Umm.... 10pF, maybe? I actually haven't done this myself. A good film capacitor at 10pF will be both cheap and tiny, and that's the way many commercial mics...
thanks for straightening up my rough and ready drawing. but what transformer are you using? (except in situations of extreme electrical noise, i prefer the...
It's a Lundahl transformer, LL1659. http://www.lundahl.se/pdfs/datash/1659.pdf Actually I use LL1659 with center pin. I will update the schematic next week....
I'm thinking of building a high-quality stereo preamp based on INA217 or INA103. I need to get a dual-sided (+-) supply out of a single 6-9VDC battery. The...
Hi! I have some doubts on the connection of the zener diode used in the phantom circuit . I am using TSB140. The first circuit that I constructed was...
Oswaldo, The zener diode does seem to be backwards, but that is correct. A zener diode is like a regular diode which "breaks down" at high voltage, but a ...
... That's what I'm thinking about too, at the moment. I gathered some datasheets that I'll post some time later today, but I didn't try that voltage...
Larry, Rumors of my demise have preceded the actual fact. To quote Little Bill Daggett: "Hell, even I thought I was dead 'til I found out it was just that I...
The wire is probably covered with lacquer or similar coating. Try using a flame to burn it off before testing and soldering. It's probably not shielded, which...
... was in ... I have ... my email ... exact moment ... favorite ... can't send ... to you. ... Hi Eric, Glad to hear you haven't fallen off the edge. Sorry...
... Looking at the datasheets I gathered, I had to realize that those parts may not please you, on one hand, my project is lower voltage than yours, I plan to...
Hi! I have uploaded some files in my folder (Nikro). In the folder UEC-14AT you can find a microphone based on Scott Helmke's design with the UEC-14AT capsule....
... Hey, I think I've got a couple of those - I bought them while working in Norway last year. I'm not sure I've even tried hooking them up yet, though. ...
hi.
i'm building an "alice matched pair", i just select transistors with the same hfe measuring it with a cheap tester...
i'm using bf256 (fet for the...
The resistor isn't strictly necessary - it just makes it quicker for the circuit to settle at the desired bias point. Maybe your noisy mic's FET needed a...
thank you scott.
in my electronic shop said me that bf256 is equal to 2n4416...i don't know if the bias is the same...i'm not so good in elctronic theory......
I have a need to know. Please email pointers (as in the msg # here of suggestions for doing this or a procedure that is well thought that does not equate to...
PC, Just a quick response to tide you over until I have a chance to write a longer one. The principle method for testing microphones is the substitution...
Thank you Eric for your response. Quite helpful actually. I have a reference mic, so that is not an issue. The issue is I have yet to do the step below with...
I know what smaartPro is, but I haven't personally used it. So I don't know how easy it is to get the data out. So I'll describe the process using something...
Wow, what a great resource you and this group already are to me. Thank you Eric! phil... "The goal is to live with godlike composure, on the full rush of...
If I understand, you first tried to change the FETs, capsules & 1G resistor but there was no difference. Then you removed the 1G resistor and the noise went...
Well, I've never found a noisy 1gOhm resistor, but then I haven't actually looked for one. The noisy mics I've built have generally been fixed by replacing...
i tried to change the 1 giga resistor with another one that sounded good on another alice...
...no difference..so the problem is not the 1 giga res. i think....
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