Parts · Opto

NSL32-R3

Optocoupler (LED + LDR).1 circuit uses this part.

Datasheet · archived copy from Silonex; the part is discontinued and the maker no longer publishes it

Substitutes same kind

Optocouplers and photoresistors of the same construction; the response speed and resistance range set how an effect sounds. The figures are read off each part's datasheet (this one's from page 1), typical where the sheet gives a typical value, otherwise the maximum. Closest first; the last column says what differs. A different part can change the sound, and a circuit may lean on one particular figure, so read the build document's notes before you swap.

This part

Part	On	Dark	Rise	Decay	Boards
NSL-32	500 @ 20 mA	500k	3.5 ms	500 ms	11

Slow decay (up to 500 ms to 100 kΩ), which suits optical compressors and tremolos.

Alternatives

Part	On	Dark	Rise	Decay	Boards	Differs
VTL5C9	1.5k @ 0.5 mA	2M	4 ms	50 ms	3	higher on resistance; higher dark resistance; faster decay. Fast-decay vactrol (about 50 ms to 100k) suited to tremolo; this is the Xvive 5C9 sheet.
VTL5C2	10k @ 0.5 mA	2M	3.5 ms	500 ms	13	higher on resistance; higher dark resistance. Xvive's 5C2-R equivalent; decay to 100 kΩ takes up to 500 ms.
VTL5C6	6k @ 5 mA	400k	3.5 ms	50 ms	1	higher on resistance; faster decay. Xvive 5C6 equivalent: 40 to 80 kΩ at 0.5 mA, 6 kΩ max at 5 mA, decay to 1 MΩ in about 50 ms.
VTL5C4	1.2k @ 1 mA	400M	6 ms	1500 ms	2	higher on resistance; higher dark resistance; slower decay. Very low on-resistance (125 Ω at 10 mA) but a slow decay of up to 1.5 s.
VTL5C3	30k @ 1 mA	10M	2.5 ms	35 ms	21	higher on resistance; higher dark resistance; faster decay. Low light memory and temperature drift; the sheet prints its 10 mA and 40 mA on-resistance as 5 Ω and 1.5 Ω, almost certainly meaning kΩ.

Faceplate	Circuit	Based on	Category	Vendor	Box	Knobs	Price	BOM
	VFE MiniMu LM358 · NSL32-R3 · OPA134 · TLE2074 Optical AutoWah	Optical AutoWah	Wah / Envelope	Madbean	—	3	—	52