Built from Tweed for Extra Speed
Though rightly recognized as one of the most significant amps of the 1960s, the JTM45 can confound casual Marshall enthusiasts with modern, high-gain leanings. It effectively mirrored the Fender 5F6A tweed Bassman circuit. But small differences between the amps (as well as bigger ones, like the Marshall’s Celestion speakers) added up to a unique and powerful voice perfectly suited for the emerging British blues-rock language.
To reduce the 30 to 40 watts produced by a JTM45 (depending on spec and era) to 20 watts while using the same 5881 power tubes the JTM45 was born with, Marshall uses a cathode-biased output stage and hits the tubes with lower voltages than big Marshalls run on. The circuit also enables the ST20C, and its sibling the ST20H head, to run even quieter via a 5-watt mode. It comes with contemporary niceties like an effects loop with bypass switch, a DI output, and speaker outs for 4-ohm, 8-ohm, and 16-ohm loads. But the ST20C is still a very old-school, all-tube creation at heart, using three ECC83 (Brit-speak for 12AX7) preamp and phase-inverter tubes, just like its predecessors.
Coffin It Up
Like the Bassman-inspired JTM45, the ST20C is what Marshall calls a two-voice amp, with shared EQ and two inputs per voice. Marshall’s numbering scheme for the inputs can be a little confusing to the uninitiated (they read “2” and “1” from left to right), but the top two inputs are for the high-output voice, the two below are for the low power voice. In each voice, input 2, aka the normal input, is the warmer and rounder-sounding of the two. Input 1, or the high treble input, brighter and snarlier. Each has its own loudness control, but they share treble, middle, and bass controls, as well as a presence knob that further tweaks high-end response at the output stage. The two voices can also be jumpered to access blends of input 2’s warmth and input 1’s brightness.
“Newbies might be surprised to hear how much the ST20C deviates from a modern definition of the Marshall sound.”
In addition to the vintage-evocative control panel, Marshall went all-out on the early JTM-era cosmetics for the ST20C, and I think it looks fantastic. The black levant covering is complemented by gold string and piping, fawn fret cloth for the grille, and an art deco “coffin” logo with red enamel “Marshall” text. Construction of the 19.7" x 18.1" x 10.4" birch-ply cabinet feels robust, and with the 16-ohm Celestion G12M Creamback speaker, it still weighs just around 39 pounds.
The Studio Series amps aren’t among Marshall’s handwired offerings, so the circuit inside is PCB. Nevertheless, it looks sturdy and well-built. The use of relatively low voltages in the output stage means the 5881 tubes should last longer than they would in a higher-wattage, higher-voltage amp. But if you do need to replace them, the cathode-biased configuration means you just pop in a new pair of 5881s and go—there’s no bias adjustment necessary.
Breaking in, Breaking Through
I checked out the ST20C with a 1959 Les Paul Reissue to see how it handled the classic Bluesbreaker formula, as well as a 1966 Fender Telecaster. With each guitar, it delivered a wide and expressive range of tones that are very much in keeping with the original’s performance. Newbies might be surprised to hear how much the ST20C deviates from a modern definition of the Marshall sound. But it is surprisingly versatile for that reason. And you can make the case that the ST20C tone palette works for a greater range of playing styles and genres than the average blaring stack.
The core tone is characterized by a thick, round midrange; silky, clear highs that aren’t piercing; and low-end tones that are full, round, and a little loose when you push it. The amp also works beautifully with overdrive pedals. A Tube Screamer sounded great, and a Marshall-style Friedman Small Box overdrive effectively brought out the ST20C’s plexi side. The effects loop works perfectly for time-based and modulation effects. Meanwhile, the 5-watt power setting rips without any significant tone loss.
Many players more familiar with the plexi and JCM800 Marshalls will be surprised by, well, how Fender-y the ST20C can sound. Obviously, the tweed Bassman-derived blueprint accounts for some of that. But if you’ve ever turned up an early-’60s, brown-panel Fender Deluxe and thought, “wow, that sounds like a mini Marshall!” … you’ll recognize that hybrid sound in many of the ST20C’s sweet spots, too. Crank it up and it’s raw, throaty, and singing like an early Marshall should be. Play it at the edge of breakup and it evokes more American-style tones. The ST20C’s ability to span these sounds and assert its own personality makes it a fun, flexible and inspirational piece of gear.
The Verdict
The JTM ST20C is an awesome addition to Marshall’s popular Studio Series and it’s cool to hear the tonalities of the company’s first amplifier rendered in such compact, practical form. Some buyers might find the near-$2K price tag high for a PCB-based, 20-watt amp. But when you consider the wide range of genres and styles this compact U.K.-built combo covers, and how assertive and primed to conquer it can sound and feel, it starts to sound like money well spent.
Marshall Studio JTM ST20C Demo | First Look
Those players will be happy to hear that much of the Z-28’s basic architecture remains intact in the Mk. II. Crucially, the original Z-28’s EF86 pentode preamp tube carries over to the front end of the new design. It was a key to that amp’s personality and combination of high headroom, high gain, and thick-yet-clear voicing that hooked many Z-28 followers. But the platform’s dual-6V6 output stage has now been upgraded to a pair of larger 5881 output tubes in cathode-bias, generating 35 watts of power. Additionally, a new master volume control helps rein in the output, so there’s plenty of the good stuff available at less overall volume than the Mk I.
Red Menace
The Mk. II is more than an updated circuit. Dr. Z houses the Z-28 Mk. II 1x12" combo in an updated cabinet, too. This time out, the Z-28 lives in a cab Dr. Z introduced with the Joe Walsh Signature Z-Master. But where that amp was configured with three 10" speakers, the Mk. II features a single-12" baffle and a Celestion G12M Creamback. The cabinet is built from thin-walled ply and measures 22" x 21.5" x 10.9". The dimensions and construction help keep this mid-powered combo’s weight down to a very reasonable 38 pounds. The Mk. II also brings Dr. Z’s popular red-Tolex livery back to the fold. It’s exclusive to the Z-28 Mk. II combo. (A Z-28 Mk. II head is also available, in black only.)
Control interface-wise, the Z-28 Mk. II is just as austere as the original, with the exception of the master volume. Apart from the single input, there’s a volume knob and independent treble and bass controls in the EQ stage, which conceals tone-sculpting capabilities much more powerful than you would expect. Utilizing Dr. Z’s version of a Baxandall tone circuit, these controls offer fairly traditional high and low frequency sculpting from the fully counterclockwise position to noon. Past noon, though, the frequency boost comes with a bump in preamp gain. The result is that there are many more voices and gain gradations available than the deceptively simple 3-knob preamp implies. What’s more, the post-phase-inverter master volume is removed from the circuit when it’s maxed if you want to run the MK. II wide open.
The Z-28 Mk. II uses a 12AX7 in the phase inverter and has a 5AR4 tube rectifier. Cathode biasing of the output stage means you just pop in new replacement tubes when the time comes—there’s no need to re-bias, which is very convenient. Although the 5881s can be substituted with more common 6L6GCs—also with no bias adjustment—the Doc tells us: “I like the 5881s better than the 6L6s I tried. The 5881s seem, to my ear, to be closer sonically to the 6V6, which is what I was trying to achieve in the Mk. II.” Otherwise, a look inside the chassis reveals the same kind of high-quality, handwired circuit that we have come to expect from this Cleveland-based maker.
American Muscle
The Mk. II is an able successor to the original, and then some. I should confess here that I was a fan of the dual-6V6 Z-28 from the time of its release, and I chatted with Zaite about that amp’s merits on many occasions. In my estimation, the Mk. II simply brings more of the good stuff to the table, without leaving out any of the stuff that made the Z-28 great.
A big part of this amp’s magic is in the character of the EF86 pentode preamp tube, which is thicker, lusher, and more full-frequencied than a 12AX7 in most circuits. This tube’s capacity to be pushed hard without folding into self-distorted fizz means the signal is bold, clear, and articulate before it hits the next stages of the amp. As a result, the overall voicing and character is classic ’60s-era American, but it’s complex—blending late tweed, early ’60s brown-panel, and mid-’60s black-panel tonalities with a little extra girth and muscle that tends toward Marshall-like—especially when pushed to overdrive.
As such, the Mk. II makes a great clean-to-mean template without any help from pedals. And the versatile tone controls extend the broad range of voicings considerably. While It’s probably not the best shred platform, the Mk. II’s ability to span roots and blues colors, rowdy classic and garage-rock sounds, and even jazz tones is impressive. The preamp’s copious headroom and robust performance also makes it an outstanding platform for drive pedals—without exhibiting any of the sterility that the handle “pedal platform” often implies. The Z-28 Mk. II lapped up the output from a TS10 Tube Screamer, Tsakalis Six, Wampler Tumnus Deluxe, and JHS Angry Charlie with ease and relish. The master volume works great, too, meaning you can explore the Mk. II’s voices at much lower-volume settings than the Mk. I could handle and dig every minute of it.
The Verdict
The Z-28 Mk. II is a clever reimagining of a well-loved original Dr. Z design. And it quite simply delivers more of everything that won fans for the already impressive Mk. I. Simultaneously stout, thick and articulate, with beautiful cleans and excellent overdriven tones, it’s also a great drive-pedal platform, and a dynamic and expressive amp by any measure.
Dr. Z Z-28 MK II 1 x 12-inch 35-watt Tube Combo Amp
- EF86 preamp delivers a high-fidelity sound with outstanding dimensionality and dynamic response
- Delivers everything from crystal-clear cleans to muscular overdrive
- Clean tones makes a superb pedal platform; effects sound like they're built right into the amp
Simple Complexity
The Catalyst has plenty of bells and whistles. On the surface, though, it looks a lot like a simple, conventional 2-channel amp. There are knobs for boost, gain, bass, mid, treble, presence, channel volume, effect, reverb, and master volume. There’s also a knob that lets you choose from six original amp models: clean, boutique, chime, crunch, dynamic, and hi gain. Mini buttons let you save and choose between two channel presets or engage manual mode, where what you see is what you get. Other mini buttons allow you to engage boost, tap tempo, and select effects and a tuner. On the back panel is an output power knob that lets you choose from mute, ½ watt, 50 watts, and 100 watts. There’s also a USB jack, a DI out, and an effects loop.
Six Amps in One
There’s not enough space in this review to cover all the amp models in depth. And I suspect that for many players even just a few used through the full range of their clean and dirty variations will be everything they ever need. Still, the Catalyst’s abilities and potential—especially relative to its price—will excite any potential user.
I started my own experiments with the boutique voicing at the ½-watt output setting. Predictably, there’s not a lot of output in this mode, though it’s a lot of fun as a practice amp. At the 50-watt output setting, though, I could hear and feel the amp in a more complete way. There was headroom to spare and it’s impressively dynamic and responsive to picking nuance. And it was surprisingly easy to get SRV-style bite out of otherwise clean, blues-tinged phrases—again, very impressive. The useful boost knob lets you dial in extra kick, and, thoughtfully, each amp model has a specifically tailored boost voicing. In boutique mode higher boost settings added a lot more gain to the amp model’s cleanish sound, and the saturation sounded and felt organic.
The chime model, loosely inspired by a Vox amp, is warmer and thicker than the boutique model in cleaner settings. But when I engaged the boost (with the knob at noon) and set the gain knob around 11 o’clock, the amp positively screamed—generating an aggressive and at times piercing sound that would reward a player with a commanding approach like Eric Gales or a 1960s-influenced guitarist who loves the potency of single-note lines.
The high-gain model, meanwhile, is a fire-breathing beast. With the gain at 11 o’clock, there is plenty of bottom end, and the sensation of the amp moving air becomes more apparent. Engaging the boost softened the attack slightly, which made soloing more liquid. But there wasn’t much of a difference through the range of the boost knob from noon to max. The amp model is pretty saturated to begin with.
There was headroom to spare and it’s impressively dynamic and responsive to picking nuances.
No Jumping Through Hoops Running Loops
Using the clean model, I ran my Yamaha UD Stomp delay through the effects loop. The results were dimensional and often sublime. The power-amp-in feature lets you plug in a pedalboard and play it directly into the Catalyst 100’s power amp. I used another setup, with a Mesa/Boogie V-Twin preamp pedal, directly through the Catalyst’s power amp and it sounded phenomenal. And even though the preamp is bypassed in this mode, the boost function is still active. Set at 10 o’clock, it added a nice final touch to the Mesa/Boogie preamp’s clean channel, making it sound discernibly richer. In my humble opinion, just the power amp and speaker cabinet alone are worth the $399 price.
Though Line 6’s acclaimed HX technology is embedded in the Catalyst, the company did a good job of keeping options easy to manage and navigate. There isn’t an endless buffet of effects, as you might expect. There’s a standalone reverb, and apart from that you can only use one additional effect simultaneously, unless you bring your pedalboard to the party.
In total there are 18 effects, grouped into three categories: delay, modulation, and pitch/filter—each with a corresponding LED in green, blue, or purple, respectively. If you’ve used Line 6 products before, many of these excellent effects (and the color coding) will be familiar. There’s the fabulous dynamic “ducking” delay, some modulation models based on iconic pedals like the MXR Phase 90 and others, and some classic Line 6 pitch/filter effects like growler synth and synth strings. If you do want to use more effects simultaneously, the effects loop is an excellent way to patch in external effects.
The USB hookup, by the way, enables connection to a computer so you can use Line 6’s editing software, which allows you to dive deep into tone editing or just fine tune a few things. I imagine that, in reality, most users will just figure out how to get a couple of core sounds directly from the amp, save them, and just go with that. But it’s always great to have options, and if you’re someone that actually maximizes the capabilities of modelers and editors, you’ll have a field day with the app.
The Verdict
For any guitarist looking for an all-in-one, plug-and-play setup for practice sessions, live shows, and recording (you can record directly using both USB and the built-in DI with cab simulation), the Catalyst, at $399, is pretty tough to beat. It’s got more features than many players will need, but what will count for most of the target audience is how much you can accomplish without diving too deep. And though the price might suggest otherwise, Catalyst isn’t just for beginners or intermediate players. Any professional guitarist that’s tired of dealing with tube related maintenance and expenses will be happy with many of the sounds here.
These amps have never been cheap. But the new EVH 5150 Iconic Series models offer a much more affordable take on 5150 designs and are offered in two versions: a 40W 1x12 combo that retails for a very reasonable $899 and an 80W head version at $999. For this review, we look at the 2-channel combo.
High-Calorie Combo Platter
The 5150 Iconic Combo is powered by two 6L6 power tubes, two ECC83 preamp tubes, and a specially designed 40-watt Celestion speaker, all of which are encased in a closed-back MDF cabinet for tighter, heavier bass response. Closed-back combos are slightly unusual as they are costlier to manufacture and tube cooling can be a concern. Most dedicated EVH tone chasers will probably be happy for the audible effects of the closed-back configuration, though.
The combo has a sparse, utilitarian vibe. Apart from a 5150 logo on the top left corner of the cabinet and an EVH logo affixed to the bottom right corner of the grille, there’s little to distinguish it. The controls are hidden away on the top panel. Here you’ll find gain and volume knobs for each channel, and shared controls for EQ (low, mid, high), boost, reverb, resonance, and presence. There’s also a noise gate control exclusively for channel 2. There are three mini buttons: one for channel switching and the other two for the additional presets for each of the channels.
The rear panel is home to a XLR output (with speaker emulation), a power amp mute switch, a preamp out jack, a power level switch (which lets you choose between 40W or 10W), and an effects loop. The cool thing about this loop is that you can use the return jack to bypass the preamp while the boost, reverb, resonance, and power level remain functional.
A Ton of Gain Unchained
While the 5150 Iconic is a 2-channel amp, each channel has its own switchable low-/high-gain mode, effectively giving you four different gain profiles. Channel 1 has a push button for selecting between clean and overdrive. The channel 2 mini-button, meanwhile, engages the ultra-hot “burn” voicing.
The overdrive preset of channel 1 is essentially a crunch channel, sort of like the blue channel of the 5150 III, but with slightly more gain. Even with the gain at 2, the overdrive preset is pretty distorted. Bumping the gain to just 4.5 yields tones closer to distortion than overdrive.
Channel 1’s overdrive mode ranges deep into high-gain realms and could easily be used as a “lead” channel.
Channel 1’s overdrive mode ranges deep into high-gain realms and could easily be used as a “lead” channel. Channel 2, however, is comparatively hellacious. With gain at just 2 you’ll get output roughly equivalent to channel 1’s overdrive channel with the gain at 8. With channel 2’s gain up to 7, I was well into extreme modern metal territory. But that’s just the tip of the iceberg! Channel 2’s burn mode adds even more heat and saturation, yielding ridiculous amounts of sustain. Single notes seemed to last forever, even without finger vibrato. At times it felt like an EBow at work.
With this much over-the-top gain available, it was a smart move for EVH to include a noise gate on the 5150 Iconic. The gate is helpful, but it has its limits. Even with the gate threshold at maximum, a fair bit of hum and amp noise persists at the most beastly levels.
The Best of Both Channels
If there were a way to footswitch between channel 1’s clean and overdrive sounds, the 5150 Iconic would essentially become a 3-channel amp, with clean, crunch, and lead sounds. But that would likely make the Iconic much more expensive.
In lieu of a footswitchable third channel, though, the boost function, which is footswitchable and adds up to 10 dB of volume, is one way to MacGyver a faux 3-channel setup. I got a pretty workable template using these three settings:
- Channel 1 with gain on 2 and overdrive preset selected. Guitar volume lower for a cleanish sound.
- A boosted version of that cleanish sound, with boost on 8 and guitar volume at maximum for a crunch sound.
- Channel 2 with gain high for a lead sound.
If only there were a way to get a footswitchable setup with four sounds to include the burn preset!
The Verdict
James Brown, the legendary amp designer who worked closely with Eddie Van Halen to create the original Peavey 5150 amp, was recruited by EVH in 2019 to become a principal analog engineer. He was tasked with masterminding the 5150 Iconic series. And it’s safe to say Brown succeeded.
The resulting 5150 Iconic Series 40W 1x12 is a unique amp. It can easily do the Van Halen thing. But it’s also insanely versatile and capable of sounds from clean to ultra-high gain to the most extreme molten metal. It’s also just a great all-around amp. And it’s easy to imagine the 5150 Iconic becoming ubiquitous in the manner of a Fender Hot Rod Deluxe for the heavy-music set.
EVH 5150 Iconic Series Combo Demo | First Look
