Tim Campbell
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Early M7's had a hole drilled from the edge to one of the blind holes as a vent
Soliloqueen's k87(k67) and k47 capsules
- Thread starter kingkorg
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Now that's interesting! I've seen some relatively early m7s but not the pre u47 ones. I can see why they stopped. Seems like it would need to be thin.
Someone I know has a really really early M7. Serial number is early double digits. 14? 16? It sounds horrible. The holes are noticeably too shallow IIRC. The M7 is one of those capsules where the early serial number preference common among collectors definitely doesn't pan out. Early M7s are awful, reskinned or not. It's like playing the lottery.
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My M7 i have from Dale (or cathedral pipes, not sure) has this type of hole.
GeorgeToledo
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The earliest Neumann capsules were also designed around collodian as the diaphragm material, not pvc. I think this was true with the earliest M7 as well but maybe it was just the stuff prior.
They charged nitrocellulose film with 60 or 100 volts of static electricity? Good Lord.
GeorgeToledo
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Early Neumann capsules had enough failures that in that era NWDR had approved Hiller, Joachim Wetzel, and maybe others, for refurbishing capsules with new diaphragms.
Things are a bit of a frenzy right now. I'm reorganizing our entire manufacturing chain. Just finished the die for these, so I actually have something to offer in the meantime for anyone who needs them, since they are rare:
spacers for capacitance, plate distance etc, in 30mm screw ring diameter with neumann-style holes. They are precision die cut, not laser or water or micro CNC or anything that would cause the edges to curl or melt. They are completely uniform in thickness. This one is 50um, but I could probably customize thickness now that the dies are done. The hole cutout is 1.6mm, so keep in mind compatibility with your design. The visible marks are fog from the humidity of my hand.
spacers for capacitance, plate distance etc, in 30mm screw ring diameter with neumann-style holes. They are precision die cut, not laser or water or micro CNC or anything that would cause the edges to curl or melt. They are completely uniform in thickness. This one is 50um, but I could probably customize thickness now that the dies are done. The hole cutout is 1.6mm, so keep in mind compatibility with your design. The visible marks are fog from the humidity of my hand.
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oscarhuang
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This spacer is very important and really hard to find, thanks Arienne.
Thanks! I made sure that it was correctly-dimensioned for most backplate variants out there and wouldn't overhang. The die and press are both pretty high-precision, so none of them clip the holes to the inner diameter so far. The film, too, was selected pretty carefully. My Mitutoyo cannot discern any variation from 50um over the full surface or spot-checking any of the portions with constant force. I don't have the equipment to actually examine the surface at my office, but my best guess is that the final spacers post-cut are consistent in thickness to about 2 HLB. Possibly overkill, but I wanted to make sure the screws w insulation could clear without getting caught on rough edges and the thickness consistency was a nice boon.
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McIrish
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Does it make any sense to put a hole in the Flat 47 back diaphagm? I'm in no hurry to damage it. I'm just kind of curious about this.
I'm really looking forward to when Ari releases the accurate K47 capsule. That would be an instant buy.
You can use a very small (and very sharp) needle to put a hole on the back diaphragm outside the gold to solve this problem, yes. I will replace it if you break it. Tighten the ring screws before you do it to make sure they can withstand the force without pulling downwards.
In high school I always burned my worn out guitar picks, being the little pyro that I was back then.
Quickie Sidebar -- This brief, yet interesting exchange between Mr. @kingkorg and Mr. @Whoops concerning shielding during testing reminds me of the highly professional, super scientific temporary EMI/RFI shield, mini Faraday cage I made with a familiar household product whilst testing those low cost Chinese condenser circuit boards. (see photo) Don't laugh - it worked well and was a super down and dirty on-off-on again bit of test gear! One does what one can with what one has, although I am confident it may have worked better had it not been removed from my last pan of lasagna . . .
Happy trails, y'all. Now, back to the regular program. James
As a part of "r&d" Ari asked me to make a hole and see if it makes any difference in sound. I did so, and that is the capsule i kept and use as my favorite k47 to this date. However it did not make any change in the sound, not sure if it makes difference at high spl.
I wouldn't personally do it again as it makes the capsule vulnerable when it comes to humidity and dirt.
If it works who cares how fancy it looksQuickie Sidebar -- This brief, yet interesting exchange between Mr. @kingkorg and Mr. @Whoops concerning shielding during testing reminds me of the highly professional, super scientific temporary EMI/RFI shield, mini Faraday cage I made with a familiar household product whilst testing those low cost Chinese condenser circuit boards. (see photo) Don't laugh - it worked well and was a super down and dirty on-off-on again bit of test gear! One does what one can with what one has, although I am confident it may have worked better had it not been removed from my last pan of lasagna . . .
Happy trails, y'all. Now, back to the regular program. James
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I tension diaphragms by stretching mylar using regular tape onto a 150gr gym weight. I don't skin diaphragms often, so no point to invest in "prettier" solution.
I also did this once, and it worked like a charm
https://groupdiy.com/threads/m7-diy-reskin.67303/
It definitely does, and it makes the capsule way harder to clean and restore decades down the line, but not moreso than any vintage neumann with the same issue. It's up to you.
Ari, tell me, do you already have a brighter flat 47 version ready to test? Above 10Khz with a nice clear increase, but less annoying parts in the upper middle range from 2.5kHz onwards than almost all common K47s on the market out there have, and borderline ingeniously linear down to the tenth of a second wavelength range, like your Flat47. I'd buy a pair right away, .... I'll call them "Half Flat 47"
You want a little bit more air at 10k? I might be able to do that. Let me check to see how the k47 reacts to me messing around with the plate
Your Flat 47 is a excellent capsule for taming the "brighter"47 Fet circuitry. Just awesome imo in this circuit.
I've just finished a couple of Poctops Dual D-47 Tube Mics and playing around with your 47 Flat and Dachmans 47 capsule in theses mics (Dachman 47 capsule by the way sounds great, has very nice highs, sounds very valuable, has a nice lowend, but is unfortunately at the 3- 7kHzmore emphasized). The Flat 47 in the 47 tube sounds really great in my opinion. But a nice air boost over 10kHz and above would be "subjective estimated" the overkill in the 47 tube mic design. Thank you....
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