Re: Microphone output impedance
Thanks Jerry, I thought it was 1K. I worked in Marketing for a decade... Medical Devices. And there was the FDA... ;-)
Jules
On Sun, Feb 2, 2025 at 10:07?AM Jerry Lee Marcel via <jerryleemarcel= [email protected]> wrote:
Le 02/02/2025 ¨¤ 19:54, Jules Ryckebusch
via a ¨¦crit?:
Question for the
group on this. What is the?correct frequency to measure the
output impedance? I am assuming referenced to 1Khz.
In the absence of a comment saying different, impedances are
measured at 1kHz.
Or should?it be 20hz
to 20Khz?
Some manufacturers indicate that impedance may vary over the audio
range.
What do
manufacturers spec?
Anything the mktg dept deems valuable.
Seriously, some manufacturers specs are laughable.
I checked DPA's site
and they just list a value.
I've found that, although their designers are excellent, their
technical communication is far from being as good.
--
Best
Regards,
Jules
Ryckebusch
214 399 0931
-- Best Regards,
Jules Ryckebusch
214 399 0931
|
Re: Microphone output impedance
Le 02/02/2025 ¨¤ 19:54, Jules Ryckebusch
via groups.io a ¨¦crit?:
Question for the
group on this. What is the?correct frequency to measure the
output impedance? I am assuming referenced to 1Khz.
In the absence of a comment saying different, impedances are
measured at 1kHz.
Or should?it be 20hz
to 20Khz?
Some manufacturers indicate that impedance may vary over the audio
range.
What do
manufacturers spec?
Anything the mktg dept deems valuable.
Seriously, some manufacturers specs are laughable.
I checked DPA's site
and they just list a value.
I've found that, although their designers are excellent, their
technical communication is far from being as good.
--
Best
Regards,
Jules
Ryckebusch
214 399 0931
|
Microphone output impedance
Question for the group on this. What is the?correct frequency to measure the output impedance? I am assuming referenced to 1Khz. Or should?it be 20hz to 20Khz? What do manufacturers spec? I checked DPA's site and they just list a value.
-- Best Regards,
Jules Ryckebusch
214 399 0931
|
I'm trying to get in touch with David Searle, aka Zephyr on MicBuilders.
?
David, if you are still looking in occasionally, the email address I have for your no longer works.
?
My old email address no longer works either :(? So please use this one to reply
?
Richard Lee
aka
Ricardo
ricardo_lee@...
?
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Re: Microphone Output Impedance
Dear Jerry,?
?
Thanks to your reply.
?
Earthworks Homepage's M23R Spec :
?
OUTPUT IMPEDANCE ? ?65¦¸ balanced (between pins 2 & 3)
?
This is the specification provided on the website.
What I mean here is not the Symmetric impedance between Pin 2 and Pin 3?
I think R1 + R2 = Symmetric impedance.
?
If so, 130 Ohm would be the output impedance, but I wonder if Earthworks is providing 65 Ohm.
?
haha, Thanks to you, I am building up my knowledge.
?
Best Regards,
Kandoit7
|
Re: Microphone Output Impedance
It seems correct, indicating a mic impedance of about 130 ohms.
Le 02/02/2025 ¨¤ 06:25, kandoit7 via
groups.io a ¨¦crit?:
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Dear
Jerry,
?
I¡¯m
still getting similar results.
R1 : 66 Ohm
R2 : 65 Ohm
Here¡¯s my question:
I¡¯m using a single potentiometer to control both channels (R1
and R2), meaning adjusting it changes both values to nearly
the same resistance.
?
Should
I instead use separate potentiometers for R1 and R2 to adjust
them independently?
?
This
comes up because when I directly connected the M23R to the
MR-PRO, the microphone¡¯s impedance measurements showed
imbalance.?
?
Best
Regards,?
Kandoit7
|
Re: Microphone Output Impedance
Dear Jerry,
?
I¡¯m still getting similar results.
R1 : 66 Ohm
R2 : 65 Ohm
Here¡¯s my question:
I¡¯m using a single potentiometer to control both channels (R1 and R2), meaning adjusting it changes both values to nearly the same resistance.
?
Should I instead use separate potentiometers for R1 and R2 to adjust them independently?
?
This comes up because when I directly connected the M23R to the MR-PRO, the microphone¡¯s impedance measurements showed imbalance.?
?
Best Regards,?
Kandoit7
|
Hello there,
I was looking to buy some TSB/JLI-2590 Capsules but couldnt find any to ship here to germany with reasonable shipping costs. Micboosters charges 17 pounds for shipping and I paid over 30 euros for import tax the last time i bought from them. JLI charges over 50 bucks (wth...) so theyre out of the question too.?
I then came across listings for 2501 and 2502 capsules on ebay. The 2502s look like the 2590 but without the pcb and the 2501 look exactly like the tsb2590. Its a bit sketchy as all the pictures of them on every website are exactly the same. I found a listing on aliexpress for 11 bucks per capsule and i payed about 5 bucks for shipping.: so I ordered a few.
Im still a bit sketched out because I couldnt find anything about them on the Internet except for these listings. Has anyone ever heard of these capsules? Are they a clone of the 2590s? The Measurements look to be about the same between them. Any feedback would be appreciated.
|
Re: Microphone Output Impedance
Le 25/01/2025 ¨¤ 01:16, kandoit7 via
groups.io a ¨¦crit?:
?
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?
Yes.
|
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?
|
Re: Microphone Output Impedance
Actually, the wiring should be that:
Make sure that nothing is connected to Pin1 of minirator.
Le 24/01/2025 ¨¤ 03:52, kandoit7 via
groups.io a ¨¦crit?:
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Show quoted text
?
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 65¦¸
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 65¦¸ 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.
|
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
|
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 ¨¤ 08:00, j.postma8 via
groups.io a ¨¦crit?:
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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
|
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
|
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
|
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
|
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
|
