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robboten
Joined: Nov 26, 2009 Posts: 36 Location: stockholm, sweden
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Posted: Sun Dec 16, 2012 6:14 am Post subject:
S&H negative V out |
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Having a strange problem with my S&H part of the noise/S&H pcb. The noise part works great, the random gate and the gate from S&H works (the led blinks and I get about 10V gate, which seems a bit high). But the S&H out clicks a bit and gives -10VDC out. I have changed the trans, the caps and the ICs, but no change. Anyone have clue how I could proceed? |
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iopop3
Joined: May 28, 2010 Posts: 94 Location: Malmö, Sweden
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Posted: Mon Dec 17, 2012 12:52 am Post subject:
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Make sure you're not feeding it a too hot signal. I think mine behaved the same, had to limit the peak to peak voltage on the noise in order to make it work properly.
I think the S&H only handles 6-8Vpp? I could be wrong, search this sub forum and you should find the posts discussing it.
EDIT: See this thread, http://electro-music.com/forum/topic-47352.html |
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robboten
Joined: Nov 26, 2009 Posts: 36 Location: stockholm, sweden
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Posted: Mon Dec 17, 2012 9:12 am Post subject:
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Thx for your reply. Unfortunatly I have tried lowering the resistor value and by then the voltage peaks for the noise. It makes no difference... It also makes no difference if I use another noise module or VCO as input or any other signal/gate/LFO as the other input. |
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robboten
Joined: Nov 26, 2009 Posts: 36 Location: stockholm, sweden
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Posted: Fri Dec 21, 2012 2:22 am Post subject:
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how is the values around c4 to supposed to be like? I have around 0-10.45VDC in and about 0-0.014 VDC on the other side... Seems strange to me.
Edit: Now I think that it's because my multimeter is to slow to pick up the fast pulse. Guess the problem is the C5 cap and that it doesn't hold. Will try some others.
What is the function of the D3 diode? When I emulate the circuit this one messes up the whole thing, when I remove it all works... |
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robboten
Joined: Nov 26, 2009 Posts: 36 Location: stockholm, sweden
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Posted: Sun Dec 23, 2012 3:44 am Post subject:
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Sticking to my monologue here...
My simulator had the wrong pic for N-fet/P-fet so thats why the diode messed up.
My working hypothesis now is that the source has a negative voltage to begin with so the jfet is constantly open. I will do further research. |
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robboten
Joined: Nov 26, 2009 Posts: 36 Location: stockholm, sweden
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Posted: Mon Feb 25, 2013 3:19 am Post subject:
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Ehm... I just wanted to tell you that I had misunderstood the function of the S&H module. I thought it would generate sound, not modulate an VCO for example. So all well now! |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Mon Feb 25, 2013 9:40 am Post subject:
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Ah, a learning process documented :-) _________________ Jan
also .. could someone please turn down the thermostat a bit.
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