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Re: Specs for old Transsound capsules?

 

¿ªÔÆÌåÓý

You can't use "voltage-divider calculation", because the FET in the capsule does not act as a resistor. It has a variable I/V characteristic. Actually, most FET's used in low-level electronics are used in their "pentode" mode, which is very close to a constant-current sink.

Le 20/09/2024 ¨¤ 22:37, A Van Der Reijden via groups.io a ¨¦crit?:

Jerry Lee Marcel wrote: As with any buitlt-in FET capsule, one has to experiment.
?
I'm sure it is due to my ignorance that I'm puzzled: as soon as you know (from the specs.) that a capsule loves to see i.e. 8 volts, it's just a matter of following the outcome of a voltage divider calculation, et voil¨¤, you know exactly what resistor you have to use? End of the experiment?
Re: Specs for old Transsound capsules?

 

There's no "exactly" the resistance value to use. There is usually a range of resistor values within which the capsule performs acceptably well. And there's variation capsule-to-capsule. Yes, if you're keen, you can conduct further experiments to find the absolute sweet spot for each individual capsule that maximizes dynamic range while still being a safe operating point, but you need a deeper understanding of the FET circuit, some test equipment, and time.?
?
Read the excellent writeup in the simpleP48 documentation, and in the discussions here about simpleP48 powering. These give more insight on how to determine suitable resistor values.
?
When I had some new capsules to use, I followed those guidelines to determine a resistance, and I also paid attention to not exceeding either the voltage or current max specs of the capsule, which I measured as I experimented.?
?
Did I find the one absolutely optimum resistor value? Don't know, don't care. The current and voltage are at safe levels, and the mics perform just fine for the mostly low level field sounds that I record. If I encountered higher noise, or distortion at an undesirably low peak level, because my chosen operating point was too far off, I would have to pick a better value.
Re: Specs for old Transsound capsules?

 

Jerry Lee Marcel wrote: As with any buitlt-in FET capsule, one has to experiment.
?
I'm sure it is due to my ignorance that I'm puzzled: as soon as you know (from the specs.) that a capsule loves to see i.e. 8 volts, it's just a matter of following the outcome of a voltage divider calculation, et voil¨¤, you know exactly what resistor you have to use? End of the experiment?
Re: Specs for old Transsound capsules?

 

¿ªÔÆÌåÓý

All these capsules indicate identical test conditions, 2V with a 2.2kohm resistor. It does not give any indication of what the resistor should be with a different voltage.
As with any buitlt-in FET capsule, one has to experiment.
Considering the value of 0.5mA for the maximum current indicates that the resistor Rx for a different voltage Vx should be no less than

Rx>(Vx-2)/0.0005, which, for 9V results in
Rx>7/0.0005 or 14kohm

I would recommend starting with a higher value, like 27k, and while measuring the voltage across the capasule, adjust the resistor until the voltage reaches about 5V.
Of course, you would note that no capsule has the same optimum resistor, but it shouldn't be too difficult to find a value that works for all. That's how it's done by mic designers.



Le 20/09/2024 ¨¤ 03:44, Heinz a ¨¦crit?:

Hi Mike
?
The specs of the capsules you mentioned can still be found in the Internet Archives Wayback Machine. Unfortunately, it does not show the images of the frequency response curve, the schematic diagram, the image of the capsule itself, or the dimensions.
?
?
?
?
?
Hope this helps!
?
Heinz
?
On Fri, Sep 20, 2024 at 06:02 AM, Scott Helmke wrote:
spec sheets for this old Transsound capsules
Re: Specs for old Transsound capsules?

 

Hi Mike
?
The specs of the capsules you mentioned can still be found in the Internet Archives Wayback Machine. Unfortunately, it does not show the images of the frequency response curve, the schematic diagram, the image of the capsule itself, or the dimensions.
?
?
?
?
?
Hope this helps!
?
Heinz
?
On Fri, Sep 20, 2024 at 06:02 AM, Scott Helmke wrote:

spec sheets for this old Transsound capsules
Re: Specs for old Transsound capsules?

 

¿ªÔÆÌåÓý

Hi Mike,

You could try calling JLI, their number is 215-256-3200.? They carried the whole line at one point.

-Scott

On 9/19/24 15:56, Mike Feldman wrote:
Two decades ago I was an active DIYer and built a couple binaural heads, some PZMs, and other projects.? About the time Panasonic was discontinuing the WMxx (61?? See, it's been that long), I ordered a bunch of capsules to play with, I think from JMI, but it might have been a group buy that Bob Cain put together.

Now I have a use for a 9mm electret capsule, and I've got this package with some TS-94A capsules, and also some TSB-9445A and TS-52B.? What I don't have (at least not on any hard drives I have spinning, or useful results from that once search engine, now ad flyer Google) are spec sheets for those capsules.

I remember enough to put together a 9v battery, a ??K resistor, and a DC blocking cap, but I'd like to get the resistor value close on the 1st try.

Does anyone have spec sheets for this old Transsound capsules, or a link to them?

Thanks much,
Mike

-- 
---- Scott Helmke ---- scott@... ---- (734) 604-9340 ----
"I have ceased distinguishing between the religious and the secular,
for everything is holy"  - Joe Henry
Specs for old Transsound capsules?

 

Two decades ago I was an active DIYer and built a couple binaural heads, some PZMs, and other projects.? About the time Panasonic was discontinuing the WMxx (61?? See, it's been that long), I ordered a bunch of capsules to play with, I think from JMI, but it might have been a group buy that Bob Cain put together.

Now I have a use for a 9mm electret capsule, and I've got this package with some TS-94A capsules, and also some TSB-9445A and TS-52B.? What I don't have (at least not on any hard drives I have spinning, or useful results from that once search engine, now ad flyer Google) are spec sheets for those capsules.

I remember enough to put together a 9v battery, a ??K resistor, and a DC blocking cap, but I'd like to get the resistor value close on the 1st try.

Does anyone have spec sheets for this old Transsound capsules, or a link to them?

Thanks much,
Mike
Re: Learning about amplifiers

 

"The Art of Electronics" is the best PRACTICAL book on Electronics.? The reason it is so large is that it takes you all the way from Ohm's Law to Guru level assuming only basic Arithmetic.
?
Adrian, I recommend you start at Chapter 1 and work your way through. Stop anywhere you like.? Not everyone needs to be a Guru.? But if you become a Guru in your old age, you will still come back to TAOE for further insights.
?
There's a workbook that goes with it that might help you with the discipline of studying a new art.
?
I also second Andy's suggestion to learn to use LTspice.? Try it out on the type of circuits you want to understand.
Re: Learning about amplifiers

 

Here is great resource from my Navy Days??

And the entire library.?
This is where my initial?electronics training came?from many moons ago...?

Jules

On Tue, Sep 17, 2024 at 2:40?PM Paul Doornbusch via <paul.doornbusch=[email protected]> wrote:
I do not have a book or website to recommend except perhaps Rod Elliot¡¯s, but what you seem to want is an understanding of the various basic single-stage amplifier types, such as common emitter, common base, common collector, and then the fundamentals of different devices such as BJTs, JFETs (depletion mode and enhancement mode), MOSFETs, and so on.?

Then you want to be able to look at a complex schematic and break it down into functional blocks. To keep this on track a typical mic amplifier has an impedance converter to go from the extremely high impedance of the capsule to a low impedance that is capable of driving more circuitry without attracting EM interference, and then a low impedance drive stage to drive a cable of several metres and the input impedance of a preamp. You might also have a circuit to provide a 50V-200V polarisation voltage for the capsule if it is not an electret.

There have been various historical technologies used which still today influence the choices made, such as transformers in microphone preamps (which allowed ¡°phantom¡± power to be used for microphones, so some of the modern circuits seek to provide optimum performance in a real world where some parts of the signal chain may not be optimised for current technology.

I hope this helps!


On 17 Sep 2024, at 20:11, Adrian Hicks via <mail=[email protected]> wrote:

Of course, I was more looking for recommendations on the best materials.?
I had considered an online course, but not wanting to become an electronics engineer I didn't really know what would be the best option.
Hill and Horowitz seems to be a Bachelors degree in a book, but it's just the size of it that makes it seem insurmountable. I suppose I just need to break down into the actual elements I really need to learn.?
I.e ohms and Kirchoff's laws and then move on from there.
I think being a mechanical engineer is a curse, because anything you don't understand means that you now 'need' to understand it.

On Tue, 17 Sept 2024, 19:02 Jules Ryckebusch, <ryckebusch@...> wrote:
lol that is more than an email ?.? Let me see what references I can find.?
Best Regards,

Jules Ryckebusch?

On Sep 17, 2024, at 13:54, Adrian Hicks via??<mail=[email protected]> wrote:

?
The basics of how they work.
I've looked at your designs and from other conversations on here seen other schematics.
I'd like to be able to read a schematic. Currently I can only work out the most basic elements such as filtering caps and voltage dividers but not the whole schematic.?
It's analogous to being given a map but not having the ability to read it but being able to see the destination on it.


On Tue, 17 Sept 2024, 18:50 Jules Ryckebusch, <ryckebusch@...> wrote:
What are you wanting to learn in reference to them? I have built a few and just finished a 12 channel build.? I lot has shifted in the past 20 years specifically the use of Class D. My build used LM3886 chips?
Best Regards,

Jules Ryckebusch?

On Sep 17, 2024, at 13:42, Adrian Hicks via??<kartparts=[email protected]> wrote:

?
I¡¯ve been looking around to try to find some sources of material to enable me to learn about how amplifiers work.?
I¡¯ve only got the most rudimentary electronics knowledge so end up floundering very quickly.?
I bought The Art of Electronics a while ago and have had a cursory browse through it.

I was also recommended this paper by an old work colleague.


"Audio power amplifier design" has also been recommended to me.

What do you guys think / recommend to enable learning about these things? It seems that a lot of you are well versed in the ways of coercing electrons







--
Best Regards,

Jules Ryckebusch

214 399 0931
Re: Learning about amplifiers

 

Another vote for The Art of Electronics which would have made life a lot easier when I was at college 50 years ago.?
The well thumbed books on the shelf include National Semis Linear Applications Handbook and their Intuitive IC Op Amps, and the applications notes section of Analog Devices Audio/Video Reference Manual.? Manufacturer's application notes themselves can be a good source of information even if some leave out the critical bits such as decoupling caps.
If you want to see how circuits (might) work before physically building them SPICE is a great tool.? I use LTSPICE which has schematic entry, test point probing and graph plotting; there are component libraries available from manufacturers if you want to move on from ideal opamps to real parts.?
Andy
Re: Linkwitz to ground/source/drain

 

Exactly what I was looking for, thank you!
Re: Linkwitz to ground/source/drain

 

More info. than I can handle ;>) - very helpful, thank you.
Re: Linkwitz to ground/source/drain

 

¿ªÔÆÌåÓý

Although it's generally the contrary that is asked (modding a 2-wre into a 3-wire), it is quite easy to do.

Just connect the source to ground.

Another possibility is to connect a resistor between source and ground.

That decreases sensitivity, but it also increases max SPL capability and decreases distortion.

A typical value is 2.2kohm but actually the value depends very much on the FET and the desired change.

Le 18/09/2024 ¨¤ 12:02, A Van Der Reijden via groups.io a ¨¦crit?:

Is there a way to connect a 3 pad electret (ground/source/drain) to the Linkwitz 2 wire solution? Thank you!
Re: Linkwitz to ground/source/drain

 

Does this give you the information you need?


And?

? around half way down

Craig


------ Original Message ------
From "A Van Der Reijden via groups.io" <avdreijden@...>
Date 18/09/2024 11:02:24
Subject [MicBuilders] Linkwitz to ground/source/drain

Is there a way to connect a 3 pad electret (ground/source/drain) to the Linkwitz 2 wire solution? Thank you!
Linkwitz to ground/source/drain

 

Is there a way to connect a 3 pad electret (ground/source/drain) to the Linkwitz 2 wire solution? Thank you!
Re: Learning about amplifiers

 

I've done a lot of the stuff I shouldn't be able to. I built a high altitude balloon tracker and managed to write the code to .make it parse gps strings and transmit them using RTTY.
I designed the PCB for that and got it all working.
Ive done PCBs from schematics and got them made and they all work. One of which was the high Z amp that jules did for the hydrophones (it was far cheaper than just the shipping from JLI to the UK for 50 boards).
Maybe I should take a step back and just do things on a breadboard so I can tweak and play with things.
I bought 5 of those caps I posted about the other day for about 60p each. So I have a source of things I'm not scared to fry.
The art of electronics does look good, I think I need to employ the mountaineers trick of breaking the book (mountain) down into smaller parts, rather than looking at the sheer enormity of it and running away as ever.
The opamp pdf also looks like a good course in itself that goes from the very basics.
Maybe those two are all I really need.?

On Tue, 17 Sept 2024, 21:13 kennjava, <ken@...> wrote:
"The Art of Electronics" is absolutely worth having. True story : while I was struggling in Electrical Engineering (its almost all calculus, and i suck at calculus),? my friend in Physics took a one term electronics course that went straight to all the practical every-day transistor design stuff that I was dying to learn, and "The Art of Electronics" was their text. Op-amps are vital audio building blocks, so be sure to spend time with those.
?
Rod Elliot's circuits are also very useful, as well as Paul's advice here. And I believe there are some decent free electronics courses online. So it is possible to learn from basic principles and go up.
?
It's also possible to go in the other direction: find a project you like, build it, and then spend some time learning about how that circuit actually works (and how you could tweak it). A lot of useful hacking is done these days just by using an IC or module as a black box.
Re: Learning about amplifiers

 

"The Art of Electronics" is absolutely worth having. True story : while I was struggling in Electrical Engineering (its almost all calculus, and i suck at calculus),? my friend in Physics took a one term electronics course that went straight to all the practical every-day transistor design stuff that I was dying to learn, and "The Art of Electronics" was their text. Op-amps are vital audio building blocks, so be sure to spend time with those.
?
Rod Elliot's circuits are also very useful, as well as Paul's advice here. And I believe there are some decent free electronics courses online. So it is possible to learn from basic principles and go up.
?
It's also possible to go in the other direction: find a project you like, build it, and then spend some time learning about how that circuit actually works (and how you could tweak it). A lot of useful hacking is done these days just by using an IC or module as a black box.
Re: Learning about amplifiers

 

¿ªÔÆÌåÓý

I do not have a book or website to recommend except perhaps Rod Elliot¡¯s, but what you seem to want is an understanding of the various basic single-stage amplifier types, such as common emitter, common base, common collector, and then the fundamentals of different devices such as BJTs, JFETs (depletion mode and enhancement mode), MOSFETs, and so on.?

Then you want to be able to look at a complex schematic and break it down into functional blocks. To keep this on track a typical mic amplifier has an impedance converter to go from the extremely high impedance of the capsule to a low impedance that is capable of driving more circuitry without attracting EM interference, and then a low impedance drive stage to drive a cable of several metres and the input impedance of a preamp. You might also have a circuit to provide a 50V-200V polarisation voltage for the capsule if it is not an electret.

There have been various historical technologies used which still today influence the choices made, such as transformers in microphone preamps (which allowed ¡°phantom¡± power to be used for microphones, so some of the modern circuits seek to provide optimum performance in a real world where some parts of the signal chain may not be optimised for current technology.

I hope this helps!


On 17 Sep 2024, at 20:11, Adrian Hicks via groups.io <mail@...> wrote:

Of course, I was more looking for recommendations on the best materials.?
I had considered an online course, but not wanting to become an electronics engineer I didn't really know what would be the best option.
Hill and Horowitz seems to be a Bachelors degree in a book, but it's just the size of it that makes it seem insurmountable. I suppose I just need to break down into the actual elements I really need to learn.?
I.e ohms and Kirchoff's laws and then move on from there.
I think being a mechanical engineer is a curse, because anything you don't understand means that you now 'need' to understand it.

On Tue, 17 Sept 2024, 19:02 Jules Ryckebusch, <ryckebusch@...> wrote:
lol that is more than an email ?.? Let me see what references I can find.?
Best Regards,

Jules Ryckebusch?

On Sep 17, 2024, at 13:54, Adrian Hicks via??<mail=[email protected]> wrote:

?
The basics of how they work.
I've looked at your designs and from other conversations on here seen other schematics.
I'd like to be able to read a schematic. Currently I can only work out the most basic elements such as filtering caps and voltage dividers but not the whole schematic.?
It's analogous to being given a map but not having the ability to read it but being able to see the destination on it.


On Tue, 17 Sept 2024, 18:50 Jules Ryckebusch, <ryckebusch@...> wrote:
What are you wanting to learn in reference to them? I have built a few and just finished a 12 channel build.? I lot has shifted in the past 20 years specifically the use of Class D. My build used LM3886 chips?
Best Regards,

Jules Ryckebusch?

On Sep 17, 2024, at 13:42, Adrian Hicks via??<kartparts=[email protected]> wrote:

?
I¡¯ve been looking around to try to find some sources of material to enable me to learn about how amplifiers work.?
I¡¯ve only got the most rudimentary electronics knowledge so end up floundering very quickly.?
I bought The Art of Electronics a while ago and have had a cursory browse through it.

I was also recommended this paper by an old work colleague.


"Audio power amplifier design" has also been recommended to me.

What do you guys think / recommend to enable learning about these things? It seems that a lot of you are well versed in the ways of coercing electrons
Re: Learning about amplifiers

 

Of course, I was more looking for recommendations on the best materials.?
I had considered an online course, but not wanting to become an electronics engineer I didn't really know what would be the best option.
Hill and Horowitz seems to be a Bachelors degree in a book, but it's just the size of it that makes it seem insurmountable. I suppose I just need to break down into the actual elements I really need to learn.?
I.e ohms and Kirchoff's laws and then move on from there.
I think being a mechanical engineer is a curse, because anything you don't understand means that you now 'need' to understand it.

On Tue, 17 Sept 2024, 19:02 Jules Ryckebusch, <ryckebusch@...> wrote:
lol that is more than an email ?.? Let me see what references I can find.?
Best Regards,

Jules Ryckebusch?

On Sep 17, 2024, at 13:54, Adrian Hicks via <mail=[email protected]> wrote:

?
The basics of how they work.
I've looked at your designs and from other conversations on here seen other schematics.
I'd like to be able to read a schematic. Currently I can only work out the most basic elements such as filtering caps and voltage dividers but not the whole schematic.?
It's analogous to being given a map but not having the ability to read it but being able to see the destination on it.


On Tue, 17 Sept 2024, 18:50 Jules Ryckebusch, <ryckebusch@...> wrote:
What are you wanting to learn in reference to them? I have built a few and just finished a 12 channel build.? I lot has shifted in the past 20 years specifically the use of Class D. My build used LM3886 chips?
Best Regards,

Jules Ryckebusch?

On Sep 17, 2024, at 13:42, Adrian Hicks via <kartparts=[email protected]> wrote:

?
I¡¯ve been looking around to try to find some sources of material to enable me to learn about how amplifiers work.?
I¡¯ve only got the most rudimentary electronics knowledge so end up floundering very quickly.?
I bought The Art of Electronics a while ago and have had a cursory browse through it.

I was also recommended this paper by an old work colleague.


"Audio power amplifier design" has also been recommended to me.

What do you guys think / recommend to enable learning about these things? It seems that a lot of you are well versed in the ways of coercing electrons
Re: Learning about amplifiers

 

¿ªÔÆÌåÓý

lol that is more than an email ?. ?Let me see what references I can find.?
Best Regards,

Jules Ryckebusch?

On Sep 17, 2024, at 13:54, Adrian Hicks via groups.io <mail@...> wrote:

?
The basics of how they work.
I've looked at your designs and from other conversations on here seen other schematics.
I'd like to be able to read a schematic. Currently I can only work out the most basic elements such as filtering caps and voltage dividers but not the whole schematic.?
It's analogous to being given a map but not having the ability to read it but being able to see the destination on it.


On Tue, 17 Sept 2024, 18:50 Jules Ryckebusch, <ryckebusch@...> wrote:
What are you wanting to learn in reference to them? I have built a few and just finished a 12 channel build.? I lot has shifted in the past 20 years specifically the use of Class D. My build used LM3886 chips?
Best Regards,

Jules Ryckebusch?

On Sep 17, 2024, at 13:42, Adrian Hicks via <kartparts=[email protected]> wrote:

?
I¡¯ve been looking around to try to find some sources of material to enable me to learn about how amplifiers work.?
I¡¯ve only got the most rudimentary electronics knowledge so end up floundering very quickly.?
I bought The Art of Electronics a while ago and have had a cursory browse through it.

I was also recommended this paper by an old work colleague.


"Audio power amplifier design" has also been recommended to me.

What do you guys think / recommend to enable learning about these things? It seems that a lot of you are well versed in the ways of coercing electrons
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