OPA1678

Dual CMOS-Input Op-Amp DIP-8 / SOIC-8.6 circuits use this part. Listed as: Dual op-amp, DIP8; WSON-8.

Datasheet · from ti.com

Substitutes same socket

Parts that fit the same socket: the same function, pin count and pinout. The figures are read off each part's datasheet (this one's from page 8), 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	Input	Supply	GBW	Slew	Noise	Iq	Boards
OPA1678	RR out	4.5–36 V	16 MHz	9 V/µs	4.5 nV	2 mA	6

Surface-mount only (SOIC-8 and smaller), so a DIP socket needs an adapter; standard dual pinout.

Fits the same socket

Part	Input	Supply	GBW	Slew	Noise	Iq	Boards	Differs
LM833	bipolar	10–36 V	16 MHz	7 V/µs	4.5 nV	2.05 mA	144	rated from 10 V. Low-noise audio dual; needs at least ±5 V (10 V) and draws about 2 mA per amplifier.
UPC4570	bipolar	8–32 V	15 MHz	7 V/µs		2.5 mA	5	Low-noise, wideband audio dual; needs at least ±4 V (8 V) supply.
M5216		4–32 V	10 MHz	3 V/µs		2.25 mA	4	High-current dual (±100 mA load) meant for headphone drivers.
4580	bipolar	4–36 V	15 MHz	5 V/µs		3 mA	103	Low-noise, high-output-current audio dual from ±2 V; the DIP8 (NJM4580D) is listed as discontinued.
M5218		4–32 V	7 MHz	3 V/µs		1.5 mA	21	Low-noise audio dual the maker calls close to the 4558 and 4559, with ±50 mA load current.
NE5532	bipolar	10–30 V	12 MHz	5 V/µs	5 nV	3 mA	155	rated from 10 V. Low noise and strong output drive, but draws about 3 mA per amplifier and has 200 nA bias current.
NJM2100	bipolar	2–7 V	12 MHz	4 V/µs		1.75 mA	1	7 V max, not for 18 V. Low-voltage dual op-amp rated to ±3.5 V (7 V total), so it cannot run straight from 9 V.
NJM4565D	bipolar	8–36 V	10 MHz	4 V/µs		2.25 mA	2	Drives 20 V peak-to-peak into 400 Ω; the DIP8 (NJM4565D) is listed as discontinued.
TLE2072		4.5–38 V	10.6 MHz	32 V/µs	17 nV	2.4 mA	1	Fast, low-bias dual drawing about 2.4 mA per amplifier.
CA3260	mosfet, RR out	4–16 V	4 MHz	10 V/µs		4.5 mA	8	16 V max, not for 18 V; input range reaches the negative rail. CMOS output swings to both rails, but the 16 V supply limit rules out 18 V pedals.

Circuit	Based on	Category	Vendor	Box	Knobs	Price	BOM
Electro Harmonix Ripped Speaker Fuzz Vero20×21 Verified 2N3904 · 2N5088 · OPA1678 Electro-Harmonix Ripped Speaker Fuzz	Electro-Harmonix Ripped Speaker Fuzz	Fuzz	Dirtbox Layouts	—	4	—	34
ATtiny13A Buffered Electrical Bypass Quasi-IC 2N7002 · AP7375-50SA-7 · ATTINY13A-SSUR · OPA1678 Matt Garman ATtiny13A Buffered Electrical Bypass Quasi-IC	Matt Garman ATtiny13A Buffered Electrical Bypass Quasi-IC	Utility	Matt Garman	—	—	—	44
ATtiny202 Buffered Electrical Bypass Quasi-IC 2N7002 · AP7375-50SA-7 · ATTINY202-SS · OPA1678 Matt Garman ATtiny202 Buffered Electrical Bypass Quasi-IC	Matt Garman ATtiny202 Buffered Electrical Bypass Quasi-IC	Utility	Matt Garman	—	—	—	43
Median Compressor 2N5457 · OP1678 · OPA1678 Wampler Ego 76 · 125B	Wampler Ego 76	Compressor	PedalPCB	125B	6	$12.00	73
Paper Scratcher Fuzz 2N3904 · 2N5088 · OPA1678 Electro-Harmonix Ripped Speaker Fuzz · 125B	Electro-Harmonix Ripped Speaker Fuzz	Fuzz	PedalPCB	125B	4	$10.00	56
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