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NULL-A Build & BOM Null-A is an all-in-one analogue synth packed into 42HP. It features: 2 VCOs 3 VCAs Sequencer 1 state variable VCF 2 LFOs Clock Divider 1 ladder VCF Mixer Sample & Hold (S&H) 1 VC Delay...
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Most of these are simply to save a few patch-cables. The interesting one is the signals from the Sequencer, Sloth chaos and Tri from LFO2 are mixed and fed to the S&H sample input. This means it is continually generating stepped and smooth CVs (for there is a Slew pot) that are different but related to everything else that is going on.
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PART VALUE COMMENTS NUMBER 100p 100p 220nF 100n 100n 100n 100n 470p 100n 100n not on vers 2 100n 100n 100n 100k 100n 100k or thru-hole 220R 100k 100k 100k 100k 100k 100k 100k 100k...
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R247 100k Trimpot 1k SOT23-6 AKA R248 100k SOT-457 R249 Q13, Mouser Part No: R250 BCM847 771-BCM847DS115 R251 SOT23 Q1, Q3, There is no Q25 R252 Q5, Q7, on vers 2. R253 R254 Q10, R255 Q14, R256 100k Q15, Q16, R257 100k Q18,...
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COMPONENT QUANTITY COMMENTS 2 pin bipolar LED 100k pot 1MA pot MONO jacks Kobiconn type STEREO jack Kobiconn type Eurocrack power connector single vactrol anything okay, even DIY 10 Pin 2.54mm Single Row Tayda: A-1306 Female Pin Header 40 Pin 2.54mm Single Row at least 4 cut into 10 pin lengths Pin Header Strip...
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Set-Up VCOs: The 100k trimpots on the VCOs are used to set up the panel pots so they have minimal dead zones at the start and ends of their travel. The 20k trimpots are used to dial in 1V/oct tuning; you should be able to get 3 octaves of decent tracking from these VCOs.