Is the K47 capsule too dark?

[kingkorg]

Hello
I am following this thread about K47 capsules and I ask myself, are all AliExpress K47 capsules the same?
There is a lot of different prices and it will be a couple of different manufacturers, so, it makes sense to compare it with original ones?
I think there is a lot of different sounds, different manufacturers, different qualities in AliExpress. Maybe the same seller could sell capsules made in different manufacturers. So, I think that is really difficult to discover which is the sound or quality of "AliExpress capsules".

You are right. But there seems to be at least two distinct sounding k47 from Neumann as well. I tend to prefer flatest sounding ones, as the goal with m7 and k47 was to make it as linear as possible. At least according to the documents. Thiersch tunes them this way too. However k47 from k47 FET is anything but linear. It's cardioid only, no center termination and no gold.

 

[Khron]

At least the legend was that capsules where the two sides weren't closely enough matched went into the FET, but... Perhaps that applied only to the first "batches"?

 

[RuudNL]

Yes, as far as I know it wasn't recommended to use the rear diaphragm, because the capsules were 'rejects' and only the 'good' side was used in a U47 FET.

 

[Khron]

I like their attention on packaging. Frequency response for this would be flat dead ...

I also bought some k47 style capsules from 77jc, and the plastic housing was also a bit broken. But atkeast the capsule wasn’t damaged.

I've actually got a few 77jc capsules on the way myself - fingers crossed.....

Well, finally picked mine up from the post today. Most of the casings were not intact, but no sliced diaphragms or anything. QC on the other hand could use some improvement too...

One of the K47's has quite the noticeable "ripple" near the center termination, and two others have some backplate burrs poking out. Two of the "CK12's" have one little burr each as well, visible with the naked eye, but couldn't capture it in a photo.

How concerned should i be about those burrs, if at all? Sure, it points to lackluster QC, but would they affect the sound / signal in any (meaningful) way?

Although now i'm starting to wonder whether the creased one migh thus have more "vintage mojo"... [End of sarcasm - really sorry, couldn't help myself, making the best of a less-than-ideal situation]

 

[shabtek]

you might be able to get the wrinkle out by adjusting the screw --might not notice a sound difference with it.
I have a k47 in a tlm that has a little wrinkle like that. fwiw it must have passed tlm49 q.c.
put on some gloves

 

[Khron]

you might be able to get the wrinkle out by adjusting the screw --might not notice a sound difference with it.
I have a k47 in a tlm that has a little wrinkle like that. fwiw it must have passed tlm49 q.c.
put on some gloves

Thanks for the tip! I unscrewed that maybe... 1/8th of a turn, if even that? That removed the wrinkle indeed, and i slowly retightened it a bit, without creasing it up again.

 

[soliloqueen]

What's more pressing is those weird lumps under the diaphragm...unbrushed shavings from the backplates?

Oh, you already mentioned that. I saw those and came straight here...that's definitely an issue. How much did you pay?

 

[Khron]

I figured those weren't supposed to be there, i was just wondering how much of an issue i might expect them to be. And these 4+4 cost me 215eu with shipping, plus customs. All in all, not too bad, assuming they all work...

 

[kingkorg]

Well, finally picked mine up from the post today. Most of the casings were not intact, but no sliced diaphragms or anything. QC on the other hand could use some improvement too...

One of the K47's has quite the noticeable "ripple" near the center termination, and two others have some backplate burrs poking out. Two of the "CK12's" have one little burr each as well, visible with the naked eye, but couldn't capture it in a photo.

How concerned should i be about those burrs, if at all? Sure, it points to lackluster QC, but would they affect the sound / signal in any (meaningful) way?

Although now i'm starting to wonder whether the creased one migh thus have more "vintage mojo"... [End of sarcasm - really sorry, couldn't help myself, making the best of a less-than-ideal situation]

Bugger. My k47s from the same supplier arrived today. While they were intact, they don't really sound like k47. They have a bump at wrong spot, and way too large. The sides are exceptionally well matched though. Rear response typical of k47.

For anyone building a u47 with these, you need to get rid of this bump. The capsule is pretty sibilant in worst possible area. I'll probably go with RLC network to fix it.

UPDATE:
Looking at Audio test kitchen graphs, which i confirmed to be quite accurate, Roswell mini k47 has this exact bump at 5K. I suspect this is just cosmetically updated Microphone Parts capsule.

 

[kingkorg]

Just for example here it is against @soliloqueen 's k47 which is just perfect. Soliloqueen's is the blue one. I hope you don't mind me publishing the graph.

 

[kingkorg]

I transfered the Roswell Mini 47 ATK (blue)measurement to REW, and here it is against my capsule. Indeed they seem to be the same thing.

 

[Khron]

I kinda wonder if an RLC notch would be necessary, or if something like a (fixed) big-muff-tone-control-like thing would achieve something similar. Just thinking of resistors and caps being available in private part stocks in a wider range of values than inductors...

 

[Khron]

Just for example here it is against @soliloqueen 's k47 which is just perfect. Soliloqueen's is the blue one. I hope you don't mind me publishing the graph.

Hum-de-hummm... Is it just me, or is the top end of this Neumann (that you posted in another thread) drooping way below the midrange? If that's the case, would some (gentle) low-passing get the response of these 77JC capsules closer to the original, in fact?

 

[kingkorg]

Hum-de-hummm... Is it just me, or is the top end of this Neumann (that you posted in another thread) drooping way below the midrange? If that's the case, would some (gentle) low-passing get the response of these 77JC capsules closer to the original, in fact?

Wrong link?

 

[Khron]

Very wrong indeed, updated now

 

[kingkorg]

That's u87, measured in Neumanns QC(smaller) chamber. And yes it seems wrong even though u87 should have some hf attenuation, but not that much.

That curve will heavily depend on their calibration they use there, and even though it leaked through "How its made", it's not meant for general public. It could be relative, not absolute frequency response.

There might be another thing at play. That would be a typical response for F8. It could be they tested it in F8 mode, to be able to measure both front and back. However we don't know, it isn't obvious in the video.

 

[Khron]

Ooooh, right, ok. Well, it was just a thought. Guess the big-muff-tone is back on the table (?)

 

[kingkorg]

There is this response i posted of Geffel's M7 though.

https://groupdiy.com/attachments/20220120_200603-jpg.88953/

It is M7, so their response is all over the place. In that realm, with such tolerances our capsule would be just fine i guess.

However i'm following Thiersch's school of thought where he tunes M7 to be as flat as possible. This was also Neumann's original idea. Flat mic-true to the source.

There is one more thing bugging me. @tomas.borgstrom posted his files where his Neumann k47 capsule has similar bump in the same area. In case the Alibaba capsule he posted is flat, that would mean our k47 capsule is much closer to his Neumann. However i've never encountered any measurement or capsule from Neumann that has this bump. The only one k47 based with this bump on ATK is Microphone Parts capsule.

 

[soliloqueen]

The Neumann k47 does indeed have a bump at 3 to 5 kilohertz. Mine was designed to split the difference between the k47 and the M7 which judging from the traces of both in this thread I think it does pretty handily

 

[kingkorg]

Well, it seems we might have stumbled upon a capsule that is close to the one Tomas owns. U47 Fet at ATK has a bump there, but a 2.5db one. M149 doesn't have it, even though if has transparent grille. My measurements were taken without grille, so my bump could come down a bit when i install it in traditional body. These things are really all over the place. Even Neumann's seem to be. The 47 different voicings of the k47...