Re: Alctron MA-1 Schematic question
On Thu, Feb 13, 2025 at 02:37 AM, Goran Finnberg wrote:
Is this really the original schematic or a fake copy.
Unknown. This is one I found from multiple net sources, but the origin was not stated.?
However, the circuit seemed suspicious, which led to my question. The FET info makes better sense now, yet the design purpose is only inferred. I am trying to solve a practical problem here...
For example:?
?
- Given a dynamic (moving coil) microphone like the Shure SM58,
- To be used with a Ham Radio like the Yaesu 900,
- The radio includes some signal processing/compression for the mic input,
- 48V Phantom power in not supplied per se, but 5VDC is available on the mic connector,
- The radio assumes a balanced mic input and has a 600ohms Zin,
- The SM58 has a Zout of 300ohms,
- According to the SM58 wiring diagram, the mic cartridge uses a transformer interface to the XLR connector.
- So, is a preamp needed in such an application and, if so, what kind of preamp?
Any help here is appreciated.
TIA,
Dan?
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What about grounding the unused channel?
Le 24/02/2025 à 01:01, Casey via
groups.io a écrit?:
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Hey all -- I have a project I'm working on that involves a
raspberry pi, a , and a
small electret capsule () powered from that
interface via PiP.
Everything works, but there is 60Hz mains hum.
I believe the the audio interface is providing a stereo 1/8"
jack, but it mixes to mono internally - the computer is only
provided a mono capture by the audio interface. (If I use a
different set of stereo PiP mics that I made which are wired to
a stereo plug, there is no hum, and both capsules hear audio in
the result, but the overall signal is weak.)
The mic capsule is wired to a stereo plug (using shielded lav
cable), but the signal only goes to one channel of that plug, so
I presume the disconnected channel is just feeding in hum, is
mixed with the signal in the interface, and that explains the
hum in the result.
Does my diagnosis sound correct? If so, what would you
recommend? Should I just wire the signal from the mic to both
the tip and sleeve of the plug, or will that mess up the
interaction with the capsule somehow? Or would it be smarter to
get a mono plug?
Thanks!
-Casey
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Equivalent to a mono plug would be connecting ring and sleeve together on the stereo plug.? So you could try that.? If it seems to change the signal level from the microphone, change the direct connection to a resistor (say around 10k ohms).
-Scott
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On 2/23/25 18:01, Casey via groups.io wrote:
Hey all -- I have a project I'm working on that involves a raspberry pi, a cheap USB audio interface <>, and a small electret capsule (JLI-61A <>) powered from that interface via PiP.
Everything works, but there is 60Hz mains hum.
I believe the the audio interface is providing a stereo 1/8" jack, but it mixes to mono internally - the computer is only provided a mono capture by the audio interface. (If I use a different set of stereo PiP mics that I made which are wired to a stereo plug, there is no hum, and both capsules hear audio in the result, but the overall signal is weak.)
The mic capsule is wired to a stereo plug (using shielded lav cable), but the signal only goes to one channel of that plug, so I presume the disconnected channel is just feeding in hum, is mixed with the signal in the interface, and that explains the hum in the result.
Does my diagnosis sound correct? If so, what would you recommend? Should I just wire the signal from the mic to both the tip and sleeve of the plug, or will that mess up the interaction with the capsule somehow? Or would it be smarter to get a mono plug?
Thanks!
-Casey
--
---- Scott Helmke ---- scott@... ---- (734) 604-9340 ----
"I have ceased distinguishing between the religious and the secular,
for everything is holy" - Joe Henry
|
Hey all -- I have a project I'm working on that involves a
raspberry pi, a , and a small electret capsule ()
powered from that interface via PiP.
Everything works, but there is 60Hz mains hum.
I believe the the audio interface is providing a stereo 1/8"
jack, but it mixes to mono internally - the computer is only
provided a mono capture by the audio interface. (If I use a
different set of stereo PiP mics that I made which are wired to a
stereo plug, there is no hum, and both capsules hear audio in the
result, but the overall signal is weak.)
The mic capsule is wired to a stereo plug (using shielded lav
cable), but the signal only goes to one channel of that plug, so I
presume the disconnected channel is just feeding in hum, is mixed
with the signal in the interface, and that explains the hum in the
result.
Does my diagnosis sound correct? If so, what would you recommend?
Should I just wire the signal from the mic to both the tip and
sleeve of the plug, or will that mess up the interaction with the
capsule somehow? Or would it be smarter to get a mono plug?
Thanks!
-Casey
|
Re: Windows XP installation disk
Am Fr., 21. Feb. 2025 um 03:44?Uhr schrieb Cram via <mitchell.cram= [email protected]>:
You can turn the nag screen off for activations - it's worked for me when using xp on a virtual machine (I too have had to run legacy software in the past).
Not necessarily exactly what you asked, but should point you in the correct direction. There are plenty of xp ISO downloads on legit sites (you've never really needed an "authentic MS disc").??
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Re: Windows XP installation disk
You can turn the nag screen off for activations - it's worked for me when using xp on a virtual machine (I too have had to run legacy software in the past).
Not necessarily exactly what you asked, but should point you in the correct direction. There are plenty of xp ISO downloads on legit sites (you've never really needed an "authentic MS disc").??
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Windows XP installation disk
Does anyone have a Windows XP install disk they could give or sell me? ?Or a copy with the password decrypted.
?
I need a pukka XP machine to run the software I wrote myself in da last Millenium. ?Yes. ?I've tried the various Virtual machines but none of them give me the functionality I need. ?To put this into perspective, I run a DOS window under Win 98 on the XP machine.
?
Machines that have XP drivers are all more than 10 yrs old. ?I found one but I lent my pukka XP install disc to a friend who promptly lost it?? ?
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Re: Circuit for PiP EM272
thank you everyone for clearing things up.
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Re: PCB for ambisonic mic with 9V power supply
Yes - sorry about the typo!? The ones I used are definitely the JLI-140A-T.
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Re: PCB for ambisonic mic with 9V power supply
On Wed, Feb 19, 2025 at 03:42 PM, David Platt wrote:
The guts now consist of four JLI-240A-T capsules
Do you mean JLI-140A-T capsules? I have a few of those. They're nice.
?
Thanks for sharing your circuit.
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Re: PCB for ambisonic mic with 9V power supply
See the attached ZIP (KiCAD 8 project with schematic and board layout, Gerbers, and a PDF of the schematic).? It might be suitable for you to use, either as-is or as a starting point for changes.?
?
A couple of years ago I was gifted with a "long past its use-by date" Philips stereo microphone.? The old dynamic elements were (I decided) quite useless by modern standards, and the foam had turned to goo and powder, but the shielded enclosure and stand were nicely built and in great shape.? I decided to experiment, gut it, and rebuilt it as a full-field microphone.
?
The guts now consist of four JLI-240A-T capsules, glued into a 3D-printed holder I built using OpenSCAD.? It's based on a basic pattern I found here in MicBuilders, with a graceful branching Bezier-curve support structure which fits into the screw-locked metal shaft in the microphone base.
?
I decided I did want a proper phantom-powered balanced drive for it, so I implemented one of the standard two-transistor circuits using a small PC-board layout (.86" wide by 1.26" long).? This is small enough that I could place four of them around the support shaft, wire them to the mics and to four (Electronics Flea Market surplus) XLR cables, and fit everything comfortably inside the case and shield.? I laid out the boards to suit the parts I had on hand - all surface-mount except for the two 1 uF film capacitors, for which I used through-hole parts I had handy.? I'm sure the boards could be made smaller, using SMT caps and 0805 or 0603 resistors.? I used BC856 transistors because I had a bunch of them in a samples box;? there are many other types which should work fine.
?
OshPark delivered 6 boards, in about two weeks, for under $11... hard to beat!
?
The result - it works, and with the shield closed there's no detectable hum pickup.? I got distracted by other projects and haven't done anything more than confirm the mic's basic functionality, but considering that it's using a standard sort of circuit and decent capsules I don't expect that there are any horrible surprises waiting (he said, walking confidently towards a cliff :-) )
?
?
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Re: Circuit for PiP EM272
Hi
Everything is fine with + capsule on + jack and ground capsule on ground jack.
The assembly of the technical sheet is already inside the recorder
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Re: PCB for ambisonic mic with 9V power supply
No need to duplicate requests.
SimpleP48 is adequate for balanced lines of less than 20 meters.
Does not require PCB's.
Le 18/02/2025 à 13:01, martenberger92
via groups.io a écrit?:
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Hi all,
I'd like to build a first order ambisonic 9V electret
microphone, that I can travel with.
Balanced outputs is important since I will need cable lengths of
6m and longer.
What are the smallest form factor PCBs available for a project
like this?
Are there any SMD based circuits openly available?
Thanks and I wish you all a lovely day!
M
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Re: Circuit for PiP EM272
The Sony PCM10, as well as all other products that provide PIP,
include the protection capacitor and resistor.
Addding them would not have any benefit.
Le 18/02/2025 à 10:34, dampfus.hansus
via groups.io a écrit?:
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Hello fellow mic builders,
I've soldered some cables to the EM272 capsules, with + to
signal and GND to GND. My Sony PCM M10 provides 3V of PiP.?
?
Should I also solder in the circuit from the data sheet, with
a resistor from GND to Signal and a capacitor to the Mic in?
If so what are the benefits? Is it true that I could damage
the recorder through not filtering the DC voltage?
?
Thank you very much!?
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Re: Circuit for PiP EM272
PIP power already has the resistor and capacitor internally. You don't?need to add them, just?plug it in to the Sony and you should?be good.?
Jules
On Tue, Feb 18, 2025 at 5:29?AM dampfus.hansus via <dampfus.hansus= [email protected]> wrote: Hello fellow mic builders,
I've soldered some cables to the EM272 capsules, with + to signal and GND to GND. My Sony PCM M10 provides 3V of PiP.?
?
Should I also solder in the circuit from the data sheet, with a resistor from GND to Signal and a capacitor to the Mic in?
If so what are the benefits? Is it true that I could damage the recorder through not filtering the DC voltage?
?
Thank you very much!?
-- Best Regards,
Jules Ryckebusch
214 399 0931
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PCB for ambisonic mic with 9V power supply
Hi all,
I'd like to build a first order ambisonic 9V electret microphone, that I can travel with.
Balanced outputs is important since I will need cable lengths of 6m and longer.
What are the smallest form factor PCBs available for a project like this?
Are there any SMD based circuits openly available?
Thanks and I wish you all a lovely day!
M
|
Hello fellow mic builders,
I've soldered some cables to the EM272 capsules, with + to signal and GND to GND. My Sony PCM M10 provides 3V of PiP.?
?
Should I also solder in the circuit from the data sheet, with a resistor from GND to Signal and a capacitor to the Mic in?
If so what are the benefits? Is it true that I could damage the recorder through not filtering the DC voltage?
?
Thank you very much!?
|
Re: Lom usi circuit vs simple P48
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Hey! Sorry I saw your message now. Yes I would love to trade, which primo capsules you have? I'm mostly interested in large diagram condenser ones, but I'm open to possibilities.
How many capsules do you need? I think I have 4 spares?
Let me know!?
If I don't answer you quickly, please send me a mail at ninmiso@....Bye!
-Simone
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Re: Lom usi circuit vs simple P48
EM272 and EM273 appear to be exactly the same element with a
different wiring. The 2-wire version has higher sensitivity,
because of the gain of the FET in common-source mode, when the
lower sensitivity of the 3-wire version is the result of the FET
being used in common-drain mode.
In simpleP48, the circuit is common-source, so there should be
little difference between a native 2-wire capsule and a 3-wire.
However, the Jerry Lee variant allows decreasing gain at teh
benefit of max SPL.
This can be done only with a 3-wire capsule (or a Linkwitz
modified).
Le 14/02/2025 à 20:55, kennjava a
écrit?:
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The Primo EM273 is similar to the EM272 but with higher SPL
handling (135 dB vs 119 dB). Also, the simpleP48 doc has a few
ideas about increasing the SPL headroom of some capsules.
?
The LOM basicUcho have a slightly different capsule mounting
(flush, vs the slight rim of the Clippy case), which might
account for some of the sound difference. I always flush-mount
the omni capsules in my mics.
?
?
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underwood
Muninn