On Tue, Apr 8, 2025 at 04:55 AM, Jules Ryckebusch wrote:
Look at this one:?? One of my reasons for choosing the OPA1642 was idle current. The OPA1633 ?has >10ma which for a phono preamp with external supply is not an issue?
Best Regards,
?
Jules Ryckebusch
?
OPA1633 is a bipolar differential amp with an Optimum Source Impedance of about 800 ohms. hardly suitable for a MM preamp.
You must have confused it with another.
OPA1655/56 are JFET with 2.9nV/sqrtHz IN density.
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ADA4625-2 bifet
from Analog Devices is 3.3nV/rootHz at 1kHz, and 5.5nV/rootHz at 10Hz. Current noise 4.5fA/rootHz at 1kHz
The OPA828 JFET has 4nV/rootHz at 1kHz, 7.5nV/rootHz at 10Hz, and 1.2fA/rootHz current noise. Available as a dual OPA2828. Surface mount of course.
And the only bipolar opamp to beat the NE5534 is the OPA210. 2.2nV/rootHz at 1kHz, an amazing 2.5nV/rootHz at 10Hz, and crucially for MM cartridges current noise of 400fA/rootHz (same as for the NE5534). It is just better in all respects than the Neanderthal NE5534.? And available as a dual OPA2210.
If you put it into my RIAA amp spreadsheet, for typical cartridge R and L the OPA210 only finds you 0.6dB improvement in SNR as compared to the NE5534. For a factor of 5 times greater cost. But distortion is vanishingly low, it only draws 2.5mA quiescent, and inevitably is only surface mount. And cheerfully drives 600 ohms with no degradation in distortion.
Craig
------ Original Message ------
Date 08/04/2025 03:55:22
Subject Re: [MicBuilders] FET OPAs for mikes
Look at this one:?? One of my reasons for choosing the OPA1642 was idle current. The OPA1633 ?has >10ma which for a phono preamp with external supply is not an issue?
Best Regards,
Jules Ryckebusch? On Apr 7, 2025, at 21:32, Richard Lee via groups.io <ricardo_lee@...> wrote:
? It's actually for a Jurassic application with of no modern importance;? RIAA MM preamps in DIYaudio.? I'm surprised that NE5534 is still one of the best for this; slightly beaten only by $$$ OP627 or Unobtainium NJM2068.
?
In theory, a FET OPA with <3.5nV/rtHz & low 1/f, popcorn noise bla bla should trounce 5534
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Look at this one:?? One of my reasons for choosing the OPA1642 was idle current. The OPA1633 ?has >10ma which for a phono preamp with external supply is not an issue? Best Regards,
Jules Ryckebusch?
toggle quoted message
Show quoted text
On Apr 7, 2025, at 21:32, Richard Lee via groups.io <ricardo_lee@...> wrote:
? It's actually for a Jurassic application with of no modern importance;? RIAA MM preamps in DIYaudio.? I'm surprised that NE5534 is still one of the best for this; slightly beaten only by $$$ OP627 or Unobtainium NJM2068.
?
In theory, a FET OPA with <3.5nV/rtHz & low 1/f, popcorn noise bla bla should trounce 5534
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It's actually for a Jurassic application with of no modern importance;? RIAA MM preamps in DIYaudio.? I'm surprised that NE5534 is still one of the best for this; slightly beaten only by $$$ OP627 or Unobtainium NJM2068.
?
In theory, a FET OPA with <3.5nV/rtHz & low 1/f, popcorn noise bla bla should trounce 5534
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I am using the OPA1642. It is 5.1nV√Hz. The OPA1652 is 4.5?nV√Hz? Both are very good. What is your noise floor based on out of curiosity?
Jules
I'm a bit out of touch with modern OPAs but note there are a number of new DIY mikes using FET OPAs like Homero's Charis and the OPA Alice.
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I'm after a FET OPA with less than 3.5nV/rtHz noise @ 1kHz and good 1/f, popcorn noise bla bla.
?
What do you guys use and recommend ??
-- Best Regards,
Jules Ryckebusch
214 399 0931
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I'm a bit out of touch with modern OPAs but note there are a number of new DIY mikes using FET OPAs like Homero's Charis and the OPA Alice.
?
I'm after a FET OPA with less than 3.5nV/rtHz noise @ 1kHz and good 1/f, popcorn noise bla bla.
?
What do you guys use and recommend ??
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Re: New Mic builder - First Post!
Welcome and thanks for the nice introduction to yourself and your projects! You already gained quite some experience in a short time. There's a lot of information available on DIY mic building on the internet, here and elsewhere on the internet. Enough inspiration for years of mic building!
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Jan
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Re: New Mic builder - First Post!
Welcome to the club! Best Regards,
Jules Ryckebusch?
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Show quoted text
On Apr 4, 2025, at 14:20, Mic mauler via groups.io <ljelley1@...> wrote:
?
Hey guys (and gals),
I just wanted to drop a line to say thanks to this community. This is my first post, but I have been reading the board for the past few weeks.
?
I am a singer (amateur with mediocre talent) and am interested in recording some stuff at home. Most of my mics are dynamic and I have really wanted to get a decent condenser, but just cannot bring myself to spend the hundreds of dollars to buy a "good" mic. I have owned an MXLV67 for over a decade but have never been happy with the sound so it has spent most of it's life in it's box. A few weeks ago, I ran across a YouTube video of someone building a condenser mic and the bug bit me.
?
After a bit of research on the internet, I found JLI and watched the build videos. I ordered the parts for a "Samantha" OPA Alice board with the 34mm electret capsule. I also got mounting kit, 34mm saddle, and 22nF caps for the XLR as instructed in the video.? I bought the cheapest CAD 1800 ($17) mic on Amazon just to get a donor body and after a couple days of tinkering, managed to build my first microphone. The first time I plugged it in was truly magical. For a little under $100 I have a great sounding mic with very little noise. I sang for several hours straight just enjoying it and playing with different compression, EQ, and effects settings. Despite my poor soldering skills, it turned out great!
?
So of course, down the rabbit hole I go. My next project was to build with a true condenser capsule and following the JLI videos again, I ordered an OPA Alice board, the hex inverter board, the K47 capsule and installed them in a cheap U87 body I bought for $23 on walmart.com. It was on this project that I made my first major mistake. I overheated one of the xlr pins and bent it out of place, so I ordered some XLR inserts from amazon. Meanwhile, I finished installing the pcbs and capsule and waited for parts. As soon as the parts came in, I finished the mic and it worked the first time! My soldering is getting better now and I am more confident with it. This mic sounds great, but still has a bit of noise that I intend to chase down. Probably poor soldering hygiene.?
?
While waiting for parts I came across this https://www.opic.jp137.com/index-multi.html webpage and started contemplating assembling a pcb from scratch. This led me to Mic Scharf’s PCBway shared projects (https://www.pcbway.com/project/member/?bmbno=8A368813-05C9-44). So I ordered the MP PCB, hex inverter pcb, and the opa alice handheld boards (5 of each). I had a lot of fear of the soldering required so I worked on a couple of practice soldering projects while waiting for the parts to come from China.
?
In the meantime, I ordered parts from Mouser enough to complete 2 of the OPA Alice handheld microphones and 2 of the 25mm electret capsules from JLI. Last night I completed my first pcb and installed it in a KMS 105 clone I bought off amazon for $10. It worked the first time I plugged it in and it sounds amazing. This might be my favorite microphone yet. I need to see if it can stand being plugged into my PA system for a little karaoke with out it feeding back. I am skeptical cause it is ultra hot with very little gain on my Yamaha interface.
<3mics.jpg> <IMG_0269.jpg> <IMG_0268.jpg> <IMG_0267.jpg> <IMG_0260.jpg> <IMG_0257.jpg> <IMG_0256.jpg>
So I started my journey back on 3/14/2025 with my first order to JLI. Here I sit three weeks later with 3 completed microphones and parts for another on hand. I spend way too much time surfing Chinese websites for cheap mic parts and am working on a Mouser order for my next project. Can we form a 12 step support group or something, cause clearly I have a problem.
Thanks again to Jules and all the others on this site who inspire ordinary folks like me to leverage this technology. Whole new worlds are opening up to me when I see what can be built from PCBway projects as well. I have a lot of interest outside of microphones like retro computing and I want to build some stuff for my commodore 64 now.
|
New Mic builder - First Post!
Hey guys (and gals),
I just wanted to drop a line to say thanks to this community. This is my first post, but I have been reading the board for the past few weeks.
?
I am a singer (amateur with mediocre talent) and am interested in recording some stuff at home. Most of my mics are dynamic and I have really wanted to get a decent condenser, but just cannot bring myself to spend the hundreds of dollars to buy a "good" mic. I have owned an MXLV67 for over a decade but have never been happy with the sound so it has spent most of it's life in it's box. A few weeks ago, I ran across a YouTube video of someone building a condenser mic and the bug bit me.
?
After a bit of research on the internet, I found JLI and watched the build videos. I ordered the parts for a "Samantha" OPA Alice board with the 34mm electret capsule. I also got mounting kit, 34mm saddle, and 22nF caps for the XLR as instructed in the video.? I bought the cheapest CAD 1800 ($17) mic on Amazon just to get a donor body and after a couple days of tinkering, managed to build my first microphone. The first time I plugged it in was truly magical. For a little under $100 I have a great sounding mic with very little noise. I sang for several hours straight just enjoying it and playing with different compression, EQ, and effects settings. Despite my poor soldering skills, it turned out great!
?
So of course, down the rabbit hole I go. My next project was to build with a true condenser capsule and following the JLI videos again, I ordered an OPA Alice board, the hex inverter board, the K47 capsule and installed them in a cheap U87 body I bought for $23 on walmart.com. It was on this project that I made my first major mistake. I overheated one of the xlr pins and bent it out of place, so I ordered some XLR inserts from amazon. Meanwhile, I finished installing the pcbs and capsule and waited for parts. As soon as the parts came in, I finished the mic and it worked the first time! My soldering is getting better now and I am more confident with it. This mic sounds great, but still has a bit of noise that I intend to chase down. Probably poor soldering hygiene.?
?
While waiting for parts I came across this https://www.opic.jp137.com/index-multi.html webpage and started contemplating assembling a pcb from scratch. This led me to Mic Scharf’s PCBway shared projects (https://www.pcbway.com/project/member/?bmbno=8A368813-05C9-44). So I ordered the MP PCB, hex inverter pcb, and the opa alice handheld boards (5 of each). I had a lot of fear of the soldering required so I worked on a couple of practice soldering projects while waiting for the parts to come from China.
?
In the meantime, I ordered parts from Mouser enough to complete 2 of the OPA Alice handheld microphones and 2 of the 25mm electret capsules from JLI. Last night I completed my first pcb and installed it in a KMS 105 clone I bought off amazon for $10. It worked the first time I plugged it in and it sounds amazing. This might be my favorite microphone yet. I need to see if it can stand being plugged into my PA system for a little karaoke with out it feeding back. I am skeptical cause it is ultra hot with very little gain on my Yamaha interface.
      
So I started my journey back on 3/14/2025 with my first order to JLI. Here I sit three weeks later with 3 completed microphones and parts for another on hand. I spend way too much time surfing Chinese websites for cheap mic parts and am working on a Mouser order for my next project. Can we form a 12 step support group or something, cause clearly I have a problem.
Thanks again to Jules and all the others on this site who inspire ordinary folks like me to leverage this technology. Whole new worlds are opening up to me when I see what can be built from PCBway projects as well. I have a lot of interest outside of microphones like retro computing and I want to build some stuff for my commodore 64 now.
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Of course, Aliexpress is not an official Primo dealer, and everything is bought with caution and the best of hopes.
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Thank you very much! The order will be completed, I will try it, I will tell you if it is interesting
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Re: Dismantling LDC to use capsules as ORTF in a blimp
Thanks for all the replies
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@Jules- thanks for the paper, interesting reading, and thanks for confirming about LDC ORTF
?
I will probably forego dismantling the smaller mics, and use them more traditionally, I was getting a little ahead of myself, I have several pairs of micbooster clippys I can use in SASS or Olson half-sphere rigs.?
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I know there are some shortcomings in using LDC for ORTF but I figure it's worth a go
?
cheers
?
Damian
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Re: Dismantling LDC to use capsules as ORTF in a blimp
MEant to include this in my email. ORTF does rely on the pattern of the microphone. With that?being said being able to change that in post really makes this technique shine.
ways of s?
On Sat, Mar 22, 2025 at 12:06 PM, Roger Gustavsson via Still, the as hoff-axis response of large diameeuter capsules will show up in an ORTF setup. Den l?r 22 mars 2025 kl 17:15 skrev Jules Ryckebusch w2h0 w2h0via w2h0via as zvia <rychoOo 9 936-661-6969kebusch= gmail.com@groups.io>: ORTF works great with LDC’s infinite all the time. Especially with pattern adjustable dual output mics.? Best Regards,
Jules Ryckebusch? ? ORTF is intended for small diaphragm?capsules. With large diaphragm?capsules the result may be a bit different.
Depends how you choose to mount the boards. If there are no components on the other side and you mount them on the same surface as the capsules - say on the lid - it seems these wires should be long enough. But it depends also on stand offs you choose. You will determine it when putting it all together. There's no way to know beforehand. And from the photo alone ?
-- Best Regards,
Jules Ryckebusch
214 399 0931
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The mic connector for these Sennheiser packs is a LEMO, about $35 and needs a specific crimp tool.? There is a 3rd party connector that's not crimped (but still very tiny to work with) called the RED16 from Redding Audio.? Also about $35.
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The manual for the SENNHEISER 5212 transmitter is here:
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The manual contains the pinout of the mic connector. A preamp is not necessary.
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Be careful; I don't believe that AliExpress are authorized dealers for Primo, so what you're seeing might be a copy.
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Re: Dismantling LDC to use capsules as ORTF in a blimp
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Show quoted text
On Sat, Mar 22, 2025 at 12:06 PM, Roger Gustavsson via groups.io <roger.krokavadet@...> wrote: chu b Still, the as hoff-axis response of large diameeuter capsules will show up in an ORTF setup. Den l?r 22 mars 2025 kl 17:15 skrev Jules Ryckebusch w2h0 w2h0via w2h0via as zvia <rychoOo 9 936-661-6969kebusch= gmail.com@groups.io>: ORTF works great with LDC’s infinite all the time. Especially with pattern adjustable dual output mics.? Best Regards,
Jules Ryckebusch? ? ORTF is intended for small diaphragm?capsules. With large diaphragm?capsules the result may be a bit different.
Depends how you choose to mount the boards. If there are no components on the other side and you mount them on the same surface as the capsules - say on the lid - it seems these wires should be long enough. But it depends also on stand offs you choose. You will determine it when putting it all together. There's no way to know beforehand. And from the photo alone ?
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Re: Dismantling LDC to use capsules as ORTF in a blimp
Still, the off-axis response of large diameter capsules will show up in an ORTF setup.
ORTF works great with LDC’s infinite all the time. Especially with pattern adjustable dual output mics.? Best Regards,
Jules Ryckebusch? ? ORTF is intended for small diaphragm?capsules. With large diaphragm?capsules the result may be a bit different.
Depends how you choose to mount the boards. If there are no components on the other side and you mount them on the same surface as the capsules - say on the lid - it seems these wires should be long enough. But it depends also on stand offs you choose. You will determine it when putting it all together. There's no way to know beforehand. And from the photo alone ?
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Re: Dismantling LDC to use capsules as ORTF in a blimp
Le 22/03/2025 à 14:34, damiandrohanphoto via groups.io a écrit?:
1. Is it possible to use cardioid capsules in a SASS type array? I know the pickup pattern would be different. My plan would be to have the mics dismantled as with the example above. Has anyone tried it?
When you flush-mount cardioid capsules, they are no more cardioid, they are more or less omni. But the tuning of cardioid and omni is different. The response may lack LF. You might like it, or not.
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Re: Dismantling LDC to use capsules as ORTF in a blimp
ORTF works great with LDC’s infinite all the time. Especially with pattern adjustable dual output mics.? Best Regards,
Jules Ryckebusch?
toggle quoted message
Show quoted text
On Mar 22, 2025, at 11:11, Roger Gustavsson via groups.io <roger.krokavadet@...> wrote:
? ORTF is intended for small diaphragm?capsules. With large diaphragm?capsules the result may be a bit different.
Depends how you choose to mount the boards. If there are no components on the other side and you mount them on the same surface as the capsules - say on the lid - it seems these wires should be long enough. But it depends also on stand offs you choose. You will determine it when putting it all together. There's no way to know beforehand. And from the photo alone ?
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Re: Dismantling LDC to use capsules as ORTF in a blimp
ORTF is intended for small diaphragm?capsules. With large diaphragm?capsules the result may be a bit different.
Depends how you choose to mount the boards. If there are no components on the other side and you mount them on the same surface as the capsules - say on the lid - it seems these wires should be long enough. But it depends also on stand offs you choose. You will determine it when putting it all together. There's no way to know beforehand. And from the photo alone ?
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Mic mauler
John Thaden
Roger Gustavsson