Re: Microphone Output Impedance
?
Actually
?
MR-PRO ->? potentiometer? ->? ?Mic? -> Preamp
Pin 1? ? ? ?->? ? ? ? ? ?GND? ? ? ? ? ->? ?GND -> GND
Pin 2? ? ? ?->? ? ? ? ? ? ?R1? ? ? ? ? ? ->
Pin 3? ? ? ?->? ? ? ? ? ? ?R2? ? ? ? ? ? ->
?
?
MR-PRO Pin 1 connect GND.
?
Should I disconnect pin 1 of the MR-PRO?
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Re: Microphone Output Impedance
Actually, the wiring should be that:
Make sure that nothing is connected to Pin1 of minirator.
Le 24/01/2025 à 03:52, kandoit7 via
groups.io a écrit?:
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?
Dear
Jerry,
?
Hello.
In the meantime, my answer was late because I was preparing
for the experimental environment.
?
I
made it with reference to the circuit diagram you gave me. I
just changed the resistance of R1 and R2 to potentiometer.
?
?
Generator?
? : NTi Audio MR-PRO
Microphone
: Earthworks M23R
Preamp?
? ? ?: RME OctaMIC II
Analyzer?
? ? : NTi Audio Fx100
?
A
value measured without a resistance connection.
?
?
It
is a value that is later reduced by 6 dB.
?
?
At this point, the value of the resistance is
R1 : 69.5 Ohm
R2 : 66.8 Ohm .
?
The specific of the M23R provided on the homepage is 65Ω
balanced (between pins 2 & 3).
?
I think there is an error in the result value, but is it
normal that the values of R1 and R2 are originally similar?
?
And it seems that M23R product is not balanced. When M23R
is connected directly to MR-PRO, the R value for pin 2 is:86
Ohm, and the R value for pin 3 is:260 Ohm. For normal balanced
microphone, the resistance values for pin 2 and pin 3 are the
same.
Even in this situation, I wonder if the above measurement
method can be applied.
?
I would like to know your thoughts based on this result.
?
I'm currently looking for a reliable microphone to measure
other microphones.
I'll show you the results as soon as it goes.
?
Thank you.
?
I'm late to say hello, but happy new year.
?
Best Regards,
Kandoit7
|
Re: Microphone Output Impedance
?
Dear Jerry,
?
Hello. In the meantime, my answer was late because I was preparing for the experimental environment.
?
I made it with reference to the circuit diagram you gave me. I just changed the resistance of R1 and R2 to potentiometer.
?
?
Generator? ? : NTi Audio MR-PRO
Microphone : Earthworks M23R
Preamp? ? ? ?: RME OctaMIC II
Analyzer? ? ? : NTi Audio Fx100
?
A value measured without a resistance connection.
?
?
It is a value that is later reduced by 6 dB.
?
?
At this point, the value of the resistance is
R1 : 69.5 Ohm
R2 : 66.8 Ohm .
?
The specific of the M23R provided on the homepage is 65Ω balanced (between pins 2 & 3).
?
I think there is an error in the result value, but is it normal that the values of R1 and R2 are originally similar?
?
And it seems that M23R product is not balanced. When M23R is connected directly to MR-PRO, the R value for pin 2 is:86 Ohm, and the R value for pin 3 is:260 Ohm. For normal balanced microphone, the resistance values for pin 2 and pin 3 are the same.
Even in this situation, I wonder if the above measurement method can be applied.
?
I would like to know your thoughts based on this result.
?
I'm currently looking for a reliable microphone to measure other microphones.
I'll show you the results as soon as it goes.
?
Thank you.
?
I'm late to say hello, but happy new year.
?
Best Regards,
Kandoit7
|
Re: SMD transistors for Alice/Schoeps
Jack, practically ANY small signal 'LN' pnp will do.
?
I have a liking for 'small' power stuff like Jerry & jp8 but the rest of your circuit must be super for this to have even 0.1dB effect on noise.
?
Higher voltage devices allow you to use plain 1n914/4148 instead of Zeners across them.? But don't leave the diodes out as their most important task is to protect the b-e junctions.
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Re: SMD transistors for Alice/Schoeps
And it also has the best Hfe matching, btw.
?
I always pair the BCM53DS with a BCM56DS (NPN pair) to form a? CFP output for reduced THD and improved CMRR.
?
Jan
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Re: SMD transistors for Alice/Schoeps
BCM53DS seems particularly interesting, since it has a large
geometry (related to the 1A max current).
Quite often, these medium-power transistors have very low noise at
currents of about 1-2 mA, although manufacturers don't advertise
it. If they did, they would have to QC it, which adds to the cost.
Le 20/01/2025 à 08:00, j.postma8 via
groups.io a écrit?:
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[Edited Message Follows]
My favourite PNPs for the output stage are the Nexperia
BCM53DS and BCM857DS.
?
Double, factory matched pair. No more hand picking of pairs
with matching Vbe and Hfe required.
?
Jan
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Re: SMD transistors for Alice/Schoeps
My favourite PNPs for the output stage are the Nexperia BCM53DS and BCM857DS.
?
Double, factory matched pair. No more hand picking of pairs with matching Vbe and Hfe required.
?
Jan
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Re: SMD transistors for Alice/Schoeps
You could but I highly recommend the simple P48 if you need to go really small. It works really well. Best Regards,
Jules Ryckebusch?
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On Jan 19, 2025, at 17:47, jack via groups.io <jackreynolds100@...> wrote:
? Can you use the opamp circuit with electrets with built in FETs?
07889727365
02036861372
3 Swimmers Lane
Haggerston
London
E2 8FR
On Sun, 19 Jan 2025 at 22:51, Jules Ryckebusch via <ryckebusch= [email protected]> wrote: Sadly that one is obsolete with through hole ones still available. I’ve switched everything over to the OPA circuit.
Best Regards,
Jules Ryckebusch
> On Jan 19, 2025, at 16:43, jack via <jackreynolds100=[email protected]> wrote:
>
> 2N5087
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Re: SMD transistors for Alice/Schoeps
Can you use the opamp circuit with electrets with built in FETs?
07889727365
02036861372
3 Swimmers Lane
Haggerston
London
E2 8FR
On Sun, 19 Jan 2025 at 22:51, Jules Ryckebusch via <ryckebusch= [email protected]> wrote: Sadly that one is obsolete with through hole ones still available. I’ve switched everything over to the OPA circuit.
Best Regards,
Jules Ryckebusch
> On Jan 19, 2025, at 16:43, jack via <jackreynolds100=[email protected]> wrote:
>
> 2N5087
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Re: SMD transistors for Alice/Schoeps
Heh.? Haven't looked that circuit in a while, I guess. 2N5087 is the PNP output stage.
Same thing applies, though - probably a lot of transistors will work just fine, I've done this on other things where I had to substitute a new part.
-Scott
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On 1/19/25 16:53, Scott Helmke wrote: I was doing PF5102 to replace the on5087, but those are also EOL.
You could just try collecting all the major specs from the PF5102 and plugging those into the search on Mouser or Digi-Key.? I don't think anything is really going to be magic anymore, modern FETs are very good.
-Scott
On 1/19/25 16:43, jack via groups.io wrote:
Hi All,
Happy new year (if it’s not too late to say it!)
Any thoughts on SMD replacements (or improvements!) on the through hole 2N5087?
I’m looking to squeeze eight or more circuits onto a single board, so the smaller the better.
Any ideas greatly received
? Cheers
Jack
--
---- Scott Helmke ---- scott@... ---- (734) 604-9340 ----
"I have ceased distinguishing between the religious and the secular,
for everything is holy" - Joe Henry
|
Re: SMD transistors for Alice/Schoeps
I was doing PF5102 to replace the on5087, but those are also EOL.
You could just try collecting all the major specs from the PF5102 and plugging those into the search on Mouser or Digi-Key.? I don't think anything is really going to be magic anymore, modern FETs are very good.
-Scott
toggle quoted message
Show quoted text
On 1/19/25 16:43, jack via groups.io wrote: Hi All,
Happy new year (if it’s not too late to say it!)
Any thoughts on SMD replacements (or improvements!) on the through hole 2N5087?
I’m looking to squeeze eight or more circuits onto a single board, so the smaller the better.
Any ideas greatly received
Cheers
Jack
--
---- Scott Helmke ---- scott@... ---- (734) 604-9340 ----
"I have ceased distinguishing between the religious and the secular,
for everything is holy" - Joe Henry
|
Re: SMD transistors for Alice/Schoeps
Sadly that one is obsolete with through hole ones still available. I’ve switched everything over to the OPA circuit.
Best Regards,
Jules Ryckebusch
toggle quoted message
Show quoted text
On Jan 19, 2025, at 16:43, jack via groups.io <jackreynolds100@...> wrote:
2N5087
|
SMD transistors for Alice/Schoeps
Hi All,
Happy new year (if it’s not too late to say it!)
Any thoughts on SMD replacements (or improvements!) on the through hole 2N5087?
I’m looking to squeeze eight or more circuits onto a single board, so the smaller the better.
Any ideas greatly received
Cheers
Jack
|
Re: short pickup range options
Could one of the following capsules that PUI released last year be a good starting point to DIY something?
?
According to PUI’s new product announcement it states:
These new microphones find applications in various settings where
targeted sound capture is important. For example, these will perform exceptionally
well in automotive applications, consumer applications such as broadcasting,
conference rooms or headsets.
?
For more details have a look at the product announcement.
?
?
On Thu, Jan 16, 2025 at 08:20 PM, Richard Lee wrote:
Anyone interested to DIY something with similar performance?
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Re: short pickup range options
There's a BBC monograph about modifying a Reslo ribbon mic to improve the bass response. in the process of assessing the model they determined that the fine weave cloth gauze was contributing to lower LF response which was removed because air velocity was not considered a risk in a studio environment.?
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Re: short pickup range options
In case it isn't obvious, the 4104 is STILL SOTA for its job.
?
Anyone interested to DIY something with similar performance?
?
We want a cardioid or Fig 8 with REALLY CRAP LF response to modify so I'm not surprised that Heinz got good results from his CM-2S.? From Fig 6 of the BBC Monograph, LF -3dB cutout should be about 3kHz :o
?
We could modify an omni electret to make a crap cardioid or Fig 8 but a cheapo dynamic vocal mike/capsule might be easier.
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Re: short pickup range options
The coles lip mic used by football commentators is a figure 8 ribbon mic. the HF from the rear is actually better than from the front because of all the pop filters and spit catchers that are put on the front. the main benefit from it is that it's side rejection is excellent so you don't get the commentator next to you bleeding into your contribution. the local crowd noise is being projected away from you, the other crowd noise is distant and even if the commentators box is in the middle of the stand you are a physical barrier to audio because you place the mic's guard on your philtrum to speak (being loud to hear yourself think which helps with the output which still needs about 50dB of gain . written down it doesn't sound like it would work but side rejection and the inverse square law is what makes them so good even if journalists manage to break them somehow.?
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Re: short pickup range options
It's really amazing what you guys can conjure up from the depths of the microphone builder drawer. I'm impressed and delighted! ?
?
What I’m missing is that @cx b (clistburnham) didn’t mention what kind of sounds he would like to record on an extremely short pickup range? How short is extremely short? But maybe that’s not relevant.
?
This is my short story about recording sounds from close range in a noob way.
A few years ago a friend of mine asked me if I could record and provide all sorts of bicycle sound effects and nature sounds for his bicycle game that was in development at the time. Since I had no experience in this field, I focused intensively on Foley recording and sound design, and how to achieve good results. I read many interesting articles and watched a lot of insightful videos from some of the best Foley artists in the world. It was fantastic to get a little glimpse behind the scenes.
As you may have guessed. What I was missing was a well-equipped Foley studio, professional studio equipment and many years of experience in this field. :-) Anyway, I wanted to help my friend and started experimenting with the equipment I had: A Sony PCM M10, an audio interface and a few microphones that I collected over the years.
One of the videos that helped me a lot was created by David Farmer, the Sound Designer of Lord of the Rings Sound Effects (LOTR). In case anyone is interested, he documented some of the .
The first two minutes of his instruction video “” and his recording tips starting at 09:25 pointed me in the right direction. Many thanks, David!
I tried to record the bicycle sound effects with the PCM M10 alone, but it turned out that the background ambiance was still too dominant to remove it from the recording in post-production without creating unpleasant artifacts. So I tested every single microphone I had with the PCM M10 at close range and ended up recording many of the bike sound effects with a vintage microphone originally designed for recording on reel-to-reel-tape recorders. A Pioneer CM-2S unidirectional stereo condenser. I used only one channel of the CM-2S, pointed at the sound source of interest at close range. To my ears this combination produced the best result with almost no background noise when recording bicycle sound effects. Here are the specifications of the CM-S2:
Dual element electret condenser unit
Hypercardioid pattern
Response: 20-20,000 Hz
Output impedance: 1000 ohms
Sensitivity: -68 dB at 1 kHz (0 dB = 1 V/? bar)
Maximum SPL: 126 dB
S/N: 46 dB;?
1.5-V "AAA" cell power supply
6.06" H x 4.33" W
Weight: 11.2 ounces
21 -ft cable
Pair comes mounted on desk stand.
?
I was able to integrate many of the mono recordings into the three-dimensional sound space of the bike game and it sounded beautiful as we rode through the game. Unfortunately, the game is on hold because priorities have shifted somewhat. That's it!
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Re: short pickup range options
There's other juju too.? IIRC, there is a BBC
Engineering Monograph which details the
design of this iconic beast.? Please post if you find a link to
this document.
This might be a more permanent link:
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Re: short pickup range options
There's other juju too.? IIRC, there is a BBC
Engineering Monograph which details the
design of this iconic beast.? Please post if you find a link to
this document.
This one?
|
