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I have a question regarding the EMI/RF suppression caps. On this page:??the value is .22nF (220pF) and here 22nF. That is a big difference, what is right?.

Thank you Mic Scharf!

I will work on reading through the info!

Best Regards,
Jesse

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Sadly, the 2555 data sheet you link to is mostly nonsense.? This capsule is a FETless electret, and the data sheet has details of the characteristics of the impedance converter shown in the schematic -- which doesn't exist within this capsule??
(The 2555 capsule only contains the part shown within the dotted line box on the schematic)
So, although you don't need a polarising voltage - as recordinghacks has already indicated - you will need an impedance converter.? That can be a Schoeps style FET interface, or perhaps an op amp impedance converter?
Mic Scharf has already linked to my Mid/side project . The FETless version of that project? shows how you might interface a capsule like the 2555, in it simplest form.
And it will be the capsule noise itself which dominates with that circuit.

I bought several?
TSB2555 capsules and looking at the datasheet it says the operating voltage is 1-10V?
( ). Seems like a?
big range...any recommendations of what voltage to get the lowest self noise and highest?
SPL? Lowest noise matters most to me. Also can the TSB2555 be used in a Schoeps style circuit?

That capsule is an electret. It needs no polarizing voltage.

Regarding “lowest self noise,” you might end up considering a larger capsule. Capsule self-noise is inversely proportional to active diaphragm area. Said another way, larger capsules have (or at least potentially have) lower noise than smaller capsules.

Another factor is capsule sensitivity. The higher the capsule’s output level, the lower noise the microphone could have — because you’ll need less preamp gain to get a usable signal level into the DAW. Preamps add noise (especially consumer-grade preamps, especially at high gain settings), but even at low gain they’re amplifying both the signal and the noise from the mic. The higher the signal level from the mic, the less preamp gain you’d need, which tends to result in a lower-noise track.

I’m not sure I understand the need for low noise AND high SPL. I think that microphones built for high SPL can afford to be noisier, and in fact typically are noisier, because the mic’s noise floor will be inaudible as compared to the very loud signal. In the case of condenser mics, the circuit can easily overload due to a high SPL transient — or, the downstream preamp could clip if the mic’s output voltage is too high. There are several common solutions to that, such as putting a capacitive pad on the mic’s input circuit, and/or attenuating the signal within the circuit to reduce the likelihood that the preamp clips. But most of those solutions effectively lower the signal-to-noise ratio of the mic. In other words: raising SPL capability also raises the mic’s effective noise floor. You’ve turned down the signal, but the mic’s native noise floor stayed the same (hence: lower signal-to-noise ratio), and you need more preamp gain to hear the attenuated signal, so the preamp amplifies the mic’s noise floor.

Audio design usually involves tradeoffs.?

The TSB2555 can be used in a Schoeps style circuit, although the full Schoeps circuit includes a DC multiplier that electret capsules do not need. The DC circuit in a Schoeps mic contains roughly 50% of the components of the circuit, so that’s not a trivial thing. You wouldn’t want to build a Schoeps circuit from a schematic if you’re using the TSB-2555, because you’d be doing twice as much work as needed.

Other people on this forum can point to PCBs for Schoeps-based *audio* circuits that more easily adapt to the TSB-2555. Or you could see buy MicParts S-25, which is a full mic kit with a Schoeps-derived audio circuit. (Full disclosure: I developed and sell that kit, so the previous sentence is an advertisement, not an impartial recommendation.)

But, as suggested above, if your goal is lowest possible noise, the TSB-2555 won’t get you there. By way of comparison, the MicParts S-87 (a large-diaphragm mic kit with a full Schoeps circuit and a very high-output capsule) delivers 6-8dB higher output than typical electret Schoeps mics, with lower noise.?

Also, if you want highest possible SPL, the Schoeps circuit wouldn’t be my first choice.

—
matt.

Hello!

Back in the mic making game and working on a Mid-Side setup! Anyways, I bought several TSB2555 capsules and looking at the datasheet it says the operating voltage is 1-10V (). Seems like a big range...any recommendations of what voltage to get the lowest self noise and highest SPL? Lowest noise matters most to me. Also can the TSB2555 be used in a Schoeps style circuit? I assume so but would like to verify.?

Thanks!

Best regards,
Blair

Hi everyone, I am new to this forum. I found it after reading a lot of info about building a microphone. What I would like to know is where to get parts and a donor mic shell in order to build a custom mic. Here are something things I am hoping for. Lowest cost as possible but even it it cost a lot more I am fine as long as its the quality I want. A fairly neutral sounding mic. Not over hyped or harsh highs. A solid bottom and lowest self noise as possible. I really hoping to buld a mic that is 7dba or lower on self noise but I know this may be rough doing it myself. 10dba would be ok. I want very lush lows and smooth highs that don't have sharp explosive Sss.?

Here is my background. I have modded a couple studio projects b3 mics. One I put a k12 capsule in and the other a k47. Then I ended up selling them for some dumb reason thinking I wasn't going to need them. Bad idea. I did not modifiy the circuit at all. With the k47 capsule the highs were not harsh and the mids/highs sounded very smooth. However I did not care for the lows as I felt like it did not have much body. The k12 capsule had wonderful lows. It was beautiful but the highs sounded great and not harsh, instead had very sharp Sss. It was a very narrow band Sss sound and even a de esser did not make it sound good. Over all the mic had 14dba of self noise.?

I can solder. Not the best but its not a problem.?

I am willing to buy a pre made circuit board. This would be the best, but if its less expensive I can buy parts and solder the pieces. I just need to know where to by the parts from.?

I did see the microphone parts website however, I feel that is a little out of my price range. I am sure they are very great builds. I am hoping to make something cheaper.?

Very low self noise is very important. I can find a bunch of mics that have much higher self noise, but I want ultra quiet.?

Thanks again for your time and thought.

Best Regards,
Jesse

FYI I learned about the SnapEDA library and the Digikey library for Kicad last year and it cleans up alot of that troublesome transitional period you're talking about (switching platforms). It would be worth a peek to get those libraries and Kicad and try them out together.?

-L.

Thanks for the suggestions.??The DesignWorks schematic / simulation software?I have been using?is no longer supported on Macs. The Douglas CAD/CAM system is still around, but upgrading to the current full version is $400. The advantage is my libraries could be carried over. The disadvantage is price for an occasional simple hobby project.?I am not laying out 6-layer impedance controlled motherboards these days.

I'll check out KiCad and Eagle, but the more I think about wrangling new libraries into shape and learning a new UI, the more attractive keeping the old Cube on a desk looks. :-)

开云体育

I had been using pcb-rnd on linux, but got tired of having to remember lots of linuxy stuff to maintain it.

I recently started using librePCB on mac, it is likely more limited than kicad, but I had taken a dislike to kicad for some reason I don't now recall.

I am building up a library of my own thru-hole components for mics using librePCB

I think librePCB has decent potential but it is still new. The overall paradigm feels closer to a mac program than other pcb layout software I have tried.

I can't say enough kind things about Kicad 6. It's seriously competitive and I say this as a user and owner of Diptrace with a pro license.? If only there was a more universal format for collaboration between platforms.?

Footprint creation and symbol editing are actually pretty straight forward though you still need your calculator from time to time for PCB layouts.?

-L.