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synthetic
Joined: Jun 02, 2007 Posts: 76 Location: Glendale, CA
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Posted: Sun Nov 30, 2008 9:51 pm Post subject:
S&H Clicking |
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I just finished the Sample and hold/noise module from Bridechamber. I have the default noise going to the S&H circuit. When I turn the slew all the way down, there's a substantial click with every clock pulse. Is this normal? |
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synthetic
Joined: Jun 02, 2007 Posts: 76 Location: Glendale, CA
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Mon Dec 01, 2008 5:48 am Post subject:
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I suppose that it is the direct sound from VCOs (no filter, no VCA, no EG).
Which PCB are you using ?
I guess that this click depends a bit on the characteristics of Q5, try different BF245 to find one less "clicking". Another thing you may do is to play with the value of C4 (try smaller values down to 1nF) _________________ Yves |
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synthetic
Joined: Jun 02, 2007 Posts: 76 Location: Glendale, CA
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Posted: Mon Dec 01, 2008 11:43 am Post subject:
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That audio file is a pair of MOTM 300 oscillators (one FM modulated by the Random out of the board) into a MOTM 490 Moog filter. The filter is FM modulated by the S&H. I'm using a MOTM 190 VCA as an attenuator only.
I purchased the board as part of the full kit from Bridechamber. He shipped me a pair of TL074s instead of a TL074 and a LM324, could this be the problem? |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Mon Dec 01, 2008 12:44 pm Post subject:
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No TL074 are OK _________________ Yves |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Tue Dec 02, 2008 12:51 am Post subject:
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synthetic wrote: | That audio file is a pair of MOTM 300 oscillators (one FM modulated by the Random out of the board) into a MOTM 490 Moog filter. The filter is FM modulated by the S&H. |
OK are you sure that the click you hear is not some kind of CV bleedthrough of your MOTM 490. To check this you can modulate the MOTM490 with a LFO in squarewave mode with a 10Vpp amplitude. In such a case can you hear a clicking ?
Have you got a scope ? _________________ Yves |
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synthetic
Joined: Jun 02, 2007 Posts: 76 Location: Glendale, CA
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Posted: Tue Dec 02, 2008 9:29 am Post subject:
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yusson wrote: | OK are you sure that the click you hear is not some kind of CV bleedthrough of your MOTM 490. To check this you can modulate the MOTM490 with a LFO in squarewave mode with a 10Vpp amplitude. In such a case can you hear a clicking ?
Have you got a scope ? |
No clicking when I modulate the 490 with a square wave. No, I don't have a scope. |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Tue Dec 02, 2008 9:59 am Post subject:
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So it rules out CV bleedthrough. No you may try and change the value of C4.
Another thing you could do is to add a 100 ohm resistor in series with the slew rate pot. _________________ Yves |
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