Oh yes!! If you start making C12 capsules someday you will become my sole source for LDC capsules.
Soliloqueen's k87(k67) and k47 capsules
- Thread starter kingkorg
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check this out. Here are a few flat k47s with the new metal, relative to the target, and for fun, a somewhat dark k47v relative to the same target at 1/48 smoothing:
We've reached best in class performance here. The differences in sensitivity are exclusively due to the plastic spacers being too squishy. We've reached zero metal influence and near-zero diaphragm tension influence on the capsule response.
Matched at 0dB:
Let's zoom way the hell in:
These remaining differences are broadly due to minor positioning differences in the test microphone due to our rig being kind of jank and having the test speaker way too close to get over the noise. We've reached the limit of shop floor testing.
We've reached best in class performance here. The differences in sensitivity are exclusively due to the plastic spacers being too squishy. We've reached zero metal influence and near-zero diaphragm tension influence on the capsule response.
Matched at 0dB:
Let's zoom way the hell in:
These remaining differences are broadly due to minor positioning differences in the test microphone due to our rig being kind of jank and having the test speaker way too close to get over the noise. We've reached the limit of shop floor testing.
That‘s pretty impressive!
The U67 gets feedback from a winding in the transformer, as opposed to 'local' feedback, so yes, I think that there would be phase issues, that would soften the sound on the treble.
Not sure if this was intentional or not. Usually, when a load-dependent winding is used in feedback, the design aims to minimize problems due to load mismatch.
I should really do this but I've been too busy on the business side of things to get much studio time in. Any volunteers? @tomas.borgstrom maybe?
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I can record some acoustic guitar with an identical setup this week.
Sorry for drafting you. Only if it's convenient, thank you very much.
I think for funsies I'm going to offer linen phenolic rings as an option. This won't affect the sound or the reliability, it's just because I think vintage capsules made with linen phenolic look cool
I made capsules with phenolic paper:
(Don't worry we've already replaced and pickled these screws) which looked almost the same but the weave was too small:
Which suggests that the vintage rings are the same material but with linen rather than paper. So now I'm tracking down some phenolic linen instead
I made capsules with phenolic paper:
(Don't worry we've already replaced and pickled these screws) which looked almost the same but the weave was too small:
Which suggests that the vintage rings are the same material but with linen rather than paper. So now I'm tracking down some phenolic linen instead
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soapfoot
Well-known member
You are my kind of insane
Loving this!
Congrats on the in-house metal
Exciting developments!
Loving this!
Congrats on the in-house metal
Exciting developments!
I would appreciate that, thanks from me as well!
Would it be possible to also record male voice? I'd like to hear the response to sibilants as well as the overall vocal timbre.
Actually... I went and looked at the U67 schematic again, and I can't see any LPF, only the rumble filter and HPF....?
In the U77 and U87 there is a LPF incorporated.
Full-band feedback from the winding is there, which is odd for a microphone, and is likely there to reduce transformer distortion. Some transient response artifacts might be a result of that.
This would imply that it is the transformer itself which is rolling off the treble, similar to an SM58 or something.
Wow..
That 'phasey' sound might be because of 'transformer distortion'
I used to own one and thought it was a bit soft.
It became a lot harder sounding, and cleaner, once I replaced the 1 uF electrolytic coupling capacitor with a new one.
60 year old electrolytic caps certainly do have a soft, dark, distorted sound..
Well, that 100-160pF capacitor has a lot to do with that... It's anything BUT conventional.
where do you see that?
EDIT: oh, ok, I had the first version, which didn't have the cap.. now I remember... LOL
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In every OTHER U67 schematic...
https://groupdiy.com/threads/u67-de-emphasis-network.68495/
The one you posted is probably THE first iteration, going by the "U67-00-00-00S" designation. The one i linked is "-03S", so likely a tad newer.
Bringing the discussion back to capsules, this is the capsule which I took off an early 60's Neumann... I think it was 60 ish anyhow..
The rings are in brass.
Because of the significant damage due to radio use, on the front side, I then substituted the capsule with a new Neumann K67 (15 years ago), and thought the sound was inferior, so I went and sourced an original 1969 ish headbasket and used that capsule instead.. much better IMO..
The rings are in brass.
Because of the significant damage due to radio use, on the front side, I then substituted the capsule with a new Neumann K67 (15 years ago), and thought the sound was inferior, so I went and sourced an original 1969 ish headbasket and used that capsule instead.. much better IMO..
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They were brass for a short period before they were changed out because of the risk of shorting. If the Rings are metal, it becomes easy for salt from spit or weather to create a conductive pathway from the ring, which is grounded to the back plate, to the active diaphragm. It's also for obvious reasons difficult to make a k87 with isolated backplates with metal rings because the metal rings would short the backplates together through the screws. Machining was also quite good during this era before taking a serious nosedive into the 70s and not recovering until the 90s. There are a few anatomic differences that cause differences in sound between the generations of capsule but none of them are easily visible. Sorry for any weirdness I'm using voice to text
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My k87 is based on this exact version with the following limited changes:
All screws changed to m1.4 for ease assembly
Removal of the side grooves for the old style Mount that I don't think was ever used in a mass production Neumann product? But I may be wrong
I also removed the plastic pegs and the implemented a different way of back plate alignment during assembly.
But otherwise, it's identical.
All screws changed to m1.4 for ease assembly
Removal of the side grooves for the old style Mount that I don't think was ever used in a mass production Neumann product? But I may be wrong
I also removed the plastic pegs and the implemented a different way of back plate alignment during assembly.
But otherwise, it's identical.
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Do you mean this? I’ve seen it in one U67. I should have written down the serial number.
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One interesting thing I just saw on my photos, is the presence of what appears to be 8 small beads of something or other arranged symmetrically on the membranes, close to halfway between the rim an center..
Are these the spacers that were mentioned, in order to avoid clinging to the backplate in dry atmosphere?
If they are on the membrane itself, would they not add mass?
Are these the spacers that were mentioned, in order to avoid clinging to the backplate in dry atmosphere?
If they are on the membrane itself, would they not add mass?
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