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gdavis
Joined: Feb 27, 2013 Posts: 359 Location: San Diego
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Posted: Sat Jun 22, 2013 3:51 pm Post subject:
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Now that I think about, I think the P10x thing only affects the automatic voltage measurements which you're not using, but not the waveform on the screen. The cal thing is important for reading voltage of waveform off the screen accurately though.
I don't really have anything else to offer except that almost all my problems with boards I've etched have been the result of accidental solder bridges or gaps in traces (which can be very small and hard to see with the naked eye). I tracked them down by testing continuity with my multimeter on anything that didn't look perfect. A magnifying lamp or microscope is a great thing to have too. _________________ My synth build blog: http://gndsynth.blogspot.com/ |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Sat Jun 22, 2013 11:34 pm Post subject:
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thanks man, youve been very helpful
i took some pics outdoors this morning, hope they are better.
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_________________ http://www.myspace.com/mgmtrance |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Sun Jun 23, 2013 1:16 am Post subject:
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Well I checked the board and it looks all good.
So as you asked, it might be a problem either due to a defective LM3900 or a bad matching of the BC557 pairs. _________________ Yves |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Sun Jun 23, 2013 1:24 am Post subject:
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thanks Yves.
to tell you the truth, as long as it sound how it suppose to sound i really dont care how the self osc looks or sound at above 14khz.
i dont reach those freqs when playing.
i'll upload few sound clips later on today, hope you will have the time to listen to them.
thank you for your help Yves.
much appreciated. _________________ 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: Sun Jun 30, 2013 1:16 am Post subject:
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sorry it took me long time to upload the audio clips.
but hey i made them
the first is saw wave on C2.
reso all the down, reso at 1/4, reso at 1/2, reso at 3/4 and reso on full.
the second is square on C2.
reso all the down, reso at 1/4, reso at 1/2, reso at 3/4 and reso on full.
only VCO and the Arp VCF, are involve, no VCA.
so, are they good?
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_________________ http://www.myspace.com/mgmtrance |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Sun Jun 30, 2013 1:43 am Post subject:
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Looks mostly correct. For the auto-oscillation there is a problem of aliasing with the recording. Otherwise it sounds saturated at high frequencies. _________________ Yves |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Sun Jun 30, 2013 1:47 am Post subject:
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so only the self osc if a bit problematic cause of the high gain?
is this correct? _________________ http://www.myspace.com/mgmtrance |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Sun Jun 30, 2013 1:59 am Post subject:
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Probably if you set the resonance at the beginning of auto-oscillation it will sound more as expected. _________________ Yves |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Sun Jun 30, 2013 11:53 pm Post subject:
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ok, i found the problem after tracing the audio path.
it was a "bad" TL074!
i tell you... those Chinese ebay sellers
now its not buzzy any more. _________________ 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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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Sun Jul 07, 2013 12:24 am Post subject:
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Thanks for the info _________________ Yves |
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