noise difference..?

 

[elskardio]

Safe to assume there was zero noticeable noise difference..?

None that I could ear.

 

[doqmemory]

None that I could ear.

I see what you did there.