Keyboard Shortcuts
Likes
- MicBuilders
- Messages
Search
|
Re: Dismantling LDC to use capsules as ORTF in a blimp
On Sat, Mar 1, 2025 at 09:50 AM, Heinz wrote:
?
I forgot to mention that if you scroll through the photos of the album and click once on the little "i" (information) circle in the top right corner of the screen, you will get useful descriptions for some of Magnús Bergsson's photos.
|
|
Re: Dismantling LDC to use capsules as ORTF in a blimp
Hi Damian
Magnus Bergsson shared a photo album about his NT1a approach.
You'll find it here:
Heinz
?
?
On Fri, Feb 28, 2025 at 03:09 AM, <damiandrohanphoto@...> wrote:
I spotted an old youtube video recently, where the guy dismantles a pair of Rode NT1a to capsule and pcb, and fits them in a blimp, and I'd like to do something similar. I have a pair of LDC I bought recently, heavily discounted, that I can use. |
|
Re: Dismantling LDC to use capsules as ORTF in a blimp
On Thu, Feb 27, 2025 at 04:09 PM, <damiandrohanphoto@...> wrote:
I occasionally record in places with people around and like to try to keep my setup fairly discreetWith mic capsules that size... for wind protection? you're going to end up housing them in a standard zeppelin, sideways. That's hardly discreet ;-) ?
Anyway, I don't think there's much "off-the-shelf" stuff you can find for mounting the capsules and electronics. Perhaps some Rycote lyres can be modified to be shock-absorbing mounts for the capsules. You could buy some inexpensive shockmounts with elastics for sdc mics, and cut those down and modify. Or bits of rubber hose. Etc. It'll be a fun challenge.
?
? |
|
Re: Dismantling LDC to use capsules as ORTF in a blimp
@Cram, thanks for the links. The rig you're making looks cool. I hadn't thought about being limited with the capsules in a blimp, I guess I just assumed I could manage an ORTF arrangement. The mics were so heavily discounted that I figure I have nothing to lose. They're not actually NT1as, they're "Neat King Bee II" which are even bigger and heavier. I'll throw a link below.?
?
I think I'll just have to get my hands dirty with some DIY efforts, just have so little experience of it. I admire people like Dr Bad Phil- who you linked to, who can just turn out designs.
?
Here's the mic link: .?
It's so big and unwieldy that it's hard to see how it could be used any other way in the field, than dismantling it.
?
I did buy a pair of the baby brother to that mic (worker Bee II), which are signficantly smaller (but noisier- 11db versus 6.5db) They might be more amenable to using as-is in the field. |
|
Re: Dismantling LDC to use capsules as ORTF in a blimp
开云体育I hear you. I’ve got a few omnis (em272 and aom5024) in various configurations, but I’ve been wanting to play with some cardioids also for ambience and nature sounds etc. The self noise specs of the nt1a were hard to pass up, and the price is nice too. ? I’ll definitely concede they’re large mics (180mm long, 50mm dia.) and I can’t see myself hiking with my setup. That link you shared has also been one of my inspirations. For reference,
this is the sort of thing I’m building: ? From: [email protected] <[email protected]>
On Behalf Of damiandrohanphoto via groups.io
Sent: Friday, 28 February 2025 8:10 AM To: [email protected] Subject: Re: [MicBuilders] Dismantling LDC to use capsules as ORTF in a blimp ? @Cram, I'm dismantling them to make the whole thing a bit more portable. I like the idea of something I can set up fairly quickly- then it will get used and my laziness or procrastination won't put a halt to it. Plus I occasionally record in places with people around and like to try to keep my setup fairly discreet. ? Magnús Bergsson has made some really nice recordings using dismantled NT1As and Lewitt 540S - ? I guess if I had the budget I'd probably get a pair of Sennheiser or DPA sdc for the smaller form factor. ? Really I'm just trying to get more detailed/low noise recordings in a fairly cost effective way but trying also to keep the footprint fairly small. ? ? ? ? ? ? ? This email has been scanned for spam and viruses by Proofpoint Essentials. Click to report this email as spam. ? |
|
Re: Dismantling LDC to use capsules as ORTF in a blimp
@Cram, I'm dismantling them to make the whole thing a bit more portable. I like the idea of something I can set up fairly quickly- then it will get used and my laziness or procrastination won't put a halt to it. Plus I occasionally record in places with people around and like to try to keep my setup fairly discreet.
?
Magnús Bergsson has made some really nice recordings using dismantled NT1As and Lewitt 540S -
?
I guess if I had the budget I'd probably get a pair of Sennheiser or DPA sdc for the smaller form factor.
?
Really I'm just trying to get more detailed/low noise recordings in a fairly cost effective way but trying also to keep the footprint fairly small.
?
?
?
?
? |
|
Re: Dismantling LDC to use capsules as ORTF in a blimp
开云体育I’ve just sourced a pair of old nt1a’s to run in a stereo field rig also, but I’m making individual blimps for them. ? From: [email protected] <[email protected]>
On Behalf Of damiandrohanphoto via groups.io
Sent: Friday, 28 February 2025 4:02 AM To: [email protected] Subject: [MicBuilders] Dismantling LDC to use capsules as ORTF in a blimp ? Hi all. ? I spotted an old youtube video recently, where the guy dismantles a pair of Rode NT1a to capsule and pcb, and fits them in a blimp, and I'd like to do something similar. I have a pair of LDC I bought recently, heavily discounted, that I can use. The video is here: ? I won't be needing his powering solution, or preamp circuit as I'll just use a Zoom F3 externally to supply a preamp and phantom power. ? I'm curious if anyone has done similar with LDC capsules and experience on protecting and mounting the capsules and circuit boards in a blimp.? ? thanks in advance Damian ? ? This email has been scanned for spam and viruses by Proofpoint Essentials. Click to report this email as spam. ? |
|
Dismantling LDC to use capsules as ORTF in a blimp
Hi all.
?
I spotted an old youtube video recently, where the guy dismantles a pair of Rode NT1a to capsule and pcb, and fits them in a blimp, and I'd like to do something similar. I have a pair of LDC I bought recently, heavily discounted, that I can use.
The video is here:
?
I won't be needing his powering solution, or preamp circuit as I'll just use a Zoom F3 externally to supply a preamp and phantom power.
?
I'm curious if anyone has done similar with LDC capsules and experience on protecting and mounting the capsules and circuit boards in a blimp.?
?
thanks in advance
Damian |
|
Re: PiP capsule hum
开云体育
Le 25/02/2025 à 19:16, Casey via
groups.io a écrit?:
I don't think so. It looks like there's more EMI/RFI near the capsule. Why, IDK. It depends on too many factors. Or perhaps the splice near the capsule is more exposd than the other.
|
|
Re: PiP capsule hum
开云体育
Got it, thanks for the education. There is a splice near the capsule, now shielded, and a splice near the plug which is not shielded. The second splice does not cause hum -- is that because it is further from the capsule? -c |
|
Re: Alctron MA-1 Schematic question
Well, the posted Alctron MA-1 schematic certainly has at least one error! The idents of Q3 and Q4 are reversed.?
As Jerry has surmised, the cascode amplifier inverts the signal.
I can confirm that the signal present at the drain of Q2 is connected to pin 3 on the MA.1 pcb, and in the inverse polarity of the signal present on pin 2 of the input.
So the polarity of the signal is reversed by the device.... which is presuambly why the output connections are reversed? |
|
Re: PiP capsule hum
开云体育
Le 25/02/2025 à 08:16, Casey via
groups.io a écrit?:
Yes indeed.It's a two-wire capsule () -- AFAIK the ground terminal is connected to the capsule body in that capsule. I have continuity between capsule body and plug sleeve. It just seems like the connection between the cable and the capsule (maybe 5 or 6mm) where the wires are exposed is enough to admit hum?Not in normal circumstances. Are you sure that the body in which you put the capsule is properly grounded?
|
|
Re: PiP capsule hum
开云体育It's a two-wire capsule () -- AFAIK the ground terminal is connected to the capsule body in that capsule. I have continuity between capsule body and plug sleeve. It just seems like the connection between the cable and the capsule (maybe 5 or 6mm) where the wires are exposed is enough to admit hum?Not in normal circumstances. Are you sure that the body in which you put the capsule is properly grounded? No: there is no body -- well, no metal body; it's inside a bakelite antique wall-mounted telephone mouthpiece. I was under the impression that a 2-wire PiP capsule acts as its own shield so I didn't need shielding, but apparently I'm wrong and the join from cable to capsule does need to be shielded? -c
|
|
Re: PiP capsule hum
开云体育
Le 24/02/2025 à 23:09, Casey via
groups.io a écrit?:
Not in normal circumstances. Are you sure that the body in which you put the capsule is properly grounded?
|
|
Re: PiP capsule hum
开云体育Thanks Chris and Jerry: Jerry wrote:
It seems to indicate that the capsule body is not properly grounded.It's a two-wire capsule () -- AFAIK the ground terminal is connected to the capsule body in that capsule. I have continuity between capsule body and plug sleeve. It just seems like the connection between the cable and the capsule (maybe 5 or 6mm) where the wires are exposed is enough to admit hum? Chris wrote:
If I use my separate stereo PiP mic, which is wired one capsule
to tip and one to ring, both mics work in this interface (meaning,
their input shows up in the mono output)... does that contradict
anything that you said above? E.g. it seems that ring isn't just
for power but is actually receiving a separate signal (which is
mixed to mono before going to the computer). Also, currently the mic is just wired signal-to-tip,
shield-to-sleeve, so ring isn't connected to anything, and it
works (with hum), implying that the bias isn't only on ring?
I may have been unclear: connecting tip and ring does work, it
just didn't eliminate any hum so it didn't solve the issue.
I admit being mystified at the myriad ways there seem to be for
1/8" jacks to be wired, so I don't know if it matches or not, but
PiP is just "plug in power" referring to lower voltage supplies on
(usually 1/8") mic inputs.
Yeah that seems to solve it completely. -c
|
|
Re: PiP capsule hum
It seems to indicate that the capsule body is not properly grounded.
toggle quoted message
Show quoted text
In 3-wire connection, there is no need to shield teh capsule, as long as the body is connected to teh shield. Check your connections. Le 24/02/2025 à 21:59, Casey via groups.io a écrit?:
Progress! Aluminum foil wrapped around the capsule body (but not covering the face of it), which covers the wire connections to the capsule from the wire, makes the hum disappear. I'll solder in some copper foil to the situation. |
|
Re: PiP capsule hum
On Sun, Feb 23, 2025 at 06:01 PM, Casey wrote:
I believe the the audio interface is providing a stereo 1/8" jack, but it mixes to mono internally It is not stereo, it is standard PC microphone wiring of a TRS jack, sleeve is shield + signal and power return, tip is signal, and ring provided power for a capsule with built-in FET.
The Amazon page you linked shows pretty clearly that a TS jack is not supported, so I would think that a TRS jack with both wires connected together at either end would be electrically equivalent, and would also not work.
However, most of the information I could find about PC standard microphone connections indicated that both the resistor and the DC-blocking capacitor are typically in the audio interface, in which case I don't see why connecting tip and ring together at any point would not work.
?
The microphone input likely meets the old PC2001 connector requirements:
If the PC has an analog microphone input, it must meet the following
specifications: ? Three-conductor 1/8-inch (3.5 millimeters) tip/ring/sleeve microphone jack where the microphone signal is on the tip, bias is on the ring, and the sleeve is grounded. This design is optimized for electret microphones with three-conductor plugs, but will also support dynamic microphones with two-conductor plugs, where the ring and sleeve are shorted together. ? Minimum AC input impedance between tip and ground: minimum, 4 kilohms. ? Input voltages of 10–100 millivolts (mV) must deliver full-scale digital input, using software-programmable gain. ? Maximum 5.5 V with no load, minimum 2.0 V with 0.8 milliampere (mA) load, direct current bias for electret microphones. ? Minimum bias impedance between bias voltage source and ring: 2 kilohms. ? AC coupled tip. ?
If that is the case then indeed you should be able to connect tip and ring together, which wires to the drain terminal of the on-capsule JFET (term 1), and the sleeve connection to the term 2 ground connection of the capsule.
?
?
I am not familiar with"PiP," does it match that connection described above?
Do you also have an electrostatic screen of some kind which surrounds the capsule?
?
I see that there is another response which came in while I was typing which indicates that you did add better shielding using conductive tape.
?
Correct, you cannot use a TS plug, because that will short the bias power to ground, meaning no power to the electret capsule JFET.
You can use a TRS plug and short T and R together, but you cannot short T and S together.
?
-- Chris Caudle |
|
Re: PiP capsule hum
Progress! Aluminum foil wrapped around the capsule body (but not covering the face of it), which covers the wire connections to the capsule from the wire, makes the hum disappear. I'll solder in some copper foil to the situation.
Is this standard best practice for PiP mics that I should have known about? Get a mono plug. It'safer.I think we've shown that it makes the mic go dead, though? When I connect ring to ground (which I think is what a mono plug will do, right?) the mic goes totally dead. How is the capsule shielded? Cover the capsule with an empty can. If the hum is gone - you have improperly or insufficiently shielded capsule.Per above, this indeed seems to be the issue! -c |