Marshall 18 Watt Combo Schematic

A 280v

C2 16-32F/450v R7 100K R6 8.2K/2W C20-B 16F/350v C16.01F C17.01F

Revision 5

C20-A 32F/350v
R3W R21 8.2K C3 50-500F/50v

R5 1.5K-2K/2W

R18 100K

R19 100K

V4 EL84 7

SW2 Standby (SPST)

SW4 Speaker Impedance ~15 (16) Ohm Selector (SP3T) ~7 (8) Ohm ~3 (4) Ohm 0 (Gnd) 6.3v Heater Filaments 1

V6 EZ81

300v 300v 6.3v

N O R J2 M A L HI

R3 1Meg R4 1Meg R2 820

V1 ECC83

C11 50F 25v

C6.01F R30 Tone

C5.005F C1.01F 2 R1 100K

V2 ECC83

V2A 1 V2B 3 R820

R17 47K

SW5 Power Selector 240v (SP3T) 220v 200v

500K-A

C18.022F R23 470K
R20 125/5W R22 8.2K R15 R16

Volume

R29 470K

C15.005F

500K-A R9 470K

I1 Power Lamp 6.3v 8 7

SW1 Power On/Off (SPST)

R12 220K

R11 100K

T R E LO M O J4 L O

R8 1Meg

R27 68K R28 68K

C12.005F C9.01F R24 470K R33 C10.01F R34 C14 470pF

V3 ECC83

1 V3B 2

C8.01F

F1 ~1A SloBlow Fuse

C7.05F

C19 50F 25v

RR10 2.2Meg 820

R26 1Meg

Intensity

1K-L SW3 External Foot Switch (SPST)

2Meg-A

C13.005F
E Z81/6CA4 Pinout 1 = Anode 2 = No Connection 3 = Cathode 4 = Heater 5 = Heater 6 = No Connection 7 = Anode (2nd) 8 = No Connection 9 = No Connection
E CC83/12AX7 Pinout 1 = Anode (2nd) 2 = Grid 1 (2nd) 3 = Cathode (2nd) 4 = Heater 5 = Heater 6 = Anode 7 = Grid = Cathode 9 = Heater Tap
E L84/6BQ5 Pinout 1 = Internal Connection 2 = Grid = Cathode 4 = Heater 5 = Heater 6 = Internal Connection 7 = Anode 8 = Internal Connection 9 = Grid 2
Components have been numbered for reference purposes only. All capacitors are rated for at least 400V unless otherwise noted. All resistors are rated Watt unless otherwise noted.
Notes: 1. Some 18Watt Marshall combos came equipped with 1Meg Volume and Tone Potentiomenters (R30, 31, 34, 35). 2. Components with more than one value (R5, C2, C3) are the result of production variations. The differing values listed have been observed in authentic unmodified examples of this amplifier circuit. Experiment! top 3. Capacitor C4 has been intentionally omitted from the numbering scheme. S looking. :^ )

V5 EL84

From 6.3v Filament Heater Supply

V4 EL84

V3 12AX7

V2 12AX7

V1 12AX7
Note: Pins 4 and 5 of V6 (EZ81) Rectifier connect to a separate 6.3v filament supply as illustrated in the main schematic.

Filament Connections

WARNING!
This document is distributed for educational purposes ONLY. The components specified in this schematic utilize POTENTIALLY FATAL HIGH VOLTAGES. Maintenance and repair of all equipment utilizing hazardous voltages must be referred to a properly trained and qualified technician. PedalMonkey.com expressly disclaim all liability for injury or property damage resulting from the misuse of any information contained in this document.
This document and the illustrations contained herein are the property of PedalMonkey. Permission is not granted to make printed copies of this document or any portion thereof for the purpose of distribution. Further, electronic distribution of this document from any domain other than www.pedalmonkey.com without the expressed permission of PedalMonkey is prohibited. The name Marshall is the property of Marshall Amplification.

2001 PedalMonkey

Tube-Map
V2203/1959HW 1959SLP 1974X 1987X 2061X JTM 45 DSL100 DSL401 DSL50 TSL100 TSL122 TSL60 Series EL100/100 EL50/50 TS 12AX7-V1 JJ12AX7 JJ12AX7 JJ12AX7 EH12AT7 EH12AT7 JJ12AX7 JJ12AX7 JJ12AX7 JJ12AX7 EH12AT7 EH12AT7 JJ E34L JJ E34L JJ E34L JJ E34L JJ E34L TT E83CC-V1 TT12AX7 JJ12AX7 JJ12AX7 JJ12AX7 Fat TTE83CC-V1 Tight / Heavy TT12AX7-V1 JJ 12AX7 V2 V3 JJ 12AX7 JJ 12AX7 JJ 12AX7 JJ 12AX7 JJ 12AX7 JJ 12AX7 JJ 12AX7 JJ 12AX7 JJ 12AX7 JJ EL84 TT12AX7 V4 Ru 5881 WGC TT EL34 TT 12AX7 TT 12AX7 Ru 5881 WGC SED EL34 JJ E34L JJ EL84 JJ EL84 JJ EL84 TT KT66 TT KT66 JJ E34L JJ EL84 JJ EL84 JJ E34L JJ E34L JJ E34L JJ E34L JJ E34L JJ E34L JJ E34L JJ E34L JJ E34L JJ E34L JJ E34L JJ E34L JJ EL84 JJ EL84 JJ E34L JJ E34L JJ E34L JJ E34L JJ E34L JJ EL84 JJ E34L JJ EL84 V5 Ru 5881 WGC TT EL34 JJ 12AX7 JJ 12AX7 Ru 5881 WGC SED EL34 JJ E34L JJ EL84 JJ EL84 V6 JJ 12AX7 TT EL34 TT EL34 TT EL34 Ru 5881 WGC SED EL34 JJ E34L EH EZ81 V7 JJ 5AR4 TT EL34 TT EL34 TT EL34 Ru 5881 WGC SED EL34 JJ E34L TT EL34 TT EL34 V8 V9 V10 V11
AVT Series BS150 JMP1 TT E83CC-V1 JJ12AX7
Smooth JJ 12AX7-VFat TTE83CC-V1 TTE83CC-V1 JJ12AX7 JJ12AX7 JJ12AX7 JJ12AX7 TT12AX7 SO 5881 WGC SO 5881 WGC SO 5881 WGC SO 5881 WGC