I was going to add - solder a jumper between pin 1 and the shield on the XLR to ensure the preamp casing and the cable shield are continuous.
I have has to do this several times where a mic will sound great when plugged into my recorder running on batteries, but buzzes like hell when you plug the power supply in.
Jack
toggle quoted message
Show quoted text
On 10 Jul 2024, at 13:58, Richards via groups.io <jrichards@...> wrote:
?. . . I still hear the hum although it seems to be lower) . . .
_________________________________________________________
Notwithstanding my rookie status, considering the fact the hum comes and goes jockeying the connectors ... I sorta, kinda, almost, maybe, possibly suspect what is termed the "Pin 1" problem, which you can read about here: Jim Brown K9YC is an AES guy with loads of funky ideas, some of which may be correct:
Also maybe see info and links to articles here:
I have found this sort of issue pop up in all sorts of situations, especially wiring microphones to amateur radio transceivers, sometimes requiring the cable shield to be linked to the connector case and, also therefore, equipmenent chassis, and sometimes not, it is a mixed bag - working in some cases, other times making it worse - but I figure it may be related ... or not ... remember I AM still a rookie!
Just thinking aloud out of turn ... James K8JHR
|
. . . I still hear the hum although it seems to be lower) . . .
_________________________________________________________
Notwithstanding my rookie status, considering the fact the hum comes and goes jockeying the connectors ... I sorta, kinda, almost, maybe, possibly suspect what is termed the "Pin 1" problem, which you can read about here: Jim Brown K9YC is an AES guy with loads of funky ideas, some of which may be correct:
Also maybe see info and links to articles here:
I have found this sort of issue pop up in all sorts of situations, especially wiring microphones to amateur radio transceivers, sometimes requiring the cable shield to be linked to the connector case and, also therefore, equipmenent chassis, and sometimes not, it is a mixed bag - working in some cases, other times making it worse - but I figure it may be related ... or not ... remember I AM still a rookie!
Just thinking aloud out of turn ... James K8JHR
|
Re: Strange Simple P48 readings with new EM272 caps
Thanks Jerry,? I just assumed [I know it makes an ass of you and me] that as the specs were supposedly the same for the 172, that the 272 would be a straight swap in the circuit.? I've just tested with a 5% 47K¦¸ resistor and there was something more like 5v across the cap, but the voltage seemed to rise slowly over time. I've ordered a range of 1% resistors?in that sort of ballpark so will experiment with them and see what I can do to get the V closest to 7V. I assume that when they are in their 'happy zone' the matching should shine through?
Kind regards Ade
With 0.19V across the capsules, they operate far from their
expected op point. Then it's not unusual to see degradation of
performance.
You must first find why the voltage is incorrect.
The value of 150k seems somewhat questionable to me.
The nominal current for the EM272 is 600uA, but with 150kohms,
the current cannot be higher than 320uA.
The fact that some capsules work fine with such a low current
doesn't guarantee that all capsules would work with that.
I think you'll have to decrease the value of the resistor until
you find a proper operating point.
That's one of the limits of the otherwise clever Simple P48.
Le 09/07/2024 ¨¤ 23:09, Adrian Hicks a
¨¦crit?:
Apologies the PNG had alpha background so rendered
wrong.
On Tue, Jul 9, 2024, 22:02
Adrian Hicks < mail@...>
wrote:
Picking back up with the Primo capsules. I
managed to lose one of the EM172 in a gap in the loft floor,
so bought some EM272s.
Today I wired them up but there was a weird
discrepancy of about 5dB between the two of them (They
were both plugged into XLR ports on a MixPre6ii with pan L
and R and both set to 50dB of gain). So I stopped and went
back and checked everything was as it should be. The
capsules were a matched pair, both resistors are reading
149.9K and they are wired as in the image below. As I've
learned from the previous responses, the FET forms part of
the circuit, so to ascertain that both capsules were
getting the same voltage I probed them with the DMM, This
is where it becomes more weird. Now I am seeing 0.19v on
both no way near the expected 5V. Even accounting for the
low voltage it doesn't explain how there is a 5dB
difference between the two of them.
My question is two-fold;?
1. How using 4u7F Al caps correctly
polarised, and 150k 1% resistors am I getting 0.19v across
the +/- terminals on the capsules?
2. What could explain the 5dB difference
between the two capsules? The capsules came from
Micbooster, who I trust implicitly.
Apologies for my lack of knowledge...
On Mon, Mar 18, 2024,
15:29 kennjava < ken@...>
wrote:
On
Sun, Mar 17, 2024 at 11:20 AM, Adrian Hicks wrote:
So, am I correct in thinking that this is
basically a resistor divider? With the FET being one of
the resistances in the system?
Sort of, but that's an incomplete explanation.
Would I measure the resistance across the capsule
in order to get the third value?
NO. The FET in the capsule is part of an active circuit;
you can't just "measure the resistance" with an ohmmeter
across the pins of a capsule.
?I've probably just opened a can of worms for
myself by trying to optimise something that has worked
for years, but I suppose it is all good learning.
It's both. The simpleP48 document is both a foolproof
recipe, and a pretty good explanation of how it works.
To get more into it, you could read up on .
|
Re: Strange Simple P48 readings with new EM272 caps
With 0.19V across the capsules, they operate far from their
expected op point. Then it's not unusual to see degradation of
performance.
You must first find why the voltage is incorrect.
The value of 150k seems somewhat questionable to me.
The nominal current for the EM272 is 600uA, but with 150kohms,
the current cannot be higher than 320uA.
The fact that some capsules work fine with such a low current
doesn't guarantee that all capsules would work with that.
I think you'll have to decrease the value of the resistor until
you find a proper operating point.
That's one of the limits of the otherwise clever Simple P48.
Le 09/07/2024 ¨¤ 23:09, Adrian Hicks a
¨¦crit?:
toggle quoted message
Show quoted text
Apologies the PNG had alpha background so rendered
wrong.
On Tue, Jul 9, 2024, 22:02
Adrian Hicks < mail@...>
wrote:
Picking back up with the Primo capsules. I
managed to lose one of the EM172 in a gap in the loft floor,
so bought some EM272s.
Today I wired them up but there was a weird
discrepancy of about 5dB between the two of them (They
were both plugged into XLR ports on a MixPre6ii with pan L
and R and both set to 50dB of gain). So I stopped and went
back and checked everything was as it should be. The
capsules were a matched pair, both resistors are reading
149.9K and they are wired as in the image below. As I've
learned from the previous responses, the FET forms part of
the circuit, so to ascertain that both capsules were
getting the same voltage I probed them with the DMM, This
is where it becomes more weird. Now I am seeing 0.19v on
both no way near the expected 5V. Even accounting for the
low voltage it doesn't explain how there is a 5dB
difference between the two of them.
My question is two-fold;?
1. How using 4u7F Al caps correctly
polarised, and 150k 1% resistors am I getting 0.19v across
the +/- terminals on the capsules?
2. What could explain the 5dB difference
between the two capsules? The capsules came from
Micbooster, who I trust implicitly.
Apologies for my lack of knowledge...
On Mon, Mar 18, 2024,
15:29 kennjava < ken@...>
wrote:
On
Sun, Mar 17, 2024 at 11:20 AM, Adrian Hicks wrote:
So, am I correct in thinking that this is
basically a resistor divider? With the FET being one of
the resistances in the system?
Sort of, but that's an incomplete explanation.
Would I measure the resistance across the capsule
in order to get the third value?
NO. The FET in the capsule is part of an active circuit;
you can't just "measure the resistance" with an ohmmeter
across the pins of a capsule.
?I've probably just opened a can of worms for
myself by trying to optimise something that has worked
for years, but I suppose it is all good learning.
It's both. The simpleP48 document is both a foolproof
recipe, and a pretty good explanation of how it works.
To get more into it, you could read up on .
|
... Have you accessed the driver to make level adjustments, as described in the manual? Try plugging headphones directly into the mic, to see what that's like.
Here's a review, with some tips about application, if you haven't already seen it.
Thanks, I remember reading that review a while ago, it rings a bell, but I checked it again just in case. And plugging headphones directly doesn't seem to have any noise, but I think it's just because either mic gain is too low, or my headphone's impedance is too high (or low, still learning about all of this :D), or both. Also, level adjustments on the "driver" (Windows side of things, basically) doesn't seem to change anything, Reaper doesn't seem to notice what I change there (only input level and format available).
Anyway, after "fixing" the issue (I'm not completely sure it's fixed, I still hear the hum although it seems to be lower) the new noise for the mic is -67db, which I'm not sure if it's expected, good, bad or what... I feel there is more that can be done to reduce that hum even more, but -67db is much better than -50db :)
|
Re: Strange Simple P48 readings with new EM272 caps
Apologies the PNG had alpha background so rendered wrong.
On Tue, Jul 9, 2024, 22:02 Adrian Hicks < mail@...> wrote: Picking back up with the Primo capsules. I managed to lose one of the EM172 in a gap in the loft floor, so bought some EM272s. Today I wired them up but there was a weird discrepancy of about 5dB between the two of them (They were both plugged into XLR ports on a MixPre6ii with pan L and R and both set to 50dB of gain). So I stopped and went back and checked everything was as it should be. The capsules were a matched pair, both resistors are reading 149.9K and they are wired as in the image below. As I've learned from the previous responses, the FET forms part of the circuit, so to ascertain that both capsules were getting the same voltage I probed them with the DMM, This is where it becomes more weird. Now I am seeing 0.19v on both no way near the expected 5V. Even accounting for the low voltage it doesn't explain how there is a 5dB difference between the two of them. My question is two-fold;? 1. How using 4u7F Al caps correctly polarised, and 150k 1% resistors am I getting 0.19v across the +/- terminals on the capsules? 2. What could explain the 5dB difference between the two capsules? The capsules came from Micbooster, who I trust implicitly.
Apologies for my lack of knowledge...
On Mon, Mar 18, 2024, 15:29 kennjava < ken@...> wrote: On Sun, Mar 17, 2024 at 11:20 AM, Adrian Hicks wrote:
So, am I correct in thinking that this is basically a resistor divider? With the FET being one of the resistances in the system?
Sort of, but that's an incomplete explanation.
Would I measure the resistance across the capsule in order to get the third value?
NO. The FET in the capsule is part of an active circuit; you can't just "measure the resistance" with an ohmmeter across the pins of a capsule.
?I've probably just opened a can of worms for myself by trying to optimise something that has worked for years, but I suppose it is all good learning.
It's both. The simpleP48 document is both a foolproof recipe, and a pretty good explanation of how it works.
To get more into it, you could read up on .
|
Re: Strange Simple P48 readings with new EM272 caps
Picking back up with the Primo capsules. I managed to lose one of the EM172 in a gap in the loft floor, so bought some EM272s. Today I wired them up but there was a weird discrepancy of about 5dB between the two of them (They were both plugged into XLR ports on a MixPre6ii with pan L and R and both set to 50dB of gain). So I stopped and went back and checked everything was as it should be. The capsules were a matched pair, both resistors are reading 149.9K and they are wired as in the image below. As I've learned from the previous responses, the FET forms part of the circuit, so to ascertain that both capsules were getting the same voltage I probed them with the DMM, This is where it becomes more weird. Now I am seeing 0.19v on both no way near the expected 5V. Even accounting for the low voltage it doesn't explain how there is a 5dB difference between the two of them. My question is two-fold;? 1. How using 4u7F Al caps correctly polarised, and 150k 1% resistors am I getting 0.19v across the +/- terminals on the capsules? 2. What could explain the 5dB difference between the two capsules? The capsules came from Micbooster, who I trust implicitly.
Apologies for my lack of knowledge...
On Mon, Mar 18, 2024, 15:29 kennjava < ken@...> wrote: On Sun, Mar 17, 2024 at 11:20 AM, Adrian Hicks wrote:
So, am I correct in thinking that this is basically a resistor divider? With the FET being one of the resistances in the system?
Sort of, but that's an incomplete explanation.
Would I measure the resistance across the capsule in order to get the third value?
NO. The FET in the capsule is part of an active circuit; you can't just "measure the resistance" with an ohmmeter across the pins of a capsule.
?I've probably just opened a can of worms for myself by trying to optimise something that has worked for years, but I suppose it is all good learning.
It's both. The simpleP48 document is both a foolproof recipe, and a pretty good explanation of how it works.
To get more into it, you could read up on .
|
On Tue, Jul 9, 2024 at 07:38 AM, Edu Garcia wrote:
About that driver you mention, do you have any links about that?
The driver is mentioned in the 3rd paragraph of your link:
... it does not say "custom", and you're right, the manual only refers to a default driver. Have you accessed the driver to make level adjustments, as described in the manual? Try plugging headphones directly into the mic, to see what that's like.
, if you haven't already seen it.
|
Ok, so just as a bit of an update, as I was getting ready to disassemble it I decided to make a few more tests. I connected it, and suddenly got no noise (after getting noise for hours yesterday). I thought it was because now I'm in my office instead of another random place of the house, but when I touched the cable, the noise came back. Long story short, it seems the connector is faulty. I can twist it a few times and sometimes the noise disappears, not even in the exact same spot, it's just random. I can also make it disappear if I manually connect the connector shielding with the USB shield (just tried putting one of my keys in the connector :D), so yeah, there is maybe a cracked solder joint or something similar inside, I'll have to open and deal with it.
Thanks again to everybody offering suggestions, really appreciate it.
|
It does sound very much like a lack of grounding issue. Laptop power supplies tend to be a bit dodgy with regard to grounding in the first place, but with nothing connected you have no ground at all. If you were to ground yourself you would make the noise reduce by touching the mic, but ungrounded you're kind of a big antenna yourself.
Thanks Scott. One of the tests I did was connecting my charger, but it made the problem a bit worse, which I also didn't understand, as the charger would be grounding the laptop, but I'll try directly grounding myself and see what changes :).
In general, USB mics do not hum, because the connection is digital. However, it may be that there is a floating ground connection.
First, I would try another USB cable, then test the mic with another computer.
For the sake of verification, you may want to add a wire between teh mic body and the computer chassis.
Thanks Jerry. I doubt it's the cable, it's brand new and used it with other mics with better success, but it's a good point to test that assumption. Same with testing on another computer and finally testing with a wire between both, although the USB cable should have that connection made, but of course anything can happen with cheap electronics :D.
If that were my mic, I would take it apart, look for damaged or poor connections, especially connections to the case, and maybe for power rail electrolytic capacitors that could have failed. But I've been doing this for over 55 years. :-)
Please try your mic on different computers and in different places to see if the hum occurs everywhere. Also, this mic apparently requires a custom driver to control its gain. Do you have that installed?
Thanks kennjava, I'd definitely take it apart and check, but I obviously don't have the experience to know what to look for (although I dabble in Arduinos and things like that), but I can definitely post some photos and maybe you or somebody else can point where there might be a potential fault. About that driver you mention, do you have any links about that? I haven't found anything on the manual or any search regarding "drivers" anywhere on the official site.
Again, thank you all for your time.
|
If that were my mic, I would take it apart, look for damaged or poor connections, especially connections to the case, and maybe for power rail electrolytic capacitors that could have failed. But I've been doing this for over 55 years. :-)
Please try your mic on different computers and in different places to see if the hum occurs everywhere. Also, this mic apparently requires a custom driver to control its gain. Do you have that installed?
|
In general, USB mics do not hum, because the connection is
digital. However, it may be that there is a floating ground
connection.
First, I would try another USB cable, then test the mic with
another computer.
For the sake of verification, you may want to add a wire between
teh mic body and the computer chassis.
Le 09/07/2024 ¨¤ 11:13, Edu Garcia a
¨¦crit?:
toggle quoted message
Show quoted text
Hello there, first message on the forum and hopefully this is
the right place for this kind of questions.
I have an Audio-Technica ATR2500-USB mic (),
had it since release around 12 or 13 years ago, but always
sounded very low so didn't use it much. Yesterday I picked it up
again to see what the problem was, and found that while the
volume is actually adequate (much less sensitive than other mics
I have though), it picks up a hum from mains (I've recorded and
confirmed it's a sine of ~50Hz) that behaves in a strange way,
at least to me, so I'm hoping for at least an explanation, but
even better for theories on what to do about it.
I connected the mic to my laptop and no other cables anywhere,
not even the charger or anything else. I can hear the hum very
faintly (noise between -60db to -55db according to Reaper). With
my laptop on my lap and me sitting on a couch or a chair, if I
put my feet on the floor, the noise gets noticeable louder
(around -48db). If I actually touch the mic with my hands (it
has an aluminum body), the noise becomes very loud and distorted
(gets up to -12db), at this point it doesn't really matter if I
touch the floor or not.
I'm assuming this is due to some grounding issues, but from
what I've read online about people having similar problems with
other kind of mics, they get better results instead of
worse when touching the mic (i.e. the noise goes away). I'll try
to get better pictures today, but somebody took these that might
already show something to a trained eye:
Does anybody have a theory of what might be happening? I know
there is probably not enough info here for a true diagnostic,
but even if I cannot fix it, I'd like to know what's happening.
And of course, being able to fix it will be nice, if just for
the fact that I spent a lot of money at some point and will be
nice to use it for something before keeping it in a
closet for another 13 years :).
Thanks in advance for any tips, really appreciate it.
|
It does sound very much like a *lack of* grounding issue. Laptop power supplies tend to be a bit dodgy with regard to grounding in the first place, but with nothing connected you have no ground at all. If you were to ground yourself you would make the noise reduce by touching the mic, but ungrounded you're kind of a big antenna yourself.
-Scott
toggle quoted message
Show quoted text
On 7/9/24 04:13, Edu Garcia wrote:
Hello there, first message on the forum and hopefully this is the right place for this kind of questions.
I have an /Audio-Technica ATR2500-USB/ mic (), had it since release around 12 or 13 years ago, but always sounded very low so didn't use it much. Yesterday I picked it up again to see what the problem was, and found that while the volume is actually adequate (much less sensitive than other mics I have though), it picks up a hum from mains (I've recorded and confirmed it's a sine of ~50Hz) that behaves in a strange way, at least to me, so I'm hoping for at least an explanation, but even better for theories on what to do about it.
I connected the mic to my laptop and no other cables anywhere, not even the charger or anything else. I can hear the hum very faintly (noise between -60db to -55db according to Reaper). With my laptop on my lap and me sitting on a couch or a chair, if I put my feet on the floor, the noise gets noticeable louder (around -48db). If I actually touch the mic with my hands (it has an aluminum body), the noise becomes very loud and distorted (gets up to -12db), at this point it doesn't really matter if I touch the floor or not.
I'm assuming this is due to some grounding issues, but from what I've read online about people having similar problems with other kind of mics, they get /better/ results instead of worse when touching the mic (i.e. the noise goes away). I'll try to get better pictures today, but somebody took these that might already show something to a trained eye:
Does anybody have a theory of what might be happening? I know there is probably not enough info here for a true diagnostic, but even if I cannot fix it, I'd like to know what's happening. And of course, being able to fix it will be nice, if just for the fact that I spent a lot of money at some point and will be nice to use it for /something/ before keeping it in a closet for another 13 years :).
Thanks in advance for any tips, really appreciate it.
--
---- Scott Helmke ---- scott@... ---- (734) 604-9340 ----
"I have ceased distinguishing between the religious and the secular,
for everything is holy" - Joe Henry
|
Hello there, first message on the forum and hopefully this is the right place for this kind of questions.
I have an Audio-Technica ATR2500-USB mic (), had it since release around 12 or 13 years ago, but always sounded very low so didn't use it much. Yesterday I picked it up again to see what the problem was, and found that while the volume is actually adequate (much less sensitive than other mics I have though), it picks up a hum from mains (I've recorded and confirmed it's a sine of ~50Hz) that behaves in a strange way, at least to me, so I'm hoping for at least an explanation, but even better for theories on what to do about it.
I connected the mic to my laptop and no other cables anywhere, not even the charger or anything else. I can hear the hum very faintly (noise between -60db to -55db according to Reaper). With my laptop on my lap and me sitting on a couch or a chair, if I put my feet on the floor, the noise gets noticeable louder (around -48db). If I actually touch the mic with my hands (it has an aluminum body), the noise becomes very loud and distorted (gets up to -12db), at this point it doesn't really matter if I touch the floor or not.
I'm assuming this is due to some grounding issues, but from what I've read online about people having similar problems with other kind of mics, they get better results instead of worse when touching the mic (i.e. the noise goes away). I'll try to get better pictures today, but somebody took these that might already show something to a trained eye:
Does anybody have a theory of what might be happening? I know there is probably not enough info here for a true diagnostic, but even if I cannot fix it, I'd like to know what's happening. And of course, being able to fix it will be nice, if just for the fact that I spent a lot of money at some point and will be nice to use it for something before keeping it in a closet for another 13 years :).
Thanks in advance for any tips, really appreciate it.
|
Re: Another DIY AOM5024 with SimpleP48 experiment
The SimpleP48 while excellent in most other aspects, is very dependent on having absolutely clean phantom power if you need it to be hum free. Most mixers have some ripple on the phantom supply. Because of the unbalanced current draw of SimpleP48, that ripple is not cancelled out by the balanced mic preamp.
With my Zoom R24 the high level of hum makes it completely unusable with SimpleP48. No problem with other types of microphone.
With my Mackie mixer there is a low level hum, only a problem on really quiet sources. If I turn off phantom power on the Mackie, the hum goes away and the Simple P48 is hum free and works perfect for a while until the phantom supply capacitors gets slowly drained.
|
Re: How can add 80Hz LF to SimpleP48 circuit?
As Jerry has advised, reducing the capacitor reduces some of the deep bass. In some of my adaptors I've made that capacitance switchable so that I can drop some bass when it's excessive or unnecessary.
But it's a gentle rolloff, not sharp. If you're looking for a sharper cutoff to eliminate your hum issue, you'd need to design a sharper filter, or use the HP filters built into your recorder or interface. Or tackle problem frequencies after, with a parametric EQ in your audio editor.
|
Re: DIY Panasonic WM-61A capsule with audio isolation transformer (from Shin's PA workshop)
Hi Adam,
Thanks for the updates.
I mainly use my mics outside, feeding a portable recorder with XLR inputs. I also currently have two PUI AOM5024, wired as simpleP48, "permanently"mounted outside, in our back yard, with about 40 ft (12 meters) of inexpensive shielded balanced wire (similar to your West Penn wire) running in our house to a USB audio interface that has phantom-powered balanced mic inputs. I haven't encountered any AC hum, or other interference in any of those situations.
This is what I suggest: make more tests with your simpleP48 mics, in different locations, to get a better idea of what circumstances lead to hum. Also try different devices if you can, like other recorders or interfaces, and borrow some commercial balanced mics, including ones with and without transformers, and try them in the same location, over the same wire, to see if they also have hum issues. Theaters can be difficult environments because of electronic noise from light dimmers.
And how long were your mic cables in the theater situation that gave you hum?? The simpleP48 arrangement is surprisingly good, but it's not perfectly, symmetrically balanced, so it might be more susceptible to interference in difficult situations, and/or runs of over 10 m.
|
Another DIY AOM5024 with SimpleP48 experiment
Hello Everyone,
With the information I learned from this forum and elsewhere, I also tried a PuiAudio AOM5024 + SimpleP48 circuit. The recording noise is extremely low and the sound quality is very good, but I have some "hum" noise to deal with...
These are what I did:
1. A Heat Shrink Tubing was covered the capsule (AOM5024) and the copper tape wrapped on shrink tubing, copper tape soldered to shield pair on the cable and directly goes to XLR connector. The pressed and shaped as mic capsule metal grill mesh insulation piece was also put on the head of the capsule and it does not touch the capsule but connected to copper tape and cable shield. On the outside, a shrink tube was used to wrap it all. I used multi-turn potentiometer in XLR connection part for first time testing the best voltage for capsule.
2. ?West Penn Wire 25291B was used as the cable (actually I also had Mogami W2697, but I didn't use Mogami for the first test, because I thought there was not too much difference between them, maybe I'm wrong :) )
3. I also used the Neutrik NC3MXX-EMC Cable Connector as a XLR connector, but then the supply voltage of the microphone dropped to 3.1 volts, so I gave up using it...
As an Audio interface-mixer, I used Allen & Heath Qu-16C, Audient EVO 4, M-Audio AIR 192.
I would like to thank everyone who shares knowledge-info-experience with us in the group, Knowledge is nice when it is shared :)
I look forward to your comments...
Best,
|
Re: DIY Panasonic WM-61A capsule with audio isolation transformer (from Shin's PA workshop)
Hello Everyone,
Many thanks for feedback, I'll check everything again...
These are what I did:
1. A Heat Shrink Tubing was covered the capsule (AOM5024) and the copper tape wrapped on shrink tubing, copper tape soldered to shield pair on the cable and directly goes to XLR connector. The pressed and shaped as mic capsule metal grill mesh insulation piece was also put on the head of the capsule and it does not touch the capsule but connected to copper tape and cable shield. On the outside, a shrink tube was used to wrap it all. I used multi-turn potentiometer in XLR connection part for first time testing the best voltage for capsule.
2.? West Penn Wire 25291B was used as the cable (actually I also had Mogami W2697, but I didn't use Mogami for the first test, because I thought there was not much difference between them, maybe I'm wrong :) )
3. I also used the Neutrik NC3MXX-EMC Cable Connector as a XLR connector, but then the supply voltage of the microphone dropped to 3.1 volts, so I gave up using it...
As an Audio interface-mixer, I used Allen & Heath Qu-16C, Audient EVO 4, M-Audio AIR 192
The noise of recording with AOM5024 is really really low, I liked it.
Best,
|
Re: DIY Panasonic WM-61A capsule with audio isolation transformer (from Shin's PA workshop)
--
Gesendet mit der Mail App
Am 07.07.24, 11:28 schrieb "underwood via groups.io" <underwood.de.vu@...>:
toggle quoted message
Show quoted text
In some cases, hum is due to cheap or bad cables. A longer cable often pic up more hum then?the capsule.
Am So., 7. Juli 2024 um 10:53?Uhr schrieb Jerry Lee Marcel via <jerryleemarcel= [email protected]>:
[Quote]What I want to focus on is whether it would be advantageous to use an Audio isolation transformer. I also use the SimpleP48 circuit (I used it for two theater events at our school). But although it depends on the type of Audio interface used, there is a 60Hz hum in the recorded sound. I wonder if we can eliminate this by using an isolation transformer? [/Quote]
In most cases, hum is due to improper shielding of the capsule. Using a transformer? doesn't solve the issue.
|
Mic Scharf