Enclosure not stated · 4 knobs

BOSS DR-55

Based on the Boss DR-55

Category: Ring Mod / Synth· Full Synths Drum Synths and Misc Synth
Controls: Volume · Tone · Tempo · Accent
Price: see vendor
Tags: Full Synths Drum Synths and Misc Synth

Open the schematic at Experimentalists Anonymous

Schematic

The schematic is the archived file. Open it at Experimentalists Anonymous, or browse its folder.

Parts list 205 rows

Report a wrong parse

Got parts in a drawer? See what you can build with them.

Check before you build · 3 values the reader of this schematic was not sure of

Q1, Q2, Q4-Q12: transistor types not given on the drawing
R28, R78, R85: each designator printed twice with different values
Tempo/Accent pot taper letter C as drawn

Ref	Value	Normalized	Type	Notes
Resistors 102
R1	1k	1k		read from the schematic by eye
R4	10k	10k		read from the schematic by eye
R5	2.2M	2.2M		read from the schematic by eye
R6	22k	22k		read from the schematic by eye
R7	22k	22k		read from the schematic by eye
R8	22k	22k		read from the schematic by eye
R9	22k	22k		read from the schematic by eye
R10	150k	150k		read from the schematic by eye
R11	680k	680k		read from the schematic by eye
R12	820	820		read from the schematic by eye
R13	2.2M	2.2M		read from the schematic by eye
R14	100k	100k		read from the schematic by eye
R15	68k	68k		read from the schematic by eye
R16	680k	680k		read from the schematic by eye
R17	1k	1k		read from the schematic by eye
R18	2.2M	2.2M		read from the schematic by eye
R19	10k	10k		read from the schematic by eye
R20	100	100		read from the schematic by eye
R21	100k	100k		read from the schematic by eye
R22	1k	1k		read from the schematic by eye
R23	330	330		read from the schematic by eye
R24	1k	1k		read from the schematic by eye
R25	10k	10k		read from the schematic by eye
R26	180k	180k		read from the schematic by eye
R27	330	330		read from the schematic by eye
R28	2.2M	2.2M		designator R28 printed twice; this one is the 2.2M base resistor of Q10; read from the schematic by eye
R28	22k	22k		designator R28 printed twice; this one is the 22k to ground in the SD filter; read from the schematic by eye
R29	22k	22k		read from the schematic by eye
R30	470k	470k		read from the schematic by eye
R31	33k	33k		read from the schematic by eye
R32	120k	120k		read from the schematic by eye
R33	2.2M	2.2M		read from the schematic by eye
R34	1M	1M		read from the schematic by eye
R35	10k	10k		read from the schematic by eye
R36	10k	10k		read from the schematic by eye
R37	10k	10k		read from the schematic by eye
R38	47k	47k		read from the schematic by eye
R39	47k	47k		read from the schematic by eye
R40	10k	10k		read from the schematic by eye
R41	47k	47k		read from the schematic by eye
R42	270	270		read from the schematic by eye
R43	2.2M	2.2M		read from the schematic by eye
R44	22k	22k		read from the schematic by eye
R45	22k	22k		read from the schematic by eye
R46	33k	33k		read from the schematic by eye
R47	100k	100k		read from the schematic by eye
R48	33k	33k		read from the schematic by eye
R49	10k	10k		read from the schematic by eye
R50	2.2M	2.2M		read from the schematic by eye
R51	2.2M	2.2M		read from the schematic by eye
R52	10k	10k		read from the schematic by eye
R53	47k	47k		read from the schematic by eye
R54	10k	10k		read from the schematic by eye
R55	1M	1M		read from the schematic by eye
R56	2.2M	2.2M		read from the schematic by eye
R57	82k	82k		read from the schematic by eye
R59	1M	1M		read from the schematic by eye
R60	1k	1k		read from the schematic by eye
R61	470k	470k		read from the schematic by eye
R62	470k	470k		read from the schematic by eye
R63	470k	470k		read from the schematic by eye
R64	470k	470k		read from the schematic by eye
R65	220k	220k		read from the schematic by eye
R66	100k	100k		read from the schematic by eye
R67	100k	100k		read from the schematic by eye
R68	100k	100k		read from the schematic by eye
R69	100k	100k		read from the schematic by eye
R70	100k	100k		read from the schematic by eye
R71	100k	100k		read from the schematic by eye
R72	100k	100k		read from the schematic by eye
R73	82k	82k		read from the schematic by eye
R74	22k	22k		read from the schematic by eye
R75	68k	68k		read from the schematic by eye
R76	470k	470k		read from the schematic by eye
R77	220K	220k		on foil side; read from the schematic by eye
R78	100k	100k		designator R78 printed twice; this one is at the flip-flop gate input; read from the schematic by eye
R78	1M	1M		designator R78 printed twice; this one is across C41; read from the schematic by eye
R79	15K	15k		serial-number table: 6.8K up to 923500, 15K from 923600; read from the schematic by eye
R80	1M	1M		read from the schematic by eye
R81	22k	22k		serial-number table: 22K up to 923500, 47K from 923600; read from the schematic by eye
R82	33k	33k		read from the schematic by eye
R83	33k	33k		read from the schematic by eye
R85	6.8k	6.8k		designator R85 printed twice; this one is the pull-up at the start/stop node; read from the schematic by eye
R85	470k	470k		designator R85 printed twice; this one is in the Q18 Schmitt trigger; read from the schematic by eye
R86	68k	68k		read from the schematic by eye
R87	33k	33k		read from the schematic by eye
R88	10k	10k		read from the schematic by eye
R89	100k	100k		read from the schematic by eye
R90	10k	10k		read from the schematic by eye
R91	100k	100k		read from the schematic by eye
R92	10k	10k		read from the schematic by eye
R93	100k	100k		read from the schematic by eye
R94	330k	330k		read from the schematic by eye
R95	82k	82k		read from the schematic by eye
R96	33k	33k		read from the schematic by eye
R97	560	560		read from the schematic by eye
R98	100k	100k		read from the schematic by eye
R99	10k	10k		read from the schematic by eye
R100	1K	1k		on foil side; read from the schematic by eye
R101	22K	22k		read from the schematic by eye
R102	68K	68k		read from the schematic by eye
×1	220k	220k		undesignated, Q1 base bias in BD voice; read from the schematic by eye
Capacitors 47
C1	.047uF	47n		read from the schematic by eye
C2	.068uF	68n		read from the schematic by eye
C3	.068uF	68n		read from the schematic by eye
C4	.068uF	68n		read from the schematic by eye
C5	.068uF	68n		read from the schematic by eye
C6	.15uF	150n		drawn .15/35, 35V tantalum; read from the schematic by eye
C7	22uF	22u		drawn 22/10, 10V electrolytic; read from the schematic by eye
C8	4.7uF	4.7u		drawn 4.7/35, 35V electrolytic; read from the schematic by eye
C9	4.7uF	4.7u		drawn 4.7/35, 35V electrolytic; read from the schematic by eye
C10	.0018uF	1.8n		read from the schematic by eye
C11	4.7uF	4.7u		drawn 4.7/35, 35V electrolytic; read from the schematic by eye
C12	22uF	22u		drawn 22/10, 10V electrolytic; read from the schematic by eye
C13	22uF	22u		drawn 22/10, 10V electrolytic; read from the schematic by eye
C14	22uF	22u		drawn 22/10, 10V electrolytic; read from the schematic by eye
C15	.0068uF	6.8n		read from the schematic by eye
C16	.0068uF	6.8n		read from the schematic by eye
C17	.0068uF	6.8n		read from the schematic by eye
C18	.0047uF	4.7n		read from the schematic by eye
C19	.027uF	27n		read from the schematic by eye
C20	.0056uF	5.6n		read from the schematic by eye
C21	.0047uF	4.7n		read from the schematic by eye
C22	.001uF	1n		read from the schematic by eye
C23	.0022uF	2.2n		read from the schematic by eye
C24	4.7uF	4.7u		drawn 4.7/35, 35V electrolytic; read from the schematic by eye
C25	.0022uF	2.2n		read from the schematic by eye
C26	.027uF	27n		read from the schematic by eye
C27	.0022uF	2.2n		read from the schematic by eye
C28	.001uF	1n		read from the schematic by eye
C29	.0022uF	2.2n		read from the schematic by eye
C30	.0015uF	1.5n		read from the schematic by eye
C31	.0015uF	1.5n		read from the schematic by eye
C32	47P	47p		read from the schematic by eye
C33	.0027uF	2.7n		read from the schematic by eye
C34	.0022uF	2.2n		read from the schematic by eye
C35	.0068uF	6.8n		read from the schematic by eye
C36	.001uF	1n		read from the schematic by eye
C37	.018uF	18n		read from the schematic by eye
C38	.047uF	47n		read from the schematic by eye
C39	22uF	22u		drawn 22/10, 10V electrolytic; read from the schematic by eye
C40	100P	100p		read from the schematic by eye
C41	1uF	1u		drawn 1/50, 50V electrolytic; read from the schematic by eye
C42	1uF	1u		non-polar, drawn 1/50; serial-number table: 1mfd NP up to 923500, 0.47mfd NP from 923600; read from the schematic by eye
C43	.47uF	470n		drawn .47/50, 50V electrolytic; read from the schematic by eye
C45	.47uF	470n		drawn .47/50, 50V electrolytic; read from the schematic by eye
C46	.0033uF	3.3n		read from the schematic by eye
C47	330P	330p		read from the schematic by eye
C48	10uF	10u		drawn 10/16, 16V electrolytic; read from the schematic by eye
Diodes 19
D1	Diode	DIODE		no part number given; read from the schematic by eye
D2	Diode	DIODE		no part number given; read from the schematic by eye
D3	Diode	DIODE		no part number given; read from the schematic by eye
D4	Diode	DIODE		no part number given; read from the schematic by eye
D5	Diode	DIODE		no part number given; read from the schematic by eye
D6	Diode	DIODE		no part number given; read from the schematic by eye
D7	Diode	DIODE		no part number given; read from the schematic by eye
D8	Diode	DIODE		no part number given; read from the schematic by eye
D9	Diode	DIODE		no part number given; read from the schematic by eye
D10	Diode	DIODE		no part number given; read from the schematic by eye
D11	Diode	DIODE		no part number given; read from the schematic by eye
D12	Diode	DIODE		no part number given; read from the schematic by eye
D13	Diode	DIODE		no part number given; read from the schematic by eye
D14	Diode	DIODE		no part number given; read from the schematic by eye
D15	Diode	DIODE		no part number given; read from the schematic by eye
D16	Diode	DIODE		no part number given; read from the schematic by eye
D17	Diode	DIODE		no part number given; read from the schematic by eye
D18	Diode	DIODE		no part number given; read from the schematic by eye
D19	Diode	DIODE		no part number given; read from the schematic by eye
Transistors 18
Q1	?	?		NPN, BD voice transistor, no part number given; read from the schematic by eye
Q2	?	?		NPN, BD voice transistor, no part number given; read from the schematic by eye
Q3	2SK30A	2SK30A		rank (O); N-JFET accent VCA; 2SK30A-Y with VR6 on units up to serial 912800; read from the schematic by eye
Q4	?	?		NPN, output stage transistor, no part number given; read from the schematic by eye
Q5	?	?		NPN, DBS sync output transistor, no part number given; read from the schematic by eye
Q6	?	?		NPN, rim shot voice transistor, no part number given; read from the schematic by eye
Q7	?	?		NPN, hi-hat voice transistor, no part number given; read from the schematic by eye
Q8	?	?		NPN, noise source transistor, no part number given; read from the schematic by eye
Q9	?	?		NPN, noise amp transistor, no part number given; read from the schematic by eye
Q10	?	?		NPN, SD voice transistor, no part number given; read from the schematic by eye
Q11	?	?		NPN, SD voice transistor, no part number given; read from the schematic by eye
Q12	?	?		NPN, hi-hat buffer transistor, no part number given; read from the schematic by eye
Q13	2SC945	2SC945		legend Q13-17: 2SC945 P or Q; read from the schematic by eye
Q14	2SC945	2SC945		legend Q13-17: 2SC945 P or Q; read from the schematic by eye
Q15	2SC945	2SC945		legend Q13-17: 2SC945 P or Q; read from the schematic by eye
Q16	2SC945	2SC945		legend Q13-17: 2SC945 P or Q; read from the schematic by eye
Q17	2SC945	2SC945		legend Q13-17: 2SC945 P or Q; read from the schematic by eye
Q18	2SA733	2SA733		rank (P), PNP; read from the schematic by eye
ICs 3
IC1	TC5501P-1	TC5501P-1		256x4 CMOS RAM, pattern memory; read from the schematic by eye
IC2	MC14520B	MC14520B		dual binary counter; read from the schematic by eye
IC3	CD4011UB	CD4011UB		quad NAND; TC4011UBP or CD4011B from serial 923600; read from the schematic by eye
Inductors 1
L1	45mH	45mH		hi-hat resonator; read from the schematic by eye
Potentiometers 4
Volume	A10K	A10k	Potentiometer	VR2, drawn 10kA, with power switch S8; read from the schematic by eye
Tone	A1M	A1M	Potentiometer	VR1, drawn 1MA; read from the schematic by eye
Tempo	C500K	C500k	Potentiometer	VR3, drawn 500kC; 1MC from serial 923600; read from the schematic by eye
Accent	C500K	C500k	Potentiometer	VR4, drawn 500kC; read from the schematic by eye
Trimmers 3
Noise	B10K	10k		VR7, drawn 10kB; read from the schematic by eye
VR5	1KB	1k		BD trim, units up to serial 912800 only (replaced by R12 820); read from the schematic by eye
VR6	B50K	50k		accent adj., units up to serial 912800 only (replaced by R101/R102); read from the schematic by eye
Switches 7
S1	SP4T	SP4T		Sound select BD/SD/RS/AC; read from the schematic by eye
S2	4PDT	4PDT		Mode play/write; read from the schematic by eye
S3	SP3T	SP3T		Variation A/AB/B; read from the schematic by eye
S4	SP3T	SP3T		Hi hat 16/8/off; read from the schematic by eye
S5	SPST	SPST		Start pushbutton, momentary; read from the schematic by eye
S6	SPST	SPST		Stop pushbutton, momentary; read from the schematic by eye
S7	SP8T	SP8T		Rhythm select, 8 positions; read from the schematic by eye
LEDs 1
D20	TLR124	TLR124		tempo LED; read from the schematic by eye