Marshall ST20H Studio JTM 20W Guitar Amplifier Head

Marshall ST20H Studio JTM 20W Guitar Amplifier Head
Product no: 9000-0115-0228 Bax Music Warranty: This product comes with a 3-year warranty, the tubes come with a 3-month warranty.

General

The Marshall Studio JTM Series ST20H amplifier head features a compact, single-channel design and serves up a solid range of vintage JTM-style sounds. Loaded with ECC83 preamp tubes and 5881 power amp tubes, this 20-Watt guitar amp head can deliver classic crunch as well as tight cleans, and can even be toned down to a 5-Watt output as needed.

The ST20H Studio JTM: A Superb UK-Built Pedal Platform

Equipped with an effects loop, this amp head is happy to process your favourite effect pedals and, while the housing is a bit more compact compared to the original JTM heads, the whole thing is skilfully put together in the same UK factory as its esteemed predecessors. Finished with a DI output, the ST20H is ready for practice sessions and gigs alike.

Specifications

Product features

Sustainable product	not specified
Amplifier type	tube
Power in Watts	16 - 20 Watts
Speaker output impedance	16 Ohms, 8 Ohms, 4 Ohms
Weight	5 - 9.9 kg
Number of speaker outputs	5
Number of channels	1
Amplifier valve	5881
Amp modelling	no
Built-in tuner	no
Built-in effects	none
Power attenuator	yes
Effects loop	yes
Connectors	External speaker(s), Line-out
Colour	black

Weight and dimensions including packaging

Weight (incl. packaging)	12,1 kg
Dimensions (incl. packaging)	74,0 x 40,5 x 31,0 cm

Product specifications

Marshall guitar amplifier head
- model: ST20H
- series: Studio JTM
electronics
- power output: 20W or 5W
- preamplifier tubes: 3x ECC83 (1x phase splitter)
- power amp tubes: 2x EL5881
- channels: 1
front panel
- controls:
  - normal / loudness 2
  - high treble / loudness 1
  - treble
  - middle
  - bass
  - presence
- switches:
  - on / off
  - high / standby / low
  - fx loop on / off
connections:
- 2x 6.35mm TS jack input 1
- 2x 6.35mm TS jack input 2
- FX loop return/send (2x 6.35mm jack)
- 6.35mm jack fx loop return
- 6.35mm jack fx loop send
- 6.35mm jack DI out
- 5x 6.35mm jack speaker out
  - 1x 4 Ohm
  - 2x 8 Ohm
  - 1x 8 Ohm
  - 2x 16 Ohm
  - 1x 16 Ohm
- power cable
housing
- classic JTM look
- handle: on top
- dimensions: 500 x 240 x 230mm
- weight: 9.25 kg
includes power cable

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Dominiek Denolf June 19, 2026

Wrote the following about Marshall ST20H Studio JTM 20W Guitar Amplifier Head

Supersnel geleverd, S'avonds besteld, dag erop s'morgens in huis. De jtm45 in 20 watt amp, of 5 watt keuze. Echt power, een zee van low end en smooth high end. Perfecte pedal platform amp.