It is good to be reminded that the thermal noise of the air pressure on the diaphragm limits the noise at mid-high frequencies and the RF techniques are lower noise mainly at the low end because they don't need the G-Ohm bias resistor. There is a trade off in terms of reliabiliy and JFET leakage that makes a commercial designer think twice about simply dropping in a 50G Ohm resistor.
If we speak about condenser microphone, there is an optimal diaphragm size, as a compromise between noise level and upper frequency response. Neuman microphones were successful because they found this optimum for frequency response that was standard then. No need for 50G resistors, and even 0.5G resistors are shunted well by about 100 pF of the capsule capacitance.
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Please give us an example!
Probably he means less interference from light dimmers with IGBT than from light dimmers with FETS?
Still a few dB of room for improvment at those numbers, but yes at 1" it works. They still had to work hard to get the frequency response.
Santa,
I want a 1/4" B&K microphone for Xmas for testing your speakers for the North Pole. And you can include the power supply that goes with it. I don't care how old it is as long as it works. Would help me with my beryllium dome tweeter development, my Earthworks mike won't go that high.
ps. I have tried to be a good boy this year and keep out of trouble. Thanks for bringing down the price of neodymium magnets this year.
I want a 1/4" B&K microphone for Xmas for testing your speakers for the North Pole. And you can include the power supply that goes with it. I don't care how old it is as long as it works. Would help me with my beryllium dome tweeter development, my Earthworks mike won't go that high.
ps. I have tried to be a good boy this year and keep out of trouble. Thanks for bringing down the price of neodymium magnets this year.
I've scheduled a trip to Scott Wurcer (if you don't mind Scott) as soon as I have some working prototype of an optical microphone array. The capsules (both omni and cardioid) were shipped today, "one pocket of them" (sic!)
I hope the pocket did not have remains of some cashews or other garbage.
Let's measure and tune them in the "Golden Lab"!
I hope the pocket did not have remains of some cashews or other garbage.
Let's measure and tune them in the "Golden Lab"!
Dimitri,
I once saw a complete set of 1/4", 1/2" and 3/4" capsules and all the cables and preamp in an original set on Ebay. Should have bought it at the time. Thank you for the offer, that is more than generous. I would feel bad having someone Else's prized possessions. I do have the Earthworks preamplifier and wonder if that would work with the B&K mike?
I once saw a complete set of 1/4", 1/2" and 3/4" capsules and all the cables and preamp in an original set on Ebay. Should have bought it at the time. Thank you for the offer, that is more than generous. I would feel bad having someone Else's prized possessions. I do have the Earthworks preamplifier and wonder if that would work with the B&K mike?
I made quite nice sounding thingies from their capsules with flanges around using a single R-C in feedback for EQ. Quite smooth up to 16 KHz.
I mean with a electrostatic input cap high impedance when polarized with high DC , witch need FET or tube, VS low impedance when hf polarization with BJT.Probably he means less interference from light dimmers with IGBT than from light dimmers with FETS?
What is so funny ?
You said "best IGBTs have a lower noise factor than FETs." Insulated gate bipolar transistors versus JFETs? I'm not aware of IGBTs used for much other than high power switching and amplification.
I've scheduled a trip to Scott Wurcer (if you don't mind Scott) as soon as I have some working prototype of an optical microphone array. The capsules (both omni and cardioid) were shipped today, "one pocket of them" (sic!)
I hope the pocket did not have remains of some cashews or other garbage.
Let's measure and tune them in the "Golden Lab"!
If it's optical we are interested, seriously. If you are interested we better take it to PM.
Brad explained. Please forgive our ignorance. I myself once was impressed when tried medium power Soviet KT626 transistors for low noise inputs in mic preamps, may be your finding is something similar, but we are unaware of it.
Sorry, i wrote IGBT instead of BJT, as i said, i'm not friend with acronyms. It was just a typo.
I have seen a copy of Ron's paper. It makes sense now, a nice academic overview of everything that's been done. Tables of results make sense op-amps with <1.5 V/us slewrate are not good for audio. There are several tables of amplifiers that didn't register, I'm happy enough with that . Read the results on Nelson's Zen amps, and then we can talk. Ball's in your court.
. Read the results on Nelson's Zen amps, and then we can talk. Ball's in your court.- Status
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