MXL 603 -> KM84 Replacement PCB

[JerryPbury]

Response of these capsules will heavily depend on what's behind them, how large the chamber is, if it's vented or not. Km84 has shallower chamber and no additional vents that MXL bodies have.

You’ll have twice as many vents with the 3U capsule.

 

[kingkorg]

You’ll have twice as many vents with the 3U capsule.

That is true, but not necessarily better. The dome which difuses the sound will be placed considerably lower in the tube of the MXL compared to km84. Once again, these things are way more important and will introduce more audible deviation from the original than any change in the circuit of this particular mic. Even if you compare mxl stock circuit versus the km84.

Slot size on km84 capsule is carefuly tuned and is the part of the delay network. Using more slots is in a way the same as widening the holes on the rear backplate of the capsule.

As far as i can see, this capsule is more of a km184 based. It has tighter slots, so potentially even more important.

I suggest using some foam to make the chamber behind shallower, and listen. Record white noise with and without the foam at same exact position and look at spectrum analyzer for differences. 90°, 180° as well. Big part of km84 is off axis sound.

 

[kingkorg]

I managed to dig these two up. This "clone" resembles MXL/3U combo. Easy to se how large the deviation is.

 

[Ricardus]

If I needed to I could use Bondo to close up the vents on the MXL body, just like I am using it to fill in their embossed logo.

Easy peazy,

But for now I can try to put some foam in there and try it like that. I can cut it so it fills the inside diameter nicely.

 

[kingkorg]

Irregularities coming from back of the capsule result, in my experience, 99% of the time in a sharp notch dip somewhere in hi mids/highs. So look for those.

 

[LevinGuitar]

Response of these capsules will heavily depend on what's behind them, how large the chamber is, if it's vented or not. Km84 has shallower chamber and no additional vents that MXL bodies have.

This makes me think why Neumann changed the vents in the KM184, since the KM84 is supposed to have exactly same capsule, right? Does smaller vents compensate somehow the change to a transformerless circuit?

 

[kingkorg]

This makes me think why Neumann changed the vents in the KM184, since the KM84 is supposed to have exactly same capsule, right? Does smaller vents compensate somehow the change to a transformerless circuit?

Well it is not the same, pretty much everyone agrees on that they don't sound the same. Nope, vents affect frequency response and pattern response.

The difference between the km84, km184, mxl circuits would be mostly in how they saturate, how much spl they can take, noise....

 

[Ricardus]

Should be getting my transformers for these today. Should have some working mics by weekend.

 

[Digitalunderdog]

Hi folks, Merry Christmas, all. I hope everything's treating you well in your parts of the world!

Nice to see people are interested in getting a few boards, I haven't had any made for a bit as it'd all quietened down for a bit, but I'll be doing a run in the New Year so there's some stock for those who're keen.

Please send me a private message if you're interested and haven't already and that way I'll be able to keep track of things.

Have an awesome holiday season everyone, stay safe and well, and enjoy your time with loved ones!

I can't seem to message you, but I would like one PCB please

 

[Ricardus]

OK, finished up #1, except for the repaint of the MXL body. All biased and ready to go. Super pleased with what I am hearing. Need to use these in battle as soon as possible.

 

[EarthTone]

How would these be different from this build? SDC-84 Microphone Kit - Neumann KM84 Style

I did a pair of these mic parts km-84 style sdc’s and also did a pair of mxl-603s-schoeps style circuit conversions and used their capsules for all of them. I think these are the same parts as what’s listed here. Anyway, they all worked and sounded decently good, I used them a lottttt especially for live recordings at venues where I didn’t want to risk taking out my more expensive gear. I think they sound good but when I got a pair of real Schoeps CMC6-MK4 I realized why people pay much more for them. The level of detail is not even a close comparison. That being said, I do like the punch of the tx in the 84 clones. If your circuits do that thing then I would imagine they would be a really fun build and rewarding result for the people who build them. I do personally prefer my similar km84 clones to the schoeps style circuit with the same capsules. More fun and more flavor. Does your tx rattle loosely in your mic body though? The mic parts build does not include any instructions or parts for securing the tx in place, so it can move freely inside. If you shockmount it it’s not a big deal but this unfortunately has prevented me from clamp-mounting it onto an instrument such as the acoustic bass for fear of recording a rattle. Need to go back and figure out a way to secure that tx inside.

 

[Ricardus]

There is a thread on their mics that I started some months ago when I was first interested in adding some SDCs to my mic locker.

https://groupdiy.com/threads/mic-parts-dot-com-small-diaphragm-condensers.81499/

 

[Tubetec]

Some interesting stuff there Ric thanks ,
then it all ends up a in a mess ,

 

[Ricardus]

Some interesting stuff there Ric thanks ,
then it all ends up a in a mess ,

The thread? I was just looking for SDC advice. I got what I needed. In spite of not wanting to build a set, I built a set anyway, and ordered some Oktavas as well since they are pretty universally liked.

 

[Ricardus]

And then there were two:

 

[GraemeWoller]

How would these be different from this build? SDC-84 Microphone Kit - Neumann KM84 Style

I did a pair of these mic parts km-84 style sdc’s and also did a pair of mxl-603s-schoeps style circuit conversions and used their capsules for all of them. I think these are the same parts as what’s listed here. Anyway, they all worked and sounded decently good, I used them a lottttt especially for live recordings at venues where I didn’t want to risk taking out my more expensive gear. I think they sound good but when I got a pair of real Schoeps CMC6-MK4 I realized why people pay much more for them. The level of detail is not even a close comparison. That being said, I do like the punch of the tx in the 84 clones. If your circuits do that thing then I would imagine they would be a really fun build and rewarding result for the people who build them. I do personally prefer my similar km84 clones to the schoeps style circuit with the same capsules. More fun and more flavor. Does your tx rattle loosely in your mic body though? The mic parts build does not include any instructions or parts for securing the tx in place, so it can move freely inside. If you shockmount it it’s not a big deal but this unfortunately has prevented me from clamp-mounting it onto an instrument such as the acoustic bass for fear of recording a rattle. Need to go back and figure out a way to secure that tx inside.

Yeah, they're pretty much the same by the looks of things. Even down to the insulated turrets at the top of the board. But I guess there's not many ways to skin this particular cat.

I certainly prefer the tx flavour, for sure, and I've sized the slot for a reasonably tight fit to avoid the rattles. I've had no issues there and they've done duty on a wide variety of stuff with no problems.

 

[GraemeWoller]

Happy New Years everyone. I hope your holiday period went swimmingly wherever you happen to be.

I'm about to put an order in for a new run of PCBs for this project so if you're keen, and haven't already sent me a message about it, please drop me a line so I can get a good idea of the numbers I'm looking at.

Rock On!

 

[Digitalunderdog]

Looking forward to building these, I have a question about donor bodies. Is it just the MXL603 that will work? I also see someone used an Apex 180, would the MXL 991 work as well?

 

[fsalter]

I have the same question. Will a Nady CM90 work as a donor body with 3u capsule?

 

[klem]

i'm guessing everyone has been using tantalums but i'd love to hear if anyone has found some electrolytics that fit. e.g., for 4.7uF panasonic fc series is 11mm high, and even bending the leads to place the cap at an overall lower height and (less secure) angle, it's just not fitting.
any suggestions?