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Marshall ST20H Studio JTM 20-watt Amplifier Head

20W, 2-channel Tube Guitar Amp Head with 3-band EQ, Presence, DI Out, Power Selection, and FX Loop
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Item ID: ST20H
Marshall ST20H Studio JTM 20-watt Amplifier Head
Price:$1,349 and 99 cents
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Marshall ST20H Studio JTM 20-watt Amplifier Head
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Marshall ST20H Studio JTM 20-watt Amplifier Head
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Price:$1,349 and 99 cents
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A Return to Marshall’s JTM Roots

Marshall’s Studio series has long served as a Sweetwater favorite, as it perfectly packs many of the company’s iconic amplifier models down into compact, gig-and-studio-ready combos and heads. From the Super Lead to the Silver Jubilee, the Studio series encompasses almost the entirety of Marshall’s long history — with the ST20H Studio JTM, it reaches all the way back to the beginning. This 20-watt amplifier head precisely replicates the creamy highs, loose lows, and smoky overdriven tone of the original Marshall 2245 — the platform that arguably defined the biting sound of British blues rock while setting the stage for Marshall’s later amplifier creations. Plus, while it’s certainly a vintage throwback, the ST20H Studio JTM comes equipped with all the Studio series’ usual bells and whistles, including a 5-watt power scaling mode, effects loop, and speaker-emulated DI output. Complete with vintage-inspired touches from the metal “coffin”-style logo to the levant front covering, the UK-built ST20H Studio JTM is a top-tier tonal tribute to the model that began the Marshall legend.

A tonal tribute to Marshall’s famed 2245/JTM 45

More than just an aesthetic tribute to Marshall’s early days, the ST20H Studio JTM’s dual 5881 power tubes and trio of ECC83 preamp and phase inverter tubes match the original 2245. In comparison to the later EL34-equipped Marshall models that would define hard rock in the 1970s, the ST20H Studio JTM’s tone harkens back to the birth of British blues-rock, perfectly capturing the loose bass, rounder response, and compelling natural compression of its JTM inspiration. Overall, the ST20H Studio JTM supplies an extraordinarily versatile tube tone that can take you from stadium-ready power-chord rhythms to dark, moody blues lines without breaking a sweat. And if you’re after just a touch more control, Sweetwater guitarists recommend trying out the time-tested trick of patching both channels together and blending their tones.

Loaded with all the player-friendly features you need

Consider yourself lucky, because the Marshall ST20H Studio JTM sports plenty of onboard features not found on the original 2245. An onboard effects loop makes integrating your pedals and external processors a breeze. Attaining cranked tones at listenable volumes is a breeze thanks to a power reduction circuit. You also get a speaker-emulated DI output for easy recording or routing to a PA. You’ll value the ST20H Studio JTM's modern flexibility almost as much as you appreciate its classic tone.

Early-era Marshall aesthetics

Far from the later Plexi-equipped, script-logo Marshalls that we all know and love, the Studio JTM series reaches back to an earlier time in the Marshall legend — when Marshall amps still wore their American influence on their sleeve. This amp’s levant front covering, gold piping/beading, and handsome metal Marshall “coffin” logo look as though they rolled right out of Jim Marshall’s workshop, beaming with early 1960s style. And perhaps best of all, the ST20H Studio JTM boasts a high-end enclosure crafted from finger-jointed plywood for a lighter weight and superior sound.

Marshall ST20H Studio JTM Features:

  • 2-ch, 20W tube amp head inspired by Marshall’s early 2245 model
  • 2 x 5881 power tubes, 2 ECC83 preamp tubes, and an ECC83 phase splitter capture the creamy highs, loose lows, and exceptionally dynamic overdrive of the original JTM
  • High Treble and Normal channels can be patched together for endless tonal experimentation
  • 3-band EQ and Presence knob dial in your sound to perfection
  • Speaker-emulated DI output for easy recording and straight-to-PA gigging
  • FX loop makes it a breeze to integrate your favorite time-based and modulation pedals
  • JTM-inspired aesthetics, including levant front covering, a metal “coffin” logo, gold piping, and fawn fret
  • Premium finger-jointed plywood enclosure
  • Handbuilt in the UK Marshall factory

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Tech Specs

  • Type: Tube
  • Number of Channels: 2
  • Output Power: 20W (5W)
  • Preamp Tubes: 2 x 12AX7 (preamp), 1 x 12AX7 (phase)
  • Power Tubes: 2 x 5881
  • EQ: 3-band EQ, Presence Control
  • Inputs: 2 x 1/4" (High Treble), 2 x 1/4" (Normal)
  • Outputs: 5 x 1/4" (4/8/16 ohms), 1 x 1/4" (DI out)
  • Effects Loop: Yes (on/off switch)
  • Power Source: Standard IEC AC cable
  • Height: 9.4"
  • Width: 19.7"
  • Depth: 9.1"
  • Weight: 20.4 lbs.
  • Manufacturer Part Number: ST20H-U

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Reviews

Solid Amp
This is a great sounding amp with a vintage sound and feel. It's based on the Bassman/JTM circuit which has great warm clean sounds. There have been comments that, when overdriven, this amp gets bassy and muddy. I wouldn't disagree with that, although that is part of the design. If you want stage volume clean sounds that keep up with a drummer in a club, why on earth would you buy this amp? If you play smaller gigs, or at home, or even DI or at lower volumes, or want a solid pedal platform, this amp is great. Also, if you play loud with a single coil guitar like a strat, this amp is amazing. That "muddy" bass breaks up in a fuzzy way that sounds beautiful. But really, you have to turn the volume knob up to at least half way, maybe 2 o'clock to get over driven sounds. Lots of headroom. At 20 watts, this amp is easily into the 90-100 DB range before the bass starts to loosen up. Effects loop is very quiet and usable. I very much enjoy the switchable 5W mode to take a little volume and headroom down, when needed. I like the extra standby mode switch. EQ is very effective. Internally, tubes are upright (a design plus). And it just looks awesome. If you want a big stage amp, high volume cleans, high volume humbucker cleans, as well as a very quiet amp, this amp is not for you. If you're a home or small venue rocker or want a good pedal platform with a vintage Marshall flavor, this is a great amp.
Incredible JTM Amp!
Marshall has captured the JTM45 wonderfully in this unit. It's so much more musical than my other amps (fender deluxe reverb and Vox AC15), and a big range of cleans to edge of breakup that can be dialed in with blending the 2 channels, the EQ pots, and the presence. I paired it with the Marshall 2x12 creamback cab, and the Marshall 1959 pedal for the option of those badass plexi sounds. Its also beautiful to look at, and finish quality is impeccable. Thanks to Kris Eckman for setting me up with a great deal on the package!!
marshall st20
I got my first Marshall in 1970 I was 18 . It was a 50 watt tremolo head with an 8X10 CAB. A have had a whole lot of different Marshall over the decades. I know which models work best for me. I like the traditional models . I did tour with a couple of silver jubilee 2553. I need to run a pedal rig. The st20h is perfect . It has lots of headroom. It has a great feel . The thing is just so pretty too. I play 90s country 80s metal all kinds of Blues, and this amp is perfect. Currently I have it plugged into a Marshall stereo 4x12 wit G1225H SPEAKERS. I recently went to see Bonnie Raitt. Her Guitarist; Duke Levine was using one with mostly a tele. If You have one of these amps You would have spotted it even if You couldn;t see it. It's got it's own thing. I recently saw a video of Tom Bukovac in the studio He had one also.. I can't say enough good things. PS Ive been shopping with Sweetwater close to 25 years now. I love it. My Salesman Charles Dent has become a Buddy, and even bullshits with me about gear.
Music background: 50 years pro experience
Fantastic Amp!
I purchased the combo that was an open box (I could not find any issues with it). The amp has a fantastic clean sound and my Duelist pedal sounds fantastic with it. Very happy with the purchase.
Quality Marshall Amp
The Marshall ST20H Studio amp is a great sounding amp. I have played it through a variety of speakers, and it sounds great through all of them. Plenty of headroom power to cut through a drummer. Everything feels high quality on this amp and all of the Marshall Studio amps. Logan Miller always hooks me up with great service and fast shipping.
Music background: Seasoned Musician

There are countless "British"-style guitar amplifiers out there, but take it from the lifelong guitarists and tone connoisseurs at Sweetwater, when it comes to Marshall tone, there's nothing like the real thing. We've played them all, from vintage JTM45s and the ultra-cool Plexi reissue to modern handmade masterpieces such as the JVM410. There isn't a model among them we can't recommend with total confidence, and that includes their more affordable models too, like MG, DSL, and Code series amps. Thanks to our tight relationship with Marshall, Sweetwater's always on the cutting edge of their latest designs, custom models, and limited-edition gems. If you want iconic tone from across the pond, you want Marshall, and your Sweetwater Sales Engineer will help you find the perfect one.