The instructions are the same as the AmbiAlice ?you just make two capsule to XLR cables using the components mentioned ?? Best Regards,
Jules Ryckebusch?
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On Feb 8, 2024, at 11:52, Paul <wildlifesounds@...> wrote:
? Hi
I would be very grateful for some assistance please. I would like to make a simple 48V circuit version of the MS mics you mention above, using the JLI 160A11UC680 or the JLI-2590 mic capsules. (I am not able to get hold of the JLI-1660-nb-38 capsule here in the UK). Unfortunately my understanding of electronics is pretty minimal, I can follow a simple circuit diagram, but have no understanding of the ins and outs of electronics, so unfortunately I can¡¯t get my head around what goes to where or what connects to what. Please would it be possible to have a simple diagram showing XLR connecting to the 2 mics. And would using the same resistor (100K) and capacitor (3.3uf) in Ambi-Alice work, or do the values need to changing?
?
Many thanks
?
Paul Pratley
|
Hi
I would be very grateful for some assistance please. I would like to make a simple 48V circuit version of the MS mics you mention above, using the JLI 160A11UC680 or the JLI-2590 mic capsules. (I am not able to get hold of the JLI-1660-nb-38 capsule here in the UK). Unfortunately my understanding of electronics is pretty minimal, I can follow a simple circuit diagram, but have no understanding of the ins and outs of electronics, so unfortunately I can¡¯t get my head around what goes to where or what connects to what. Please would it be possible to have a simple diagram showing XLR connecting to the 2 mics. And would using the same resistor (100K) and capacitor (3.3uf) in Ambi-Alice work, or do the values need to changing?
?
Many thanks
?
Paul Pratley
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Re: Input protection for OPA1642 for Piezo use. Oh, and Humpback Whales
Thanks Arjay. This is from the Data Sheet:
"Input pins are diode-clamped to the power-supply rails. Input signals that can swing more than 0.5 V beyond the supply rails must be?current-limited to 10 mA or less. The input voltage and output negative-voltage ratings can be exceeded if the input and output current ratings are followed."I know about TVS protection but think it may be overkill here. The Schottky?diodes (Fingers Crossed on this?one) should keep the inputs below the supply rails?+ the .5 Volts. I plan on doing some robust testing over the next few days. The 1K should limit my transient current to far below the 10ma.?
I will keep the group posted.
Jules ?
On Wed, Feb 7, 2024 at 5:00?AM Arjay1949 < info@...> wrote: On Tue, Feb 6, 2024 at 01:45 PM, Jules Ryckebusch wrote:
I Just had a really cool adventure recording Humpbacks with my hydrophones. See this:?
?
One challenge was the failure of two of them post build.? I also had a couple board?failures after initial?testing of the boards?prior to attaching the Piezo cylinders. There were two modes of failure. Complete failure of the Opamp causing?a higher than normal current draw. Second, it still worked but with a lot of noise.? The light?bulb went off as I realised that I was directly connecting the cylinder to the Piezo element. I connected my Oscope to the cylinder and tapped on it. I could easily generate 15-20 volt spikes that were visible on the scope. Reviewing the literature, I realized I wasn't?including any input protection. Yes there are internal diodes for this in the opamp. I suspect they are fine for "normal use". I am updating the circuit as seen below:
![Protection.png]()
?
This includes a series resistor?and two diodes to shunt anything to ground and the supply pins. Conveniently there is a .1uF cap across the supply rails of the opamp that will act as a low Z source for this too.?
?
I have my first boards back from PCBWay and will commence testing shortly.?
?
Love any advice?or feedback here.?
?
--
Best Regards,
?
Jules Ryckebusch
?
214 399 0931
?
I was wondering if useg BAS40-04 diodes for protection might be pushing things right to the edge? .......
I'm guessing the offending piezo transients are quite high impedance - and no real current flows -
but the 380mV max voltage drop on for currents below 1mA seems very close to the OPA1642 absolute maximum input voltage limit.(Supply volts ¡À 0.5V)?
And if the current does rise above that level, then the forward voltage drop may exceed the absolute limit?
Might it be worth considering TVS protection instead?? ()
An appropriate device could be selected to keep well below the OPA1642 absolute limits...
(BTW, love the humpback video -- now that's what I call a?real nature recording project! :) )
??
-- Best Regards,
Jules Ryckebusch
214 399 0931
|
Re: Input protection for OPA1642 for Piezo use. Oh, and Humpback Whales
On Tue, Feb 6, 2024 at 01:45 PM, Jules Ryckebusch wrote:
I Just had a really cool adventure recording Humpbacks with my hydrophones. See this:?
?
One challenge was the failure of two of them post build.? I also had a couple board?failures after initial?testing of the boards?prior to attaching the Piezo cylinders. There were two modes of failure. Complete failure of the Opamp causing?a higher than normal current draw. Second, it still worked but with a lot of noise.? The light?bulb went off as I realised that I was directly connecting the cylinder to the Piezo element. I connected my Oscope to the cylinder and tapped on it. I could easily generate 15-20 volt spikes that were visible on the scope. Reviewing the literature, I realized I wasn't?including any input protection. Yes there are internal diodes for this in the opamp. I suspect they are fine for "normal use". I am updating the circuit as seen below:
?
This includes a series resistor?and two diodes to shunt anything to ground and the supply pins. Conveniently there is a .1uF cap across the supply rails of the opamp that will act as a low Z source for this too.?
?
I have my first boards back from PCBWay and will commence testing shortly.?
?
Love any advice?or feedback here.?
?
--
Best Regards,
?
Jules Ryckebusch
?
214 399 0931
?
I was wondering if useg BAS40-04 diodes for protection might be pushing things right to the edge? ....... I'm guessing the offending piezo transients are quite high impedance - and no real current flows - but the 380mV max voltage drop on for currents below 1mA seems very close to the OPA1642 absolute maximum input voltage limit.(Supply volts ¡À 0.5V)? And if the current does rise above that level, then the forward voltage drop may exceed the absolute limit? Might it be worth considering TVS protection instead?? () An appropriate device could be selected to keep well below the OPA1642 absolute limits... (BTW, love the humpback video -- now that's what I call a? real nature recording project! :) ) ??
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Re: Input protection for OPA1642 for Piezo use. Oh, and Humpback Whales
Hi Jules
Many thanks for sharing the video!
Yesterday I was (re)searching on the topic of bioacoustics and came across the following open access book that might be of interest to you.
Christine Erbe, Jeanette A. Thomas
Centre for Marine Science and Technology, Curtin University, Perth, WA, Australia
Springer Nature, 03.10.2022
The e-book is free and contains lots of useful information and references about different types of hydrophones and other topics:
I¡¯ve placed a copy in the library.
I'm sorry, but I can't give you any advice on board improvements.
?
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Re: Input protection for OPA1642 for Piezo use. Oh, and Humpback Whales
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Awesome thank you so much! Just read your publication on AES btw, great work!? On Tue, Feb 6, 2024 at 7:01?AM Jules Ryckebusch < ryckebusch@...> wrote: I am using?Schottky Diodes? 40V ones?? I based this on a EDN article on for input protection.
?
Hey there Jules, thank you for the update. I have put together many of your boards since you started with the opa Alice, and I have just started with the smaller piezo SMD boards, very lovely devices.?
I may be showing the green behind my ears but may I ask which diodes you are using in this update?
Thank you for all you do in this community.? On Tue, Feb 6, 2024 at 5:45?AM Jules Ryckebusch < ryckebusch@...> wrote: I Just had a really cool adventure recording Humpbacks with my hydrophones. See this:?
One challenge was the failure of two of them post build.? I also had a couple board?failures after initial?testing of the boards?prior to attaching the Piezo cylinders. There were two modes of failure. Complete failure of the Opamp causing?a higher than normal current draw. Second, it still worked but with a lot of noise.? The light?bulb went off as I realised that I was directly connecting the cylinder to the Piezo element. I connected my Oscope to the cylinder and tapped on it. I could easily generate 15-20 volt spikes that were visible on the scope. Reviewing the literature, I realized I wasn't?including any input protection. Yes there are internal diodes for this in the opamp. I suspect they are fine for "normal use". I am updating the circuit as seen below: 
This includes a series resistor?and two diodes to shunt anything to ground and the supply pins. Conveniently there is a .1uF cap across the supply rails of the opamp that will act as a low Z source for this too.?
I have my first boards back from PCBWay and will commence testing shortly.?
Love any advice?or feedback here.?
-- Best Regards,
Jules Ryckebusch
214 399 0931
--
Best Regards,
Jules Ryckebusch
214 399 0931
-- Best Regards,
Jules Ryckebusch
214 399 0931
|
Re: Input protection for OPA1642 for Piezo use. Oh, and Humpback Whales
Awesome thank you so much! Just read your publication on AES btw, great work!?
On Tue, Feb 6, 2024 at 7:01?AM Jules Ryckebusch < ryckebusch@...> wrote: I am using?Schottky Diodes? 40V ones?? I based this on a EDN article on for input protection.
?
Hey there Jules, thank you for the update. I have put together many of your boards since you started with the opa Alice, and I have just started with the smaller piezo SMD boards, very lovely devices.?
I may be showing the green behind my ears but may I ask which diodes you are using in this update?
Thank you for all you do in this community.? On Tue, Feb 6, 2024 at 5:45?AM Jules Ryckebusch < ryckebusch@...> wrote: I Just had a really cool adventure recording Humpbacks with my hydrophones. See this:?
One challenge was the failure of two of them post build.? I also had a couple board?failures after initial?testing of the boards?prior to attaching the Piezo cylinders. There were two modes of failure. Complete failure of the Opamp causing?a higher than normal current draw. Second, it still worked but with a lot of noise.? The light?bulb went off as I realised that I was directly connecting the cylinder to the Piezo element. I connected my Oscope to the cylinder and tapped on it. I could easily generate 15-20 volt spikes that were visible on the scope. Reviewing the literature, I realized I wasn't?including any input protection. Yes there are internal diodes for this in the opamp. I suspect they are fine for "normal use". I am updating the circuit as seen below: 
This includes a series resistor?and two diodes to shunt anything to ground and the supply pins. Conveniently there is a .1uF cap across the supply rails of the opamp that will act as a low Z source for this too.?
I have my first boards back from PCBWay and will commence testing shortly.?
Love any advice?or feedback here.?
-- Best Regards,
Jules Ryckebusch
214 399 0931
--
Best Regards,
Jules Ryckebusch
214 399 0931
|
Re: Input protection for OPA1642 for Piezo use. Oh, and Humpback Whales
I am using?Schottky Diodes? 40V ones?? I based this on a EDN article on for input protection.
?
Hey there Jules, thank you for the update. I have put together many of your boards since you started with the opa Alice, and I have just started with the smaller piezo SMD boards, very lovely devices.?
I may be showing the green behind my ears but may I ask which diodes you are using in this update?
Thank you for all you do in this community.? On Tue, Feb 6, 2024 at 5:45?AM Jules Ryckebusch < ryckebusch@...> wrote: I Just had a really cool adventure recording Humpbacks with my hydrophones. See this:?
One challenge was the failure of two of them post build.? I also had a couple board?failures after initial?testing of the boards?prior to attaching the Piezo cylinders. There were two modes of failure. Complete failure of the Opamp causing?a higher than normal current draw. Second, it still worked but with a lot of noise.? The light?bulb went off as I realised that I was directly connecting the cylinder to the Piezo element. I connected my Oscope to the cylinder and tapped on it. I could easily generate 15-20 volt spikes that were visible on the scope. Reviewing the literature, I realized I wasn't?including any input protection. Yes there are internal diodes for this in the opamp. I suspect they are fine for "normal use". I am updating the circuit as seen below: 
This includes a series resistor?and two diodes to shunt anything to ground and the supply pins. Conveniently there is a .1uF cap across the supply rails of the opamp that will act as a low Z source for this too.?
I have my first boards back from PCBWay and will commence testing shortly.?
Love any advice?or feedback here.?
-- Best Regards,
Jules Ryckebusch
214 399 0931
-- Best Regards,
Jules Ryckebusch
214 399 0931
|
Re: Input protection for OPA1642 for Piezo use. Oh, and Humpback Whales
Hey there Jules, thank you for the update. I have put together many of your boards since you started with the opa Alice, and I have just started with the smaller piezo SMD boards, very lovely devices.?
I may be showing the green behind my ears but may I ask which diodes you are using in this update?
Thank you for all you do in this community.?
On Tue, Feb 6, 2024 at 5:45?AM Jules Ryckebusch < ryckebusch@...> wrote: I Just had a really cool adventure recording Humpbacks with my hydrophones. See this:?
One challenge was the failure of two of them post build.? I also had a couple board?failures after initial?testing of the boards?prior to attaching the Piezo cylinders. There were two modes of failure. Complete failure of the Opamp causing?a higher than normal current draw. Second, it still worked but with a lot of noise.? The light?bulb went off as I realised that I was directly connecting the cylinder to the Piezo element. I connected my Oscope to the cylinder and tapped on it. I could easily generate 15-20 volt spikes that were visible on the scope. Reviewing the literature, I realized I wasn't?including any input protection. Yes there are internal diodes for this in the opamp. I suspect they are fine for "normal use". I am updating the circuit as seen below: 
This includes a series resistor?and two diodes to shunt anything to ground and the supply pins. Conveniently there is a .1uF cap across the supply rails of the opamp that will act as a low Z source for this too.?
I have my first boards back from PCBWay and will commence testing shortly.?
Love any advice?or feedback here.?
-- Best Regards,
Jules Ryckebusch
214 399 0931
|
Input protection for OPA1642 for Piezo use. Oh, and Humpback Whales
I Just had a really cool adventure recording Humpbacks with my hydrophones. See this:?
One challenge was the failure of two of them post build.? I also had a couple board?failures after initial?testing of the boards?prior to attaching the Piezo cylinders. There were two modes of failure. Complete failure of the Opamp causing?a higher than normal current draw. Second, it still worked but with a lot of noise.? The light?bulb went off as I realised that I was directly connecting the cylinder to the Piezo element. I connected my Oscope to the cylinder and tapped on it. I could easily generate 15-20 volt spikes that were visible on the scope. Reviewing the literature, I realized I wasn't?including any input protection. Yes there are internal diodes for this in the opamp. I suspect they are fine for "normal use". I am updating the circuit as seen below: 
This includes a series resistor?and two diodes to shunt anything to ground and the supply pins. Conveniently there is a .1uF cap across the supply rails of the opamp that will act as a low Z source for this too.?
I have my first boards back from PCBWay and will commence testing shortly.?
Love any advice?or feedback here.?
-- Best Regards,
Jules Ryckebusch
214 399 0931
|
Re: Reducing the sensitivity of electret capsules with built-in fet
I¡¯ll post some a link to the raw files and a reaper session later today ?? Best Regards,
Jules Ryckebusch?
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On Feb 4, 2024, at 10:39, Andrzej Sochon <andrzej.ams8@...> wrote:
? Jules, Very interesting recording! I have the impression that YouTube distorts the sound of the high tones of the hi-hats. Any possibility to listen the hi-rez audio of the?? Kind Regards, Andrzej Sochon On Thu, 11 Jan 2024 at 13:03, Jules Ryckebusch < ryckebusch@...> wrote: This is the challenge with built?in FET electrets. I have successfully?used the?TSB2555B with a 220pF capacitor across the capsule as a pad. THey make excellent drum mics. This works great for snares, toms and hi hats.?Overheads actually don't?need a pad. I am using my OPA circuit and the impedance buffer, which replaces the fet and associated circuitry. It is not as easy a solution as what you are looking for, but they sound great. See this for how it works:?
Jules
To be more specific, my goal is to have a microphone that is closer in sensitivity to "instrument" mics so I can use it at least as an overhead over drums. As it is now, it's pretty much unusable even with the PAD activated on the preamp. Simply the microphone output is too hot.
--
Best Regards,
Jules Ryckebusch
214 399 0931
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Re: Reducing the sensitivity of electret capsules with built-in fet
Jules, Very interesting recording! I have the impression that YouTube distorts the sound of the high tones of the hi-hats. Any possibility to listen the hi-rez audio of the?? Kind Regards, Andrzej Sochon
On Thu, 11 Jan 2024 at 13:03, Jules Ryckebusch < ryckebusch@...> wrote: This is the challenge with built?in FET electrets. I have successfully?used the?TSB2555B with a 220pF capacitor across the capsule as a pad. THey make excellent drum mics. This works great for snares, toms and hi hats.?Overheads actually don't?need a pad. I am using my OPA circuit and the impedance buffer, which replaces the fet and associated circuitry. It is not as easy a solution as what you are looking for, but they sound great. See this for how it works:?
Jules
To be more specific, my goal is to have a microphone that is closer in sensitivity to "instrument" mics so I can use it at least as an overhead over drums. As it is now, it's pretty much unusable even with the PAD activated on the preamp. Simply the microphone output is too hot.
--
Best Regards,
Jules Ryckebusch
214 399 0931
|
Re: Vintage Victor HM-200 binaural headphone - How to open?
Hi kennjava
Thank you for your answer and the story about your binaural experiments! I sometimes record from vinyl and listen to cassette tapes in the car quite often. I have some cassettes that friends recorded 30 years ago. They still work great! Unbelievable, magnetic tape! Despite the digital age, I still like it.
Today I received the parts I ordered. A few PUI 5024 electrets. 68K resistors, 3.3uF capacitors, Sn63Pb37 solder, mic cable and some connectors. Regarding the mic housing, I'm going to try to?build a hybrid SASS-Lite/HM-200-tube binaural bamboo mic housing prototype. Why make it easy? :) It won't be a headphone type and I'm sure I'll end up with a hum or noise.
?
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Re: Vintage Victor HM-200 binaural headphone - How to open?
Hi Heinz. Thanks for the follow-up, the pictures, and the link to the binaural review.
I didn't realize that the HM-200 incorporated a sort of pinnae or directional body shape. Interesting.
Yes, binaural techniques are not new. I've experimented off and on with binaural recording for over 30 years now (portable cassette, MiniDisc, and now digital field recorders). From the beginning, I made some binaural mic sets by taking a cheap set of small Walkman-style open headphones, removing the headphone drivers, and carefully installing small electret omni mics, wrapped in soft open-cell foam. I just solder the ends of the the existing headphone cables to the mics, and haven't had hum or noise issues. In use... I just wear them. Portable and stealthy :-) I will also place them around a tree trunk or similar. For the small cost, the results are often great. If you want to start experimenting with newer electret mics, this is a great starting point.
My favourite binaural experiment went like so: On a nice summer day, I put the "mic" headphones on, started recording and went for a walk in a park near us. As I walked, i periodically narrated where i was, the direction I faced, and other geographic references. Then, on a different day, i play the recording back, while walking the same route as cued by the narration. I'd hear something (eg a bike passing me) look in the apparent direction... there's nothing there. It was uncanny how real the playback image can be, when you hear it in the same place it was recorded.
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Re: Vintage Victor HM-200 binaural headphone - How to open?
Many thanks for your replies and your interest in this topic.?
Because of the discovery of Johan (I don't perceive the typical hole in the middle¡) I would like to follow up a little.
I think it's a better choice to listen to wise men and to leave the HM-200 alone for now. Instead, I will focus on building new microphones and take inspiration from vintage mic building designs. But I agree to kennjava also. To install new Primos or PUI electrets would be an interesting trial.
Regarding binaural recording I found an interesting article. Source: ResearchGate
(some pictures from the archives look really funny¡ lol :-)?
I thought binaural technology is a very modern technology, but that is obviously not the case.?The HM-200E binaural headphone-microphone combination and its inventors are mentioned in the article.
?
?
I've added a photo of the HM-200 so you can easily see how the capsules are positioned. It¡¯s at a right angle to the sound-reflecting surface of the indicated auricle.
@Johan
When I find one, I'll let you know. The following article about may be of interest to you.
@andrzej
Many thanks! I always try to find a place where there is no wind.?When I recorded the ducks, I may have been lucky that I didn't use microphones with a higher SNR. I'm sure that significantly more background noise would have been recorded.
Thank you and sorry for the late reply!
Heinz
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Re: Vintage Victor HM-200 binaural headphone - How to open?
Dear Heinz,
One more thing...Wind is a nightmare, more sensitive capsules means more wind sensitivity.? Wind-shields could help but may dump clearness. Good luck with your experiments.
I bought vintage binaural headphones from Victor last year. It's from 1976 and still works. If anyone is interested, I have placed the specs and a test recording in the Victor HM-200 folder. When I took the test recording, the headphone was quite heavy. The weight, including the batteries, is approx. 600 g. I looked strange but the ducks didn't care. :-)?
Does anyone know how to open the HM-200 headphones without breaking it? I haven't been able to find a way yet. I'm just curious about the capsule dimensions and what the circuitry looks like and whether more sensitive capsules would fit.
Many thanks!
Heinz
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Re: Vintage Victor HM-200 binaural headphone - How to open?
Thanks for the kind words Heinz. Your recordings and the info triggered my interest in (semi) binaural recordings again. I did experiments 15 years ago with some Aevox Audio mics - a brand I rand for a decade. Thanks for your proposition to keep me informed.
Best regards, Johan
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Re: Vintage Victor HM-200 binaural headphone - How to open?
Andrzej is wise, and if tho HM-200 still works properly, and? keeping it in?its original condition is important to you, then yeah, leave it alone....?
If they were mine, though, would open them up for sure. That's just how I roll. I own and have rebuilt or repaired several pairs of headphones. New.cables, new drivers... some are now Frankenheadphones made of bits from different brands and models.?
I bet that new Primo or PUI electrets would have better specs than the originals, so that's something that I would change. And I might rewire new mics to use PiP powering rather than the onboard AA? cells.
It should be possible to fabricate some effective wind-shields out of foam or fake fur.
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Re: Vintage Victor HM-200 binaural headphone - How to open?
On Tue, Jan 30, 2024 at 11:34 PM, Pierre Olivier wrote:
foam windsceens
Many thanks for the information. You're right. I'm missing the foam windshields. I'll try building new ones. The Victor HM-200 on eBay seems to be way overpriced. There's one on Yahoo Auction in Japan for $43, which seems like a fair price. However, without the original housing and without a dummy head.
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Re: Vintage Victor HM-200 binaural headphone - How to open?
It appears this device is also known as the JVC HM-200e. more info on this site:
I don't know if your specimen has the foam windsceens, that would explain the wind problems you had. I suppose you could easily fashion some yourself. There's a Victor HM-200 on sale on ebay now, for $480 us. I think those could be easily modified for PIP, permitting to eliminate the batteries and their weight.
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Le 2024-01-30 09:09, Heinz a ¨¦crit?: Many thanks for your opinions. I really appreciate your thoughts!
Last year I read a lot about the World Soundscape Project ( ) , Soundwalking and Barry Truax Handbook for Acoustic Ecology ( ). I¡¯m still fascinated by the fundus of valuable information the WSP team put together. And I truly respect the works of Barry Truax.
One day I saw the HM-200 binaural headphone hanging on a shelf at a reuse store. It looked so strange that I had to smile. What's this?! :-) At first I didn¡¯t realize that it was a binaural headphone. When I saw the three quarter inch inch jacks I became curious. Victor binaural headphone! I was able to test the functionality at the store and was happy about the find. Needless to say, it was a bargain. I did some test recordings and wanted to use it for soundwalking in the beginning, but it turned out that the mic capsules on the outer side of the ear cups are very susceptible to wind noise. In addition, the ear pads are made of leather. When you wear them, especially when it's not cold outside, your ears get really hot. It feels uncomfortable after a while. Although I enjoyed listening to what I recorded, using it in combination with a dummy head may be a better choice. When it wasn¡¯t windy or indoors, I was amazed about the spaciousness of the recordings. I usually take the HM-200 with me when I'm recording something interesting and trying out different types of microphones anyway. For example, when I recorded the Suikinkutsu sounds for my @NaturePattern YT channel.
@Johan
Many thanks for listening to the ducks recording and your finding. If you tell me which tests are of interest to you, I'll be happy to assist or send you some other recordings.
@kennjava
You are right! There is a tiny gap around the cup edge where the leather earpads are pressed into. At first I thought it was glued, but that's not the case. I haven't removed the ear pads yet.? When I open it, I upload some photos to the HM-200 folder.
@pete
Many thanks for pointing me to your tutorial. It helps a lot.
The HM-200 is equipped with a 1.5v AAA battery on each ear cup side. I connected it to the stereo mic input of a Sony PCM M10 using an adapter cable and disabled PiP on the Sony.
@andrzej
Thank you. I appreciate your advice! I'm always amazed when vintage things from 50 years ago still work great. I usually leave it as is. If I see room for improvement, I would like to try implementing it. But I agree, the original character of the vintage binaural headphones would be gone if it's not possible to put it back together as it was.
@Johan, Pete & Andrzej
If you want me to pay attention to a HM-200, I wouldn't mind dropping you a note and sending it to you if I stumble across another one.
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Dude
Andrzej Sochon