Designing a simple analog delay from scratch (BBD)

Build your own Delay as a DIY eurorack kit: LABOR in the Erica Synths Webshop: Support the channel... ... through Patreon: ... by buying my other DIY kits: Simulation in CircuitJS (discrete component BBD): Join my Discord community: Here’s an interesting problem: how do you create a delayed duplicate of a sound without recording it to some sort of storage medium? Back in the days before digital signal processing and cheap, abundant memory, this was a prime engineering issue. Until two Engineers named Sangster and Teer came up with a deceptively simple solution: the bucket brigade delay. In this video, I attempt to reverse engineer the architecture of a classic BBD, recreate a bare bones version on the breadboard – and then use a proper BBD chip to design a simple DIY audio delay. If you want to build along, here’s the bill of materials: BILL OF MATERIALS RESISTORS 2M2 x1 100k x8 82k x1 56k x1 51k x1 47k x1 39k x1 22k x3 10k x2 6k2 x1 4k7 x1 CAPACITORS 1 uF x2 10 nF x1 1 nF x1 (more if you want to build the discrete component BBD!) 220 pF x2 TRANSISTORS & DIODES 1N4148 (small signal diode) x5 J113 (N-CH JFET) x1 (more if you want to build the discrete component BBD!) POTENTIOMETERS 100k (A104) x1 100k (B104) x3 10k (B103) x1 CHIPS TL072 (dual op amp) x3 V3205SD/MN3205 (BBD 4096) x1 4046BE (PLL) x1 SWITCHES SPDT (Single pole, double throw) x1 Chapters 00:00 BBD Overview 01:43 Analog Sampling 10:09 Sample Transfer 16:28 Buffering & Listening 19:50 Dual Tap Reconstruction 23:01 More Stages with the V3205 27:55 Reconstruction Sampling 33:26 Dry/Wet Mixing 34:41 Feedback 36:04 Flanger Mode 41:43 Inhibit CV 42:59 Sound Demo & Outro