Marshall JCM900 Schematics

The JCM900 serie amps were introduced in January 1990. They came in two flavors: High Gain Master Volume and High Gain Dual Reverb. The Master Volume amps were more or less a further development of the JCM800 2203/2204 Master Volume amps and they were called the (Hi Gain) Master Volume MkIII amps. The Dual Reverb amps were (losely) based on the JCM800 2205/2210 amps.

The 2100 & 2500 amps were superceded by the JCM900 SL-X amps in 1993.

JCM900 2100 Master Volume, 100W head

The 2100 was introduced in 1990 and discontinued in early 1993.

Schematic of the pre amp with 2x ECC83, CD0109 Issue 4 JMP51A PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0109 Issue 9 JMP51B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 1 JMP50A PCB (Marshall, 1989).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 7 JMP50B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 10 JMP50C PCB (Marshall, 1992).

JCM900 2101 Master Volume, 100W 1×12″ combo

The 2101 was introduced in 1990 and discontinued in 1992. The 2101 was fitted with a 12″ Celestion G12H-100 loudspeaker.

Schematic of the pre amp with 2x ECC83, CD0109 Issue 4 JMP51A PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0109 Issue 9 JMP51B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 1 JMP50A PCB (Marshall, 1989).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 7 JMP50B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 10 JMP50C PCB (Marshall, 1992).

JCM900 2500 Master Volume, 50W head

The 2500 was introduced in 1990 and discontinued in 1992.

Schematic of the pre amp with 2x ECC83, CD0109 Issue 4 JMP51A PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0109 Issue 9 JMP51B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0192 Issue 1 JMP50A PCB (Marshall, 1989).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0112 Issue 7 JMP50B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0112 Issue 10 JMP50C PCB (Marshall, 1992).

Photograph of a JCM900 2500 head.

JCM900 2501 Master Volume, 50W 1×12″ combo

The 2501 was introduced in 1990 and discontinued in 1992.

Schematic of the pre amp with 2x ECC83, CD0109 Issue 4 JMP51A PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0109 Issue 9 JMP51B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0192 Issue 1 JMP50A PCB (Marshall, 1989).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0112 Issue 7 JMP50B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0112 Issue 10 JMP50C PCB (Marshall, 1992).

Photograph of a JCM900 2501 combo.

JCM900 2502 Master Volume, 50W 2×12″ combo

The 2502 was introduced in 1990 and discontinued in 1992.

Schematic of the pre amp with 2x ECC83, CD0109 Issue 4 JMP51A PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0109 Issue 9 JMP51B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0192 Issue 1 JMP50A PCB (Marshall, 1989).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0112 Issue 7 JMP50B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0112 Issue 10 JMP50C PCB (Marshall, 1992).

JCM900 4100 Dual Reverb, 100W head

The 4100 was introduced in 1990 and discontinued in 1999. The 4100 was reissued in 2003.

Schematic of the pre amp with 2x ECC83, CD0189 Issue 1 JMP52A PCB (Marshall, 1989).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 2 JMP52A PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 7-0349 JMP52B PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 7 JMP52C PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, JMP52-02 Issue 10 (Marshall, 1993).

Schematic of the pre amp with 2x ECC83, JMP52-02 Issue 11 (Marshall, 1997).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 1 JMP50A PCB (Marshall, 1989).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 7 JMP50B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 10 JMP50C PCB (Marshall, 1992).

Schematic of the PSU, 4100-60-02 1of2 Issue 11 (Marshall, 1994).

Schematic of the power amp with 1x ECC83 & 4x 5881, 4100-60-02 2of2 Issue 11 (Marshall, 1994).

Schematics of the power amp & PSU with 1x ECC83 & 4x 5881, 4100-60-02 Issue 14 (Marshall, 2002).

Owners manual for the JCM900 4100, 4101, 4102, 4500, 4501, 4502, 2100 SL-X & 2500 SL-X amps.

Photograph of a JCM900 4100 head.

JCM900 4101 Dual Reverb, 100W 1×12″ combo

The 4101 was introduced in 1990 and discontinued in 1999. This combo was fitted with a 12″ Celestion G12H-100 loudspeaker.

Schematic of the pre amp with 2x ECC83, CD0189 Issue 1 JMP52A PCB (Marshall, 1989).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 2 JMP52A PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 7-0349 JMP52B PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 7 JMP52C PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, JMP52-02 Issue 10 (Marshall, 1993).

Schematic of the pre amp with 2x ECC83, JMP52-02 Issue 11 (Marshall, 1997).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 1 JMP50A PCB (Marshall, 1989).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 7 JMP50B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 10 JMP50C PCB (Marshall, 1992).

Schematic of the PSU, 4100-60-02 1of2 Issue 11 (Marshall, 1994).

Schematic of the power amp with 1x ECC83 & 4x 5881, 4100-60-02 2of2 Issue 11 (Marshall, 1994).

Schematics of the power amp & PSU with 1x ECC83 & 4x 5881, 4100-60-02 Issue 14 (Marshall, 2002).

Owners manual for the JCM900 4100, 4101, 4102, 4500, 4501, 4502, 2100 SL-X & 2500 SL-X amps.

JCM900 4102 Dual Reverb, 100W 2×12″ combo

The 4102 was introduced in 1990 and discontinued in 1999. This combo was fitted with two 12″ Celestion (I think 16Ω) G12T-75 loudspeakers.

Schematic of the pre amp with 2x ECC83, CD0189 Issue 1 JMP52A PCB (Marshall, 1989).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 2 JMP52A PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 7-0349 JMP52B PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 7 JMP52C PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, JMP52-02 Issue 10 (Marshall, 1993).

Schematic of the pre amp with 2x ECC83, JMP52-02 Issue 11 (Marshall, 1997).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 1 JMP50A PCB (Marshall, 1989).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 7 JMP50B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 4x EL34, CD0192 Issue 10 JMP50C PCB (Marshall, 1992).

Schematic of the PSU, 4100-60-02 1of2 Issue 11 (Marshall, 1994).

Schematic of the power amp with 1x ECC83 & 4x 5881, 4100-60-02 2of2 Issue 11 (Marshall, 1994).

Schematics of the power amp & PSU with 1x ECC83 & 4x 5881, 4100-60-02 Issue 14 (Marshall, 2002).

Owners manual for the JCM900 4100, 4101, 4102, 4500, 4501, 4502, 2100 SL-X & 2500 SL-X amps.

JCM900 4500 Dual Reverb, 50W head

The 4500 was introduced in 1990 and discontinued in 1999. This amp was fitted with Drake transformers.

Schematic of the pre amp with 2x ECC83, CD0189 Issue 1 JMP52A PCB (Marshall, 1989).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 2 JMP52A PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 7-0349 JMP52B PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 7 JMP52C PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, JMP52-02 Issue 10 (Marshall, 1993).

Schematic of the pre amp with 2x ECC83, JMP52-02 Issue 11 (Marshall, 1997).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0192 Issue 1 JMP50A PCB (Marshall, 1989).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0112 Issue 7 JMP50B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0112 Issue 10 JMP50C PCB (Marshall, 1992).

Schematic of the PSU, 4500-60-02 Issue 10, 1of2 (Marshall, 1994).

Schematic of the power amp with 1x ECC83 & 2x 5881, 4500-60-02 Issue 10, 2of2 (Marshall, 1994).

Owners manual for the JCM900 4100, 4101, 4102, 4500, 4501, 4502, 2100 SL-X & 2500 SL-X amps.

JCM900 4501 Dual Reverb, 50W 1×12″ combo

The 4501 was introduced in 1990 and discontinued in 1999. This amp was fitted with Drake transformers. This combo was fitted with a 12″ Celestion G12T-75 T3781 8Ω speaker.

Schematic of the pre amp with 2x ECC83, CD0189 Issue 1 JMP52A PCB (Marshall, 1989).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 2 JMP52A PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 7-0349 JMP52B PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 7 JMP52C PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, JMP52-02 Issue 10 (Marshall, 1993).

Schematic of the pre amp with 2x ECC83, JMP52-02 Issue 11 (Marshall, 1997).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0192 Issue 1 JMP50A PCB (Marshall, 1989).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0112 Issue 7 JMP50B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0112 Issue 10 JMP50C PCB (Marshall, 1992).

Schematic of the PSU, 4500-60-02 Issue 10, 1of2 (Marshall, 1994).

Schematic of the power amp with 1x ECC83 & 2x 5881, 4500-60-02 Issue 10, 2of2 (Marshall, 1994).

Owners manual for the JCM900 4100, 4101, 4102, 4500, 4501, 4502, 2100 SL-X & 2500 SL-X amps.

Photograph of a JCM900 4501 1×12″ combo.

JCM900 4502 Dual Reverb, 50W 2×12″ combo

The 4502 was introduced in 1990 and discontinued in 1999. This amp was fitted with Drake transformers. This combo was fitted with two 12″ Celestion G12T-75 T3760 16Ω speakers.

Schematic of the pre amp with 2x ECC83, CD0189 Issue 1 JMP52A PCB (Marshall, 1989).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 2 JMP52A PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 7-0349 JMP52B PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, CD0189 Issue 7 JMP52C PCB (Marshall, 1990).

Schematic of the pre amp with 2x ECC83, JMP52-02 Issue 10 (Marshall, 1993).

Schematic of the pre amp with 2x ECC83, JMP52-02 Issue 11 (Marshall, 1997).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0192 Issue 1 JMP50A PCB (Marshall, 1989).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0112 Issue 7 JMP50B PCB (Marshall, 1990).

Schematic of the power amp and PSU with 1x ECC83 & 2x EL34, CD0112 Issue 10 JMP50C PCB (Marshall, 1992).

Schematic of the PSU, 4500-60-02 Issue 10, 1of2 (Marshall, 1994).

Schematic of the power amp with 1x ECC83 & 2x 5881, 4500-60-02 Issue 10, 2of2 (Marshall, 1994).

Owners manual for the JCM900 4100, 4101, 4102, 4500, 4501, 4502, 2100 SL-X & 2500 SL-X amps.

Photograph of a JCM900 4502 2×12″ combo.

JCM900 1912, 1×12″ 150W 8Ω extension cabinet

This 1×12″ extension cabinet was fitted with a 12″ Celestion G12B-150 8Ω speaker.

JCM900 1922, 2×12″ 150W 8Ω mono/stereo extension cabinet

This 2×12″ extension cabinet was fitted with two 12″ Celestion G12T-75 16Ω speakers. This cabinet can be used either as an 8Ω 150W mono cabinet or as a 2x 16Ω 75W stereo cabinet.

JCM900 1936, 2×12″ 150W 8Ω mono/stereo extension cabinet

This 2×12″ extension cabinet was fitted with two 12″ Celestion G12T-75 16Ω speakers. This cabinet can be used either as an 8Ω 150W mono cabinet or as a 2x 16Ω 75W stereo cabinet.

Photograph of a JCM900 1936 cabinet.

JCM900 1960A, 4×12″ 300W 16Ω angled front cabinet.

These 1960 style cabinets were fitted with four 12″ Celestion G12T-75 16Ω speakers.

Photograph of a JCM900 1960A cabinet.

JCM900 1960B, 4×12″ 300W 16Ω straight front cabinet.

These 1960B style cabinets were fitted with four 12″ Celestion G12T-75 16Ω speakers.

JCM900 1960AV, 4×12″ 280W 16Ω angled front cabinet.

These 1960A style cabinets were fitted with four 12″ Celestion G12 Vintage 30 16Ω speakers.

JCM900 1960BV, 4×12″ 280W 16Ω straight front cabinet.

These 1960B style cabinets were fitted with four 12″ Celestion G12 Vintage 30 16Ω speakers.