Marshall ST20C Studio JTM 1 x 12-inch 20-/5-watt Tube Combo Amplifier Reviews
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 ST20C Studio JTM, it reaches all the way back to the beginning. This 20-watt, 1 x 12-inch combo amplifier 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 also setting the stage for Marshall’s later amplifier creations. Plus, while it’s certainly a vintage throwback, the ST20C Studio JTM comes equipped with all the Studio series’ usual bells and whistles, including a 5-watt power scaling mode, FX loop, and speaker-emulated DI output. Vintage-inspired from the metal “coffin”-style logo to the levant front covering, the UK-built ST20C Studio JTM is a top-tier tonal tribute to the model that began the Marshall legend.
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Highest Rated Reviews
This is THE amp!
This is one of those amps that you can plug your guitar into with all the amp's knobs can be at noon and it will sound glorious. There's no unusable setting, it's never too harsh and remains full regardless of where the eq is set, the amp just doesn't sound bad.
If someone uses this amp and says they are getting a bad sound out of it, I'd wager they most likely don't know what they're doing.
The Celestion Creamback 65 speaker is the best speaker for a Vintage Marshall type amp. It takes the Harsh frequencies and tames then into something musical. I would not like this speaker in a Fender-type amp, but it suits a vintage Marshall amp perfectly.
The cab is wide and thick, there's a depth to that which gives the amp a bigger sound, maybe this influences the amp's feel. It sounds and feels much bigger than it looks, has the feel of a cranked Marshall through a half-stack, I feel.
This amp is for someone who wants the REAL deal. There are tons of clones of this amp, but cannot take the place of it. This is well made, craftsmanship is top-notch, it is every bit of good I hoped for!
JTM Perfection In A Box
I saw Nashville ace, Tom Bukovac, getting some very fine vintage rock tones out of one of these and decided to give it a shot. I own all of the recent releases of the Studio series for my rehearsal / recording space. This is probably my favorite for most rock and soul applications. It cleans up really well but still has that nice top end sparkle. If you want a little crunch at low volumes, hit those strings just a bit harder and the preamp responds perfectly. If you want tube saturation without going deaf, the low wattage setting works great - with no compromise like some amps that lose all their detail when you shut off a valve or two.
It's an inspiring little amp to play. It's also a lot of fun to get near exact sound as Jimmy Page, Hendrix, Joe Perry, Gary Richrath, etc., My overdrives and fuzz pedals cook on this thing. A little is all you need. I use a Chase Bliss Automaton for my drives and put an Eventide H90 in the effects loop. Zero disappointment. Very satisfied. It's right up there with the Magnatones, Bensons and Two Rocks.
Great sound
I bought this amp because I love that early sound. Man this is a sweet amp.
Love this compact combo amp for its classic sounds
I recently acquired a JTM Studio Combo (ST20C) 3 months after getting the SV-20C. The cosmetics alone are worth the price of admission, but the real secret in this fire-breathing monster is the voicing. The JTM gets the Clapton "Woman Sound" in a tiny manageable package. The 12" Celestion Creamback is perfectly matched to the 6550 output tubes. Use this if you want to sound like vintage classic rock. Get the SV-20 if you want to emulate the harder, more aggressive rock of AC/DC, Free and Bad Company.
Update on repair
This is an update to my previous review (above?)on this amp. I took it to a local designated Marshall Factory Service outlet and they reported the following:
"Resistor R4 was unsoldered on one end. Most of the standing up components had inadequate solder. I could see light through the solder holes of the fuse clips. Several standing 1W resistors easily pulled off with a light tug. Went through the amp and resoldered most of the big components. The tube sockets were great and the small components and caps seem fine. Tubes tested good as new. Reassembled and tested."
So as suspected, the QA performed on this particular amplifier was inadequate. Amp is back in my "studio" and being played. Marshall needs to sharpen their game a bit.
Low Quality control?
I own this amp. Bought it from Sweetwater during the '23 Black Friday sale. Gotta a great price on it. And super deluxe shipping. I love the tone of this amp and have written reviews of it elsewhere.
But three months later, the amp is in the shop. Hopefully receiving warranty service because it has mysteriously died on me. Over the past two weeks, the volume (signal) has mysteriously faded to zero several times while playing it. This past weekend it died completely. Just as if someone had turned the volume knob to 0. Only no one had. There's no signal emanating from guitar to cable to input jack. Via multiple guitars and cables. The exposed end of the cable plug its completely quiet when touched. All 4 input jacks and either power mode (5/20w)
It's just as if a tube expired. But I don't think that's it....
So I'm anticipating that the entire circuit board is going to be swapped out for a new one. At least that's how I am told modern amplifiers are serviced.
Sweetwater has been great about this and has offered to investigate and repair but that involves me shipping the amp back to them. So I went local but everyone is so busy and backed up that it could be a few weeks before it even gets looked at.
Gotta have some concerns after all this about the quality of components Marshall is installing in their products.
