“It might not be the ‘Marshall sound’ your grandad loves, but for those who revere the harder-edged sound Marshall brought us in the ’90s, the Studio 900 hits the spot”: Marshall Studio 900 head and combo review

What is it?

Once thought of as a ‘modern Marshall amp’, you might like to sit down as you realise that the JCM 900 celebrates its 35th birthday in 2025. The successor to Marshall’s wildly popular JCM 800, which has graced albums by everyone and their Les Paul, the JCM 900, it could be argued was a slightly slower burn.

Marshall’s response to the thirst for guitar amp gain was ushered in from the hot-rodded sizzle of ’80s rock through to the advent of grunge, alternative rock, pop-punk, and it’s here that the JCM 900 found its audience – even the mop-haired Britpoppers got in on the action.

Now, as the JCM 900 reaches the age where it’s concerned with inflation, the UK icon has reissued it in a UK-made, dual-flavoured format that’s more reflective of the times: shrinking it down and adjusting the output power to a more manageable maximum of 20 watts and offered in both lunchbox-ish head and 1x12 combo platforms.

Outside of that, it’s the JCM 900 we’re used to. ”The Studio series is a tribute to our historical flagships, and as such they need to represent the heritage accordingly.” says Marshall Product Expert, Steve Smith.

Represent, they do. Of course, there were multiple versions of the 900, and this one is based on the 4100 (or rather, the 50-watt) 4500 - two channels with a shared three-band EQ and spring reverb. Marshall has even kept the same valve type and count, with a pair of ECC83s handling things on the way in, a third for the phase inversion between the preamp and power section, and a pair of 5881 (a close relative of the 6L6) in the power stage.

So, can the sometimes unfairly overlooked JCM find new fans as a smaller amp? Let’s get those valves glowing.

Specs

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Launch price: $1,499/£1,099/€1,499 (combo), $1,299 /£1,199/€1,299 (head)
Type: 20-watt tube head and combo amps
Origin: UK
Output: 20 watts (16 ohms), switchable to 5-watt, />1-watt
Channels: Two
Controls: Gain x2, Presence, Treble, Middle, Bass, Reverb x2, Channel Volume x2, FX loop level, High, Mid, Low power switch
Connectivity: Input, direct output, Recording Compensated output, effects send/return, 5x speaker outputs (4-16 Ohm), footswitch socket
Footswitch: Included (two-button: Channel/Reverb)
Weight: 39.4lbs/17.9kg (combo), 24.9lbs/11.3kg (head)
Dimensions: [HXWXD] Head: 245 x 510 x 240mm, Combo: 460 x 510 x 240mm
Contact: Marshall Amplification

Build quality

Build quality rating: ★★★★½

As with other Studio series models, the Studio 900 head and combo are both built in the UK. Marshall is clearly (and rightly) proud of this, “All the Studio series are made in the UK”, says Smith, “The idea being, we take legacy UK products and continue that story bringing it into a more usable form factor for the consumer… while maintaining the UK build quality.”

As a nod to this, the review amps come adorned with stickers stating who built and finished them – a nice touch that – similar to Gibson’s ‘baby photo’ or Seymour Duncan’s pickup initials gives the end user a sense of insight into their gear.

Build-wise, it’s classic Marshall as you’d hope or expect. The wood cabinetry is clad in a tough, textured covering that appears very difficult to scuff, with the added benefit that if you do, it’s unlikely to be quite so visible amongst the texture. The corners are all well-protected too, with solid ABS pieces shrouding any potential dings during load-ins.

Visually, the Marshall staples are in full flow too, with the black tolex outlined by neat white piping, and the classic gold-colored, brushed panel backing the controls. To the top of both the combo and head, there are sturdy rubber handles that are more than capable of supporting the weight (17.9kg for the combo, 11.3kg for the head). It all feels quality, with no obvious weak points that might reveal themselves in the future.

Usability

Usability rating: ★★★★★

I spend quite a lot of my time reviewing products that require a college course in button-pressing, menu-hopping and wireless networking. So, it’s nice to be confronted with a trusty tube amp once in a while.

The what-you-see-is-what-you-get nature of the Studio 900 – both the head and combo – means that using them is a doddle. And what you get is actually quite a lot too, with the front panel neatly laid out, linear fashion in one clean row.

The Studio 900 combo flows from (as you look at it) left to right, starting with the input jack, while the head’s chassis is mounted in the opposite orientation. First up are the gain controls for each channel, then the shared EQ section (Treble, Middle, Bass, Presence) and finally, the master sections which offer independent levels for Reverb and Volume per channel.

There’s more around the back, too, with four speaker outputs offering a comprehensive set of sockets for driving external cabs (as usual, clearly denoted with red jacks), a pair of direct outputs for sending your signal to a PA or recording interface - one is speaker-emulated and the other is not.

The effects loop features a level knob for greater control over the loop’s signal level, which here has been swapped from the original JCM 900’s trim pot to a full-size control. It’s much less fragile and doesn’t require a screwdriver to operate. Hurrah!

Finally there’s the footswitch socket and switchable Output Level toggle. This drops the amp’s output from its full 20-watts in the ‘High’ position to 10-watts in ‘Mid’ and less-than one-watt with ‘Low’ selected.

It’s all very straightforward to use: plug, play and tweak to get your sound. Independent EQ controls for each channel might be nice, but, the original didn’t have it, and it’s pretty standard for amps of this type to share its EQ between the two channels.

The only other absent feature I found myself pondering during my time with both amps is the ability to power-on without a speaker load connected. Marshall has kept the ‘Recording Compensated’ output of the original, and in 2025 where home studios are so ubiquitous that they’re just called ‘studios’, it would have been a useful feature. But, I’m being picky.

Sounds

Sounds rating: ★★★★½

Think of the classic ‘Marshall Sound’ and you’re probably imagining thick, creamy, trouser-flapping overdrive. But, you’d be forgiven for thinking that you’d plugged into an altogether different brand when first dialling-in the clean channel with the amp in High output mode. Not in a negative way, either - it’s bright, and full of headroom with the Gain control positioned between minimum and half-way. Make no mistake either, this thing is capable of being loud.

At this point, I’m met with a cutting, clear clean sound that will have a number of styles outside of Marshall’s ‘Rawk’ wheelhouse covered nicely, even with a Les Paul in the driving seat: from crispy funk and spiky ska-style skanks coming through like a blade - to the point where I needed to dial the EQ from its flat settings to remove a bit of the high end.

Cranking the master volume and adding some more gain in the preamp stage takes me more in the Marshall direction, with the front end warming-up slightly under a gain increase. It’s still definitely in the clean camp, but there’s a bit more grit to the sound overall.

This continues right up to the first channel’s maximum gain setting, where things begin to enter the grittier end of clean rhythm playing for indie and blues, and from here on out, it’s a game of Chicken between how far I’m willing to push the output volume into power stage overdrive, and how fast my neighbours can remember the number for the emergency services.

Switching to Channel B is where I find the signature distortion character of the JCM 900. It’s important that this isn’t overstated, though, because while there’s a lot of gain on tap, by modern standards it’s not really what I’d call ‘saturated’.

You can get plenty of sizzle going, and between the Gain control and EQ, it’ll cover a lot of ground. At the lower end, Channel B serves up punky overdrive with plenty of punch from the mids (especially when boosted). Adding more gain takes me into ’90s alternative territory, while cranking the gain up and dipping the mids slightly tightens things up for that classic scooped metal tone.

I’ve mentioned volume, and this amp is, after all, part of the Studio series. So, the variable power switch on the back is a great addition if you’re likely to be using this as a recording amp at home as well as taking it out to play live.

It’s not a miracle worker, though - if you’ve ever played through the likes of Marshall’s DSL1 or the Blackstar HT-1, you’ll understand that one-watt in the world of tubes doesn’t necessarily mean ‘quiet’. But it does mean ‘quieter’.

As I flick the switch to the ‘Low’ setting, there’s a noticeable drop in volume, accompanied by a bit more compression and a spongier feel that’s quite forgiving, allowing you to dig in while taming some of the spike on the clean channel. In the lower power modes, it’s possible to use the amp at quieter volumes while still getting some sense that you’re exciting those output tubes to generate tone rather than all-preamp gain.

This review is of two identical products presented in different formats, and you might have noticed that so far my experience between the two has been exactly that. But, there is one point that is worth noting.

The Studio 900 combo comes equipped with a Celestion V12 - the same speaker that has populated thousands of Marshall cabs as part of a quartet. Meanwhile, Marshall also supplied 1x12 and 2x12, Celestion V-Type-loaded cabinets from its existing Studio Classic series for me to try the amps through.

Now, on paper, these speakers are quite similar - the G12-T is rated at 75 watts at 16 ohms, while the V-Type is 70 watts. Both feature ceramic magnets and a similar sensitivity rating and frequency curve. However, during my time playing through both the combo and head/cabs, I noticed a distinct difference between the two speakers.

Where the combo is light on the low end, the Studio Series cabinets restore the thump that you might be looking for from a hard-edged rock amp (even if it is lower-watt). This is to be expected from the 2x12 – there are twice as many speakers moving twice as much air, after all – but both the head and combo version of the Studio 900 played through the Studio Classic 1x12 yielded an additional layer of bass.

If your intended use for this is in the live environment, that will make a difference. However, the less bassy response from the combo may not be a problem if you plan on using this at home, particularly for recording, as that low end weight could very likely end up being mixed-out with high-pass filtering on a recording. But, you can’t adjust what isn’t there, so, if you already own a cab, or would prefer the larger bass response, it’s worth considering.

Verdict

There’s a subliminal expectation with amps that smaller must mean cheaper. Indeed, this is fuelled further by the abundance of low-watt lunchbox-style heads on the market, produced in the far east.

Marshall produces the full-fat JCM 900 4100 head as part of its Vintage Reissue series. In the US, the street price difference between the Reissue and Studio heads is significant - around 35 percent, or $700 in cash.

For our UK readers, the margin is narrowed somewhat, with a list price difference of just £200, and a street price of around half of that between the Vintage Reissue and Studio heads. While Marshall’s dedication to UK-made product is admirable, I can’t help but think that many people would like to see the Studio series come in at a lower price point, even if that means production taking place elsewhere.

The combo and head versions are both great-sounding, with your choice of speaker being the overriding variable. Of course, you can connect the combo to an additional cab such as the Studio Classic 1x12 for a 2x12 setup. Similarly, the head, coupled with the V-Type-loaded cabs delivers all the meat, crunch and grit you’d hope for.

Both offer a surprise element of versatility thanks to Channel A’s headroom and ability to create a squeaky-clean tone for when you need it. As I mentioned previously, it would be great to be able to operate both of these amps without a speaker connected, or at least with the speaker output muted when hooking up to the ‘Recording Compensated’ output for silent use when needed.

Overall, I think the Studio 900 head makes the most sense of the two in terms of being adaptable to different applications. If you’re looking for a self-contained option, that’s obviously where the combo comes in.

It’s fair to say that the iconic brand’s output has been sporadic at times over the last decade, but it appears to have hit a stride in the last 18 months with the reissue of its ’80s pedals, the introduction of its new amp-in-a-box pedals, and the Modified series alongside the Studio 900 amps.

Guitar World verdict: Here, Marshall has successfully taken another of its classic designs and refreshed the format for a time when high-output heads and large-format cabs are less convenient. It might not be the ‘Marshall sound’ your grandad loves, but for those who revere the harder-edged sound Marshall brought us in the ’90s, the Studio 900 hits the spot.

Also try

Hands-on videos

Marshall Amplification

Studio 900 Head & Combo Official Demonstration | Studio Series | Marshall - YouTube

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Guitar Center

NEW Marshall Studio 900 20W Amp Head | NAMM 2025 - YouTube

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Fair Deal Music

All New Marshall JCM900 Studio - Is It The 20 Watt Amp You Need? - YouTube

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