UA308

1 circuit uses this part.

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 3), 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
LM308	bipolar	10–36 V				0.3 mA	96

Needs a compensation capacitor (30 pF typical) between pins 1 and 8; the cap sets slew rate and tone.

Fits the same socket

Part	Input	Supply	GBW	Slew	Noise	Iq	Boards	Differs
LM301A	bipolar	10–36 V		1 V/µs		1.8 mA	23	draws 1.8 mA per amplifier. Externally compensated: needs a capacitor (30 pF for unity gain) between pins 1 and 8, and the value sets its slew and treble response in fuzz and distortion circuits.
OP07CP	bipolar	6–36 V	0.6 MHz	0.3 V/µs	9.8 nV		1	internally compensated: the board's capacitor across pins 1 and 8 no longer shapes the tone; pins 1, 5, 8 are offset null (1, 8), NC (5). Precision but slow (0.3 V/µs); its offset trim uses pins 1 and 8, not the 741's 1 and 5.
TS321	bipolar	3–30 V	0.8 MHz	0.4 V/µs	50 nV	0.6 mA	1	internally compensated: the board's capacitor across pins 1 and 8 no longer shapes the tone; pins 1, 5, 8 are NC; input range reaches the negative rail. Single-supply LM321-style op-amp sold only in SOIC-8 and SOT-23, so a DIP socket needs an adapter.
NE5534	bipolar	10–30 V	10 MHz	13 V/µs	4 nV	4 mA	44	needs a compensation capacitor across pins 5 and 8; draws 4 mA per amplifier. Compensated for a gain of 3 or more; below that it needs a capacitor (22 pF) between pins 5 and 8.
CA3130	mosfet, RR out	5–16 V	4 MHz	10 V/µs		10 mA	54	MOSFET input; 16 V max, not for 18 V; input range reaches the negative rail; rail-to-rail output; draws 10 mA per amplifier. Needs a 47 pF capacitor between pins 1 and 8 for unity-gain stability (15 MHz uncompensated) and is limited to 16 V total supply.
TL061	JFET	10–30 V	1 MHz	3.5 V/µs	30 nV	0.2 mA	34	JFET input; internally compensated: the board's capacitor across pins 1 and 8 no longer shapes the tone; pins 1, 5, 8 are offset null (1, 5), NC (8). Low-power JFET op-amp at 200 µA; the pin table gives offset null on 1 and 5 though the drawing marks them NC.
741		10–30 V		0.5 V/µs		0.13 mA	256	internally compensated: the board's capacitor across pins 1 and 8 no longer shapes the tone; pins 1, 5, 8 are NC on the D and P packages (offset null on pins 1 and 5 in the PS package). This 2026 revision lists pins 1 and 5 as no-connect on the DIP, so an offset-trim pot there does nothing.
TL071	JFET	4.5–40 V	5.25 MHz	20 V/µs	37 nV	1.4 mA	178	JFET input; internally compensated: the board's capacitor across pins 1 and 8 no longer shapes the tone; pins 1, 5, 8 are NC (offset null on pins 1 and 5 only in the PS package); draws 1.4 mA per amplifier. JFET input; this revision shows pins 1, 5 and 8 as no-connect on the DIP, so no offset trim.
TL081	JFET	4.5–40 V	5.25 MHz	20 V/µs	37 nV	1.4 mA	20	JFET input; internally compensated: the board's capacitor across pins 1 and 8 no longer shapes the tone; pins 1, 5, 8 are NC (offset null on pins 1 and 5 only in the PS package); draws 1.4 mA per amplifier. JFET input; this revision shows no offset-null pins on the DIP.
LF355	JFET	?–36 V	2.5 MHz	5 V/µs	20 nV	2 mA	1	JFET input; internally compensated: the board's capacitor across pins 1 and 8 no longer shapes the tone; pins 1, 5, 8 are offset null (1, 5), NC (8); draws 2 mA per amplifier. Lower-power, slower sibling of the LF356.

Faceplate	Circuit	Based on	Category	Vendor	Box	Knobs	Price	BOM
	ProCo Rat MOJO layout Vero23×17 Verified 2N5484 · UA308 ProCo RAT	ProCo RAT	Distortion	Dirtbox Layouts	—	3	—	24