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2kohm
Joined: Feb 19, 2013 Posts: 52 Location: germany
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Osal
Joined: Aug 16, 2011 Posts: 147 Location: Here
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Posted: Thu Apr 04, 2013 4:15 am Post subject:
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To make the video of the breadboard it is a very nice the idea!
May I ask why you didn't connect the op-amp's non inverting input to ground? _________________ electronic-sea.net |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
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2kohm
Joined: Feb 19, 2013 Posts: 52 Location: germany
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Posted: Thu Apr 04, 2013 10:47 am Post subject:
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Thank you guys
one blemishes but it makes no audible difference.
yes! i used the UA741 veteran tested also with lm324 tl072 tl07X.
I think every singel opamp works!
15 v not tested but i think it works also
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_________________ Shop
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Stromakustik.de |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
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2kohm
Joined: Feb 19, 2013 Posts: 52 Location: germany
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Posted: Thu Apr 04, 2013 12:00 pm Post subject:
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thanks
i try to convert it in a pink noise and some random noise modes. _________________ Shop
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Stromakustik.de |
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Cynosure
Site Admin
Joined: Dec 11, 2010 Posts: 966 Location: Toronto, Ontario - Canada
Audio files: 82
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Posted: Thu Apr 04, 2013 3:23 pm Post subject:
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Nice! Thanks for posting the response charts. _________________ JacobWatters.com |
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beesontoast
Joined: Feb 03, 2014 Posts: 7 Location: SW UK
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Posted: Mon Feb 03, 2014 9:33 am Post subject:
Darn it, I can't make it work! |
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I can make most things work, given time, but this - despite its elegant simplicity - has me stumped.
I have used all-new parts, tested them all (the 741 by substitution) and double-checked connections. I have tried it on a speaker, a 386 op-amp, a small but very sensitive amp I use for other projects, and earphones and I get nothing, nada.
If there was one component I should try varying a value for, which would you suggest? |
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2kohm
Joined: Feb 19, 2013 Posts: 52 Location: germany
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beesontoast
Joined: Feb 03, 2014 Posts: 7 Location: SW UK
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Posted: Tue Feb 04, 2014 4:16 am Post subject:
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Thanks - I will play some more.
One thing though - you have + (pin 3 on a 741) on the op-amp going to ground on that diagram...
Your drawing of a PP3 also shows reversed polarity... Last edited by beesontoast on Tue Feb 04, 2014 5:00 am; edited 1 time in total |
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2kohm
Joined: Feb 19, 2013 Posts: 52 Location: germany
Audio files: 4
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beesontoast
Joined: Feb 03, 2014 Posts: 7 Location: SW UK
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Posted: Tue Feb 04, 2014 5:19 am Post subject:
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I can make some pretty weird noises by coupling it to a 386 op-amp and ignoring pin 3 as per the original circuit - something like a cow with bellyache attacking a duck...
But nothing remotely like white noise.
Oh - I also made a pretty fair EMF detector by putting a coil and a 100nf in series between pins 2 and 3. |
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2kohm
Joined: Feb 19, 2013 Posts: 52 Location: germany
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beesontoast
Joined: Feb 03, 2014 Posts: 7 Location: SW UK
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Posted: Tue Feb 04, 2014 6:19 am Post subject:
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I tried a PN2222, BC517 and currently BC547B. |
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beesontoast
Joined: Feb 03, 2014 Posts: 7 Location: SW UK
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Posted: Thu Feb 06, 2014 1:06 pm Post subject:
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I have solved the problem I had with the first circuit by adding in a potentiometer, and it turns out with a resistance of about 240 ohms I get white noise in a single 16 ohm earpiece.
(added) It turns out that a small electrolytic in that position also does the job. |
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2kohm
Joined: Feb 19, 2013 Posts: 52 Location: germany
Audio files: 4
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beesontoast
Joined: Feb 03, 2014 Posts: 7 Location: SW UK
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Posted: Thu Apr 10, 2014 8:45 am Post subject:
White noise generator using LM386 Subject description: circuit diagram |
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Here's my LM386 version:
It will oscillate at lower voltages, but seems to require a full 12v to produce white noise.
https://www.dropbox.com/s/luvp9vtbp5nup5y/2014-05-02%2009.10.26.jpg Last edited by beesontoast on Fri May 02, 2014 1:17 am; edited 1 time in total |
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555
Joined: Feb 06, 2010 Posts: 10 Location: Chile
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Posted: Thu May 01, 2014 5:49 pm Post subject:
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beesontoast wrote: | I have solved the problem I had with the first circuit by adding in a potentiometer, and it turns out with a resistance of about 240 ohms I get white noise in a single 16 ohm earpiece.
(added) It turns out that a small electrolytic in that position also does the job. |
Hi
Where exactly did you connect the potenciometer? i have the same problem than you, i almost tried everything, but i can't fix the problem (i spend hours try to realize what is wrong )
thanks! |
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beesontoast
Joined: Feb 03, 2014 Posts: 7 Location: SW UK
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Posted: Fri May 02, 2014 1:19 am Post subject:
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555 wrote: |
Where exactly did you connect the potenciometer? i have the same problem than you, i almost tried everything, but i can't fix the problem (i spend hours try to realize what is wrong )
thanks! |
In place of the 1M resistor. It does seem to be important to use a 12v supply - 9v does not work. |
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555
Joined: Feb 06, 2010 Posts: 10 Location: Chile
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Posted: Fri May 02, 2014 8:01 am Post subject:
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beesontoast wrote: | 555 wrote: |
Where exactly did you connect the potenciometer? i have the same problem than you, i almost tried everything, but i can't fix the problem (i spend hours try to realize what is wrong )
thanks! |
In place of the 1M resistor. It does seem to be important to use a 12v supply - 9v does not work. |
Thanks!
i was suspecting that does't work with a 9v battery, anyway i will try the potenciometer, thanks |
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narges_1992
Joined: Sep 11, 2014 Posts: 1 Location: iran
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Posted: Thu Sep 11, 2014 3:19 am Post subject:
Subject description: hi can you tell me about the ampilifier of this circuit , i have problem to produce this sound |
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Taller de Teknologia Libr
Joined: Jul 11, 2018 Posts: 4 Location: Chile
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Posted: Thu Sep 29, 2022 10:38 am Post subject:
white noise into opamp amplifier |
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hi everybody , ive managed to build this white noise generator , and ive tried to pass it through an amplifier build out of opmaps as well . but when inputing to the opamp i get nothing , im building a device for my sister , cause my niece wont fall asleep if she doesnt listens to white noise ( LOL) do yo have any input on whats going wrong ive read that opamps cant amplify a white noise but havent figured out why . thanks for the great info. will apreciate some help.
pd: im triying to build a standalone 1 watt speaker circuit amplifier circuit and input the white noise |
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gabbagabi
Joined: Nov 29, 2008 Posts: 651 Location: Berlin by n8
Audio files: 23
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Posted: Thu Sep 29, 2022 12:34 pm Post subject:
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hi taller
there are two schematics here,
one is using a dual power supply, which seems to work
the second seems to have problems, i guess because of the missing virtual ground
which oneyou are using?
which kind of power source do you use? |
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