Re: Idea for variable pattern microphone
OPA1644 is the quad version of the 1641 (single) and 1642 (dual) The advantage of having only two power pins for 4 opamps is often negated by the more difficult layout.
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Jerry Lee Marcel
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#33906
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Re: Idea for variable pattern microphone
With an OPA 1644?
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Mic Scharf
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#33905
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Re: Hex inverter issue. Alice OPA
What are you using for Capules? SimpleP48 is for Electret ones that have a built in FET. Best Regards, Jules Ryckebusch
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Jules Ryckebusch
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#33904
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Re: Hex inverter issue. Alice OPA
Jerry, I have measured 32mV. Jules, It does work, but 90% of signal is white noise alone. There are no 50Hz components visible to me in EQ, so that tells me everything should be grounded properly.
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LonDek
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#33903
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Re: Switchable patterns in Dual OPA Alice with dual capsule
#°Õ¸é±«·¡°ä°¿±·¶Ù·¡±·³§·¡¸é¡±²Ñ±õ°ä¸é°¿±Ê±á°¿±··¡³§
#dualopaalice
Sure post more details! I think a new PCB wouldn't be a problem, just need the correct schematic.
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Mic Scharf
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#33902
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Re: Idea for variable pattern microphone
That would do it. Got a lead on one that is 20-20K and inexpensive? I just used my last batch of good ones on a 12 channel mic splitter. They were pico brand and $67 each. Best Regards, Jules
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Jules Ryckebusch
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#33901
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Re: Idea for variable pattern microphone
Why don't you stick a transformer in there and be done with it?
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Pierre Olivier
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#33900
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Re: Idea for variable pattern microphone
I'll look at it further. This was my first attempt. :-) -- Best Regards, Jules Ryckebusch 214 399 0931 Linkedin <https://www.linkedin.com/in/jules-ryckebusch/>
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Jules Ryckebusch
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#33899
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Re: Idea for variable pattern microphone
That's pretty damn clever! I'm quite fond of my fully balanced outputs though, but I know we're pretty much limited to two x OPA1642s (providing 4 op-amps) with phantom power. Is there a way of making
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michaeljtbrooks@...
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#33898
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Idea for variable pattern microphone
You guys all have me thinking here. As I was falling asleep last night I thought of this. See attached. In essence we take the both diaphragms and go to a High Z buffer. Then the rear goes to a unity
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Jules Ryckebusch
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#33897
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Re: Hex inverter issue. Alice OPA
Wiktor, let me ask again here, does it work when used in a microphone? I am suspecting it will. Jules wrote:
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Jules Ryckebusch
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#33896
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Re: Hex inverter issue. Alice OPA
If you connect a 1G resistor in series with the multimeter, it forms a voltage divider by 1/1000, so every mV you me??? asure is an acual volt at the circuit's output. You should measure 80mV.
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Jerry Lee Marcel
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#33895
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Re: Hex inverter issue. Alice OPA
Yea Jerry, you are correct here! the 1gig isn't a path for current flow. OOpppsss... Jules wrote:
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Jules Ryckebusch
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#33894
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Re: Hex inverter issue. Alice OPA
I've connected 1 gigaohm resistor in series with multimeter, and then measured milivolts. Everything is still invalid, voltages are same as without 1gohm resistor. niedz., 10 kwi 2022 o 06:25 Jerry
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LonDek
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#33893
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Re: Switchable patterns in Dual OPA Alice with dual capsule
#°Õ¸é±«·¡°ä°¿±·¶Ù·¡±·³§·¡¸é¡±²Ñ±õ°ä¸é°¿±Ê±á°¿±··¡³§
#dualopaalice
Further to that comment, I took a look at Jules' dual OPA schematic here; https://content.instructables.com/ORIG/FTV/ESBC/KKV5OYHS/FTVESBCKKV5OYHS.pdf I think it should be possible to achieve what
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Arjay1949
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#33892
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Edited
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Re: Hex inverter issue. Alice OPA
Actually, once the capacitor is charged, there is no more current drawn, except the fraction of femtoAmpere due to residual resistance of the insulating materials, which is way higher than gigaohms.
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Jerry Lee Marcel
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#33891
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Re: Source of dynamic capsules?
I asked a similar question a while back and got some great resources. Here's the link to that discussion. /g/MicBuilders/message/32497 I did end up getting a few takstar capsules, a
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Princeton of the Universe
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#33890
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Re: Hex inverter issue. Alice OPA
Hello, I've read that ealier! Tho I completely did not understand what was going on in this article, now I know. Damn I think my mental breakdown just hit another level, trying different IC's,
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LonDek
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#33889
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Re: Hex inverter issue. Alice OPA
https://audioimprov.com/AudioImprov/Mics/Entries/2016/7/4_Bias_Voltage_for_True_Condenser_Capsules.html This explains what you're seeing and how to measure with a cheap 1M meter.
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Henry Spragens
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#33888
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Re: Hex inverter issue. Alice OPA
That would actually cause what you are seeing. Big question: Does it work when providing bias voltage to the capsule? Remember those are literally a 50-100pF capacitor that we are charging up to
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Jules Ryckebusch
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#33887
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