isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Mon Aug 05, 2013 4:20 am Post subject:
Arp 4072 self osc few problems. Subject description: please help. |
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Hi Yves and Guys.
first, i want to ask if its normal to see the meters on my spectrum analizer running up and down when turning the Freq pot while nothing is connected to the input and all other pots are down?
second, i have bleedthrough, not the one that one need to replace the 50k pot to a dual one, another one, i can hear the VCO when all the pots are down, very low but still there.
third, when nothing is connected to the input and all the pots are all the way down and my amp is on all the way up (full volume) when turning up the Freq pot a bit there is this "ELECTRIC PACK/CLICK" at the start/opening of the filter that almost killed my monitors.
i test the V from the freq pot with my DVM and it seems ok, its going up in a linear way, when freq pot all the way down I get 0V.
i actually think that all of the first 2 problems is because the last problem.
i think that if we fix the third problem the first 2 will be history.
i'll be more then grateful for your help.
EDIT:
I must add that I replace the TL074 to another brand cause the last brand probably was a fake, made a lot of noise at the output.
I also tried lm342, lf444, TL084, still the same.
cheers,
Isak E. _________________ http://www.myspace.com/mgmtrance |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Thu Aug 08, 2013 4:24 am Post subject:
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ok, i run some tests.
I've checked the V at the output when nothing connected to the input and all the CV pots are all the way down, the reso and the cutoff are all the way down as well.
i get 6.20V at the output, when starting to turn the freq pot slowly i get 1.2V.
its the same measurement all the freq scale up, 1.2V.
should i get V at the output if nothing is connected to the input and all the pots are down? _________________ http://www.myspace.com/mgmtrance |
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