Understanding your studio JTM

Posted: 1st August 2023

When you think of Marshall, you think of iconic sound that transcends eras, the Studio JTM gives you just that. It celebrates the heritage of rock by providing the same legendary tones as the original JTM in a significantly lighter, more compact format.

Read time: 3 mins

A welcome addition to the Studio series, the all-valve Studio JTM offers players authentic, smooth, valve-driven break-up at lower volumes, making it perfect for home or studio use. Handcrafted in the UK for players who want to go from a clean, with some character, straight through to old school overdriven sounds.  The Studio JTM is also great for players that are after a compact combo amp or a head to pair with a Studio cabinet for a small but perfectly formed Marshall rig.


The Studio JTM is equipped with built-in power reduction technology, allowing players to effortlessly swap between 20 watts and 5 watts at the flick of a switch in various playing situations. With this range, players can achieve those same huge guitar tones but at a more controllable level without having to compromise on tone, whether you’re playing at home, in the studio or at an intimate gig.

The ST112 and ST212 cabs, as well as the ST20C combo feature 12” Celestion G12M-65 Creamback speakers. These speakers are essential for creating that definitive vintage ‘Plexi’-style tone, the same tone that sprung Marshall to the forefront of rock ‘n’ roll in the sixties. 

Both the ST20H and ST20C feature two vintage voicings – one ‘normal’ and the other ‘high treble’. The high treble inputs produce brighter, more aggressive tones, whereas the normal inputs are rounder and warmer in tone - both voices have high and low sensitivity inputs to suit different guitars. For higher gain, plug your guitar into the high-sensitivity input, and for cleaner tones, plug into the low-sensitivity input. Players can also blend these two voices together by jumping the channels using a ¼” patch cable. Both the high treble and normal inputs volume can be adjusted using the respective controls (i.e., loudness 1 & 2).

Hear the Studio JTM

ST20H - Clean
ST20H - Clean Presence 6, Bass 5, Mid 4, Treble 6, High Treble 6, Normal 5 (Singlecoil strat)
ST20H - Crunch
ST20H - Crunch Presence 7, Bass 3, Mid 6, Treble 7, High Treble 10, Normal 4 (HSS strat style)
ST20C - Clean
ST20C - Clean Presence 7, Bass 5, Mid 6, Treble 7, High Treble 3, Normal 1 (Singlecoil strat)
ST20C - Crunch
ST20C - Crunch Presence 7, Bass 2, Mid 6, Treble 7, High Treble 8, Normal 1 (HSS strat style)

Part of a responsive and dynamic amp range, the Studio JTM allows the sound of the player's hands and the guitar to come through. To create those crunchy tones that Marshall is known for, plug into the high-sensitivity high treble input and increase the presence, increasing the high frequencies will add more bite to your sound. As you increase the high treble (loudness 1) control, your tone will become increasingly crunchy and overdriven – perfect for players that want that classic rock sound. Whereas to get clean tones, plug into the low-sensitivity normal input, reduce the presence while adjusting the bass, middle, and treble controls so they’re around the halfway point, and you’ll be producing rich, warm tones in no time. This is ideal for players that want to create smooth jazz tones or players who want those edge-of-breakup tones. 


Two features of the Studio JTM head and combo that were not present on the original JTM, are the DI out and FX loop, bringing the JTM into the present day. Utilising the emulated DI output allows players to send the signal directly to connect the amp to an external recording device or mixing desk, bypassing the amp's speaker and resulting in a cleaner signal sound. This is great for players that want to record their own music and is ideal for live performances.

Thanks to the newly added series FX loop, players can now add pedals and effects after the preamp stage but before the power amp stage, as opposed to running gear solely through the front end of the amp. Using the switch on the rear panel, the FX loop can be completely removed from the signal path when switched off. We recommend using the Bluesbreaker and the Guv’nor reissue pedals with the Studio JTM range to produce smooth overdriven tones with a touch of compression.