Build your own Delay as a DIY eurorack kit: https://www.ericasynths.lv/shop/diy-kits-1/edu-diy-bbd/
LABOR in the Erica Synths Webshop: https://www.ericasynths.lv/shop/diy-kits-1/edu-diy-labor/
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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