Initially, the extra inputs/channels found on a typical amp from the ’50s or ’60s were intended for other instruments or microphones. By the mid 1970s, however, clever designers such as Hartley Peavey and Mesa/Boogie founder Randall Smith had figured out that there was more to be gained (no pun intended) by using multiple channels to create different levels of overdrive. The birth of the channel-switching tube amp was fully realized with the introduction of the Mesa/Boogie Mark IIC—a two-channel, high-gain marvel that allowed a player to easily preset their rhythm and lead tones and then select between them via footswitch. The Mark II series and subsequent Mark IV models would inspire a whole new generation of amps with multiple channels, and some 30 years hence, the common format for amps in the 50- to 100-watt class is two to four channels with independent gain, volume and EQ controls for each. This setup affords the player a great deal of control over clean and distorted sounds, and with such features as channel assignable effects loops and MIDI implementation, the sky is now the limit for those who need to call on lots of sounds during a show.
The amplifiers reviewed here represent some of the newest high-powered, multi-channel production models around. All clock in at 100 watts and feature three or four footswitchable channels, assignable effects loops, and MIDI control of key switching functions (though not of the actual control settings). We tested these amps though their supplied 4x12 cabinets, and used a variety of guitars during the process (including Gibson Les Pauls, Fender Strats, a Hamer Talladega, and the new PRS DGT and Mira models.
The most advanced rock/metal amplifier ever to roll out of Carvin’s Southern California factory, the V3 (a combo version called the V3212 is also available) immediately grabs you with its 23 knurled, chrome-plated knobs—which appear slightly recessed into the black cutouts created by the slotted gray faceplate. The blue jeweled pilot light and trio of mini-toggle channel switches look sweet, and about the only thing that doesn’t entirely work for me are the fine reference lines that are etched into the face of each knob—keep a flashlight handy if you plan on dialing-in precise settings on a dark stage. The three channels feature independent controls for gain, volume, and EQ, and can also be selected by an optional footswitch or MIDI. Each channel has a 3-position Drive Mode switch that changes the gain structure. For Channel 1 and 2 the Drive Mode choices are Intense, Classic, and Thick; for channel 3 (the “clean” channel), the selections are Bright, Classic, and Soak. Each channel is also equipped with an EQX switch that broadens the frequency range for the Bass and Treble controls (as well as the Mid control on channel 3).
At the upper left side of the panel are Master, Boost, Bright, Mid Cut, and Deep controls, along with a pair of Smart Loops switches that can be used to recall series or parallel loop settings for each channel. Up to 100 combinations of channel selection, Loop 1 and Loop 2 on/off, and Boost on/off can be programmed via MIDI.
Among the most significant rear panel features are the 100-watt/50-watt switch, the Bias selector (which makes it easy to change from EL34 to 6L6/5881 tubes), and a Tail switch for each loop. When activated, the Tail function allows delay and reverb tails to decay naturally rather than being abruptly cut off when the loop is switched off.
Inside the V3’s folded-steel chassis we find the circuitry arranged on five PC boards, which are interlinked with ribbon cables. All of the components, aside from the power and standby switches, are board mounted. The ceramic power-tube sockets are stoutly anchored to both the board and the chassis, and the pots have metal shafts for added strength. Less inspiring is the way the ribbon cables are haphazardly bundled together, and the method of twisting some of the leads in mid span to shorten their length. Also, the use of fastener-type screws to secure the chassis doesn’t inspire the confidence you get from heavy-duty machine bolts.
Though designed to produce the high-gain, heavy-bottom tones that metal players crave, the V3 is a highly flexible amp that can work well for lots of different styles. Channels 1 and 2 seem to be identical in terms of voicing and gain, however, between the various Drive Mode settings, the tone and gain controls, and the EQX, you can configure them to sound as different as night and day. Some of the best distortion tones were derived on channel 2 (though it could have just as easily been channel 1) with the Drive about one-third up and using the Thick setting with the Mids at zero. With the Drive control all the way up, the V3 delivers endless sustain—even at very low volumes. The tones are quite bottom heavy, however, and with some guitars it proved best to keep the Bass control at zero, and just use the Deep knob to dial in the lows. This produced a clearer sound overall—one that even worked better with single-coil guitars. The highs could also get pretty intense with some guitars—including models with humbuckers—and it seemed better to keep the Presence controls at zero and just use the Bright and Treble knobs to tweak the top end. Channel 3 produces a good range of clean tones with excellent headroom, but you can get a fair amount of grind here when you max the Drive control—especially with the Soak function active.
The V3 is extremely loud, and while the half-power switch does help make this amp more civil in smaller rooms, it’s still a raging beast when you crank up the masters and let it rip. As with most tube amplifiers, the V3 benefits from the distortion contributions of the power tubes. All of the tones sound richer and have better dynamic feel when you turn up, and when you are in situations where more volume is needed to make a solo stand out, the variable Boost function will push the output by up to 9dB. Unfortunately you can’t access this function unless you buy an optional footswitch or MIDI controller. The V3 offers a lot of value by providing most of the key features of the higher-priced amps at a price that is hundreds of dollars less than many of its competitors. Its over-achiever bass response may not be to everyone’s taste, but for an American-made amp with multiple channels and MIDI, it’s a solid deal.
Engl Invader 100
The German-made Invader looks as intimidating as its name suggests. With those five black metal bars that serve as a grille, the chrome-plated front panel with its 24 knobs, and LEDs mounted behind the power tubes to cast an eerie blue glow inside when you power up, it’s a feast for the eyes. The black pointer knobs provide fully independent control of gain, volume, and EQ for all channels. Selections are made by pressing one of the small switches next to each channel (an LED indicates the selected channel), or by optional footswitch or MIDI. On the far left side of the front panel are the Bright and Hi Gain switches—both of which also have adjacent LEDs to indicate their status. Other features include Presence and Depth Punch controls, Master A and B controls, an effects loop selection button, a Master A/B button, and a Write/Copy button for MIDI programming. The Invader can store up to 128 MIDI program commands—one of which could be an “amp mute” function that is only accessible via MIDI or the optional Z-9 foot controller (a front panel LED indicates when the amp is in mute mode). A power stage monitoring system also prevents the power amp from being activated if speakers are not connected to the amplifier. The LED above the Write/Copy button serves as an indicator of a number of conditions, including memory error, no speaker connected, and power tube problems. The only rub is that you have to learn the flashing codes that the LED blinks out in order to know what the actual problem is. Notable on the rear panel is a Threshold Level knob that lets you adjust the sensitivity at which the noise gate kicks in to suppress unwanted hiss and buzz. You can activate the noise gate on channels 2, 3, and 4 with a front-panel button.
The spot-welded steel chassis contains eight PC boards that grip nearly all of the components, save for the transformers, a large electrolytic capacitor, and the power, standby, and ground switches. You can’t see most of the smaller components, though, as the boards are mounted topside down. Short wire runs keep the interior neat, and most of the ribbon cables are tucked out of the way. The tube sockets are all ceramic, and those for the power tubes are mounted to the board and chassis for additional strength. The construction looks robust overall, though the pots all have plastic shafts, which makes them more vulnerable to being sheared off. [Engl points out that it’s preferable to have the pots shear off rather than damage the board and chassis.]
As the Invader’s 4x12 cabinet was suffering from some blown speakers, most of our listening tests were conducted using the Marshall 1960A cabinet that came with the JVM 410H. How this impacted the overall results is hard to gauge, but through it, the Invader 100’s clean channel sounded deep and dimensional, offering a blend of sparkle and complexity that was so satisfying I didn’t lament the absence of onboard reverb. The controls are voiced beautifully, and the amount of headroom is astonishing. You can swing Gain 1 up past the halfway mark to bring on some grind (or just press the Hi Gain switch, which slathers on a turbo-like gain boost). The Invader’s channels are all voiced a little differently, and some of the overdrive tones that can be obtained from Channel 1 may work perfectly for some styles. Channel 2 is great for moderate distortion tones, and it sounds equally cool with humbuckers or single-coils. Wick up the Gain 2 control and the distortion comes on forcefully, making it easy to obtain flutey, sustaining lead tones at any volume. The harmonic richness is impressive as the Invader starts working its overdrive magic—juicy distortion is this amp’s forte, and the note definition is unreal. The Invader is also very dynamic, and you can roll back your guitar’s volume knob to obtain cleaner tones on any channel—even when using ridiculous amounts of overdrive. Jump over to channel 3 and the voicing is optimized for the huge amount of saturation available from the Gain 3 control. The slightly skinnier vibe in this mode practically begs you to go straight for the most saturated tones, and here too, the note definition is amazing. Channel 4 offers the maximum level of saturation the Invader can deliver—which, to say the least, is extreme when you add the Hi Gain function. Metal players will especially dig the depth and ferocity of these tones, which still retain plenty of stringy slice, even with humbuckers. The Invader’s EQ always gives you what you need with just subtle twists of the controls, and I never had to resort to extreme settings to dial in happening overdrive tones with our test guitars.
Capable of myriad combinations of distortion and output levels that can be configured on the optional Engl Z9 board or your choice of MIDI floorboard, the Invader 100 scores for its aggressiveness and richly detailed sounds. It certainly has all the features one could ever want in a four-channel amp, making it a cool choice for hard rock and metal players who want the extra level of control afforded by MIDI.
Designed and built at Marshall’s factory in Milton Keynes, England, the JVM 410H is a four-channel monster that offers three switchable modes per channel—effectively giving you 12 different gain options. The front-panel buttons next to each channel are dual purpose in that they not only activate the Clean, Crunch, OD1, and OD2 channels, but by continuing to press them, they also toggle you though the three gain modes—each of which is indicated by a green/orange/red indicator built into the button. And when you switch to a different channel, the JVM’s system remembers whatever mode you’d selected on the previous channel.
Despite having enough knobs to rival a jetliner’s cockpit, the JVM’s control layout is logical and easy to use. Along with dedicated Gain, Volume, EQ and Reverb controls (with bypass switch) for each channel, there are two Master Volume knobs (with selector button), as well as output-stage Resonance and Presence controls. The “serial/parallel” effects loop has a front-panel bypass button, and, lastly, there’s a Footswitch/MIDI Program button that’s used to program both the included six-button footswitch, and the MIDI control functions—which can include up to 128 combinations of channel, FX, reverb, and master A/B settings.
The JVM’s footswitch is a particularly elegant design, as it not only gives you total control of all of the amp’s switchable functions, but also allows you to determine how you want it to operate. For example, in “preset store” mode you can store any current channel/master/FX combination by simply holding down any footswitch button you desire for three seconds. Conversely, in “switch store” mode you can configure any of the footswitches to mimic any of the front-panel switches (though not the MIDI program switch). The truly amazing thing about this all-powerful footswitch is that it uses a standard guitar cable to connect to the amp, and it doesn’t have to be a shielded cable, either. Now that’s smart!
The spot-welded steel chassis houses neat circuitry that is laid out on only two PC boards—one for the front panel functions and another for the main circuit components and the rear-panel jacks and switches. You get full access to the caps, resistors, relays, and other items, and the only weird thing is how some of the pots (all of which have plastic shafts) are able to slightly flex the board when you rock them up and down. [Marshall states: The play in the pots is due to construction reasons. First, it is complicated and difficult to perfectly align 28 pots mounted on a PCB into a perfectly flat metal box. Second, if the pots had individual nuts they would put permanent strain on the PCB when bolted to the chassis. The pots are soldered to the
double-sided PCB at six points, including two strain-relief pads, and they also each have a metal collar. These pots are manufactured by a very reputable maker. With the construction used in the JVM 410H, there will only be strain on the PCB if the user applies way too much force.]
The JVM has so many gain options it can be kind of mind-boggling trying to figure out what to do with them all. The Clean channel provides a nice range of crisp tones with excellent headroom and a predictable amount of breakup as you move the Gain knob past halfway. Nudging into the Orange mode, the grit factor goes up, and the overall sound assumes a tougher demeanor that’s great for blues. Going to Red mode, the tones become much more distorted and sustaining, and suddenly you realize that you could easily cut your blues gig using just the Clean channel and its accompanying modes. These sounds are not particularly Marshall-like, however, and that’s because the Clean channel’s tone circuit (or stack) is configured ahead of the main gain stage (as opposed to after the main gain stage, as is the case with most Marshalls). The reverb sounds good on these clean-to-moderately-overdriven sounds. There’s a lack of sproinginess to it that quickly makes you appreciate its digital origin (ditto for when you rock the head back and forth and don’t hear springs crashing), but it is at least configured so that the reverb tails are not cut off when you switch channels.
The Crunch channel sounds more plexi-Marshall like, which is partly due to having the tone stack configured after the main gain stage (same with the OD1 and OD2 channels).
A little more gain is added in the Green mode than you’d get with an old (or reissue) JTM-45/1959 model Marshall, but that dynamic, punchy grind is apparent as you turn up—there’s just more of it on tap. Switching into Orange mode yields a gain range similar to that of a JCM 800, and this is where the tones start to really happen for hard rock and classic metal. More gain is poured on in the Red mode, but the JCM 800-style voicing remains intact. You can get serious amounts of ballsy distortion here, yet the dynamics are such that the tones still clean up well when you lower your guitar volume. From here, the fundamental timbres of the JVM don’t change much, but with extra gain stages being brought on line courtesy of the OD1’s Green, Orange, and Red modes, the amounts of distortion and sustain increase dramatically. This is where you go for your scorching lead sounds, and even with single-coils, there’s more than enough gain to sustain notes ad infinitum. The OD2 channel adds even more gain, but more importantly, the Middle control’s frequency range is shifted downward by about 150Hz to voice it more suitably for scooped-mid metal tones—very wicked metal tones I might add, especially when you can open up the masters and let those EL34s bring their gristly muscle to the brew. You’ll need a big stage to do so, however, as the JVM gets extremely loud when its EL34s start working. On the flipside, by putting the amp on standby you can safely disconnect the speakers and use the line out for silent recording.
All considered, the JVM is an amazing amp and a very fairly priced one too, considering what it offers. This amp has so many features—yet is so easily controlled by its brilliant footswitch—that you have to marvel at the ingenuity it took to produce such a firebreathing confluence of tubes and technology. Bottom line: If you like the idea of one-stop- shopping convenience for all of your killer Marshall tones, the JVM is the obvious choice.