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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.
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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 On 1/19/25 16:53, Scott Helmke wrote:
I was doing PF5102 to replace the on5087, but those are also EOL. --
---- Scott Helmke ---- scott@... ---- (734) 604-9340 ---- "I have ceased distinguishing between the religious and the secular, for everything is holy" - Joe Henry |
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Re: SMD transistors for Alice/Schoeps
I was doing PF5102 to replace the on5087, but those are also EOL.
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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, --
---- Scott Helmke ---- scott@... ---- (734) 604-9340 ---- "I have ceased distinguishing between the religious and the secular, for everything is holy" - Joe Henry |
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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Sadly that one is obsolete with through hole ones still available.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.
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Best Regards, Jules Ryckebusch On Jan 19, 2025, at 16:43, jack via groups.io <jackreynolds100@...> wrote: |
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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 |
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Re: short pickup range options
Could one of the following capsules that PUI released last year be a good starting point to DIY something?
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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.
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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.
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Anyone interested to DIY something with similar performance?
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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
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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
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This might be a more permanent link: |
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Re: short pickup range options
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This one? |
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Re: short pickup range options
The definitive close range mike is the .
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This is a cardioid (IIRC) with a highly sloped response that is compensated by Proximity.? The exact proximity is set by the bar that is supposed to be placed on the user's top lip.
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The highly sloped response kills the LF ambient noise and the very close distance set by the bar does most of the rest.
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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. |
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Re: short pickup range options
Some time ago I had a conversation with someone who was making a video about sewing, and wanted to include the actual audio of the sound of needles passing through cloth!
They had been advised that using a low noise, high quality, highly directional shotgun mic? was the way to go.... They had been advised to look at the Sennheiser range!
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I pointed out that the inverse square law (already described in this thread) made the proximity of the mic to the source the most important factor in determining how successful they were likely to be in getting a useful result - especially when recording such tiny signals.? ?
That of course doesn't automatically mean using an expensive mic!.... I suggested using a Primo EM172 -? located only a few cm. from the source? - might work, and made a short video clip to illustrate the point ...
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If it is an option to locate a small mic slose to the source, then I would suggest that's likely to produce the best 'selective' audio recording results.
Even a highly directional, very low noise mic will? - at a longer distance - almost certainly produce inferior results.??
As Jerry has already commented - you can't 'twist the laws of physics' !
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Re: short pickup range options
Due to the reverse square law, a useful signal will distinguish itself better from the background when going close to the source. That's the main thing. Radio people sometimes opt for dynamic mics. Due to the higher mass of the membrane and the resulting inertia, distant, weaker sounds, don't come through so well. It's a case of trial and error, and I wouldn't hope for a high-quality result. Coles lip microphone (ribbon) makes use of the proximity effect to reduce far-away noises, especially the lower frequencies. Sensitivity is misleading here. Op ma 13 jan 2025 om 19:21 schreef cx b via <clistburnham=[email protected]>:
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Johan Vandermaelen 6 Moon Parrizal sonic scenography Hofveldweg 47, 9420 Aaigem Belgium +32(0)473 343 880 |
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Re: short pickup range options
Yes but that¡¯s kind of different than having a physical distance limitation. I think most applications to accomplish what you may be trying to achieve use filters and gates.? Like dynamic vocal mics on a stage use high pass filtering and sometimes a noise gate or another type of threshold to determine when to allow signal through, especially in loud reverberant spaces with loud heavy drums.? On Mon, Jan 13, 2025 at 10:21?AM cx b via <clistburnham=[email protected]> wrote:
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Re: short pickup range options
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Le 13/01/2025 ¨¤ 19:21, cx b via
groups.io a ¨¦crit?:
Yes, and so what? The sensitivity of a microphone can be altered by changing the preamp gain. Whatever the sensitivity/gain combination, the ratio between distant and close sounds doesn't change. You'd be wrong. Piezo microphones were quite popular in the 50's and 60's. they didn't require contact between the capsule and the person who talked.
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Re: short pickup range options
certainly there are "less sensitive" microphones, though, right? i suppose the most obvious example would be something like a piezo, where there would actually need to be direct contact with the element in order to produce a voltage. On Sun, Jan 12, 2025 at 5:52?AM Jerry Lee Marcel via <jerryleemarcel=[email protected]> wrote:
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Re: Active noise cancelling for microphones in noisy environments - techniques?
Do you know the mic level you need for the Garmin GNC255? Turning your pot mostly towards to zero means, that you are using a low level close to the 70mV you specified? ?
Sorry, I meant I turned the pot mostly towards zero resistance.
I've not measured the output amplitude properly during typical use with the foam on, but I'd shot for about 300mV peak-to-peak at zero pot resistance on the oscilloscope to close proximity normal speech when it was in pieces on my bench. The Garmin GNC255 requires 70mV - 1000mV depending on what its mic input gain has been set to. ?
There's plenty of scope to increase the amplitude on my mic setup. The second op-amp stage is just a buffer so could easily be given gain via a feedback resistor.
For reference, the Bose A20 mic outputs 600mV at 114dB SPL. ?
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Re: Active noise cancelling for microphones in noisy environments - techniques?
Regarding this Figure-8 mic, it has an undamped membrane, meaning the frequency response has a +6dB/decade slope. The datasheet is a bit misleading, showing a "Typical Omnidirectional Frequency Response", i.e. with the back port covered. With the back port uncovered, it has this slope, which can be seen in Figure 16 of
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The application note proposes compensating with an electronic filter.
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Re: Freshwater Soundscapes...
You can order PCBs from PCBWay - link in Jules' instructable - and order the components locally.
It's easy to build.
Be advised - the default quantity in the order form is 5 pieces. But 10 pieces cost the same money :)
Also pay attentionbto shipping method - there are less expensive ones (though slower) than the default.
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You can also order populated PCB but it costs substantially more. You'd need to compare prices.
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The difficult part is cylindrical piezo element. These are expensive and hard to get.
But it is the best option. Top tier :) You can also use more common piezo elements. |
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