Today I have a guest writer to The Rock House Blog. They own a Marshall JVM series amp and did a review on what they have experienced with their amp.
More information about Marshall Amps can be found at http://www.marshallamps.com/ .
Features (5/5): This is the newest in the line of Marshall Amplifiers. All these feature a cascading gain system, and have no diode clipping, instead relying fully on tube saturation for their overdrive and distortion sound, making it the first true high gain amplifier by Marshall. All models feature Clean, Crunch, and Overdrive channels. Each channel has three levels within them, essentially making them between 6 and 12 amps in one. They all feature five ECC83 preamp tubes and two or four EL34 power tubes depending upon the wattage (2 for 50, 4 for 100). They also feature a power amp serial loop (not for FX), and a parallel/serial effects loop with a wet/dry adjusting knob. Also featured is an emulated line out that is activated when the amp is in standby mode for silent recording. All have studio quality digital reverbs. All models have speaker outs for 1 x 16 ohm cabinet, 2 x 16 ohm or 1 x 8 ohm, 2 x 8 ohm or 1 x 4 ohm external cabinets or you would use the ohm rating for the internal speakers when connecting both the internal speakers and an external cabinet on a combo amp.
The main difference between the overdrive channels on the 4 channel model vs. the two channel model is that the two channel model’s overdrive is the same as the OD2 on the four channel model. It is the midrange center that changes. The midrange on OD1 is 650 Hz like every other Marshall, and OD2 has a center at 500 Hz making it more suitable for modern metal.
The amp heads are designated by an H and the combos are designated by a C after the numbers. The 205 is a two channel Clean/Crunch and Overdrive, and is 50 watts and retails for around $1700. The 210 is the same amp but is 100 watts and retails for $1900. The 410 is a four channel 100 watt amp and retails for $2200. Add about $400 for the combos. The combos for each model have one 12” Vintage 30 and one 12” Celestion G12H30, and weigh between 70 and 85 lbs. The small combo is the 215C which is a 50 Watt 112 with one G12B speaker. The amp heads weigh around 40 lbs.
Ease of Use (4.5/5): This is not a plug and play amp out of the box. There is a four to six switch pedal that comes with it that needs programming. It isn’t difficult. It comes preset from the factory. It has a memory in that it remembers what you had it set to on your last usage, but it of course will not remember your knob settings. That is something we’ll probably see in the next generation.
It also takes time dialing in a tone, just like with every other amp. It took me about two weeks to get the amp to where I like it.
Sound (5/5): I’m running my 410H through a 4 ohm “modular” 412 cabinet (two 212 cabs) with two Celestion Greenbacks, and two Celestion Vintage 30s. First, this amp is loud. Very loud. The Master Volume is immediately before the power tubes and as such doesn’t induce the clipping that many amps use to get distortion. You know that trick about turning up the volume/gain to about 8 and setting the master to 2? It doesn’t work that way. The master just lowers the overall signal; hence it is a true master volume. It does sound reasonably good at lower volumes but if you want to get any kind of power tube saturation you will need something like a THD Hot Plate (I’ll have this in a subsequent review).
The amp is a pedal killer. You will find you won’t need any distortion or overdrive pedals except for something like a vintage fuzz or muff. Time based FX are useful with it in the parallel loop. It is suggested that if you use guitar FX that you turn the “Mix” knob all the way to WET to avoid any dephasing of the signal.
If you don’t read the directions and plug your FX into the Preamp Out and Power amp In jacks your signal will be all messed up. Your pedals will get warm and there is a possibility of damage to the pedals. This is because it is a full line level signal. So I recommend reading the manual first.
The tones available from the amp are amazing. The clean channel Green is very clean. Your only boost available with it is the Master Volume boost. The Orange and Red settings are quite organic in feel, that is the harder you pick the more crunch you get, or if you dial back the volume on your guitar it cleans up very nicely.
The Crunch channel will give you sounds similar to a JTM45 Plexi on Green up through that of a JCM 800 on Red.
The OD1 Green is similar to a hot-rodded JCM 800. Orange gives hard rock/heavy metal tones. OD1 Red adds even more gain.
OD2 does the same thing except the midrange adjustment is at 500 Hz.
The overdrive channels on orange and especially red tend to have quite a bit of hiss that is very noticeable at high volumes. Still it is much less than a Boss Metal Zone. Marshall Amps tend to be picky about your pedal power so make sure you use a good power conditioner that gets rid of 60 Hz hum, and make sure your outlet is grounded. Also your pedal power should be clean. My 1-Spot had to be retired because the hum was horrid. Boss PS-120 hums as well, and so does the Ibanez 9v power supply. I highly recommend the Gator power supply for your pedal boards ($40), or if those don’t do the job, the Dunlop or Voodoo Labs ($100 to $160).
You will notice that there is a slight delay when you switch channels. The time is 50 milliseconds, or 1/20th of a second. This was done on purpose to prevent a “pop” when you switch channels. It was kind of a damned if you do, damned if you don’t thing for Marshall. If they did the instantaneous channel switch you’d hear a pop, and people would complain. So they eliminated the pop, and people will complain.
Noise reduction: Like with most high gain amps, the high gain channels OD1 and OD2 on Orange and especially Red have a lot of preamp hiss, and residual hum from your pedal chain unless you use batteries. Furman power conditioners don’t help much on this, nor do EBTech hum eliminators. What I’ve found works the best with this is something from www.isptechnologies.com called the Decimator G-string. Your guitar plugs into this, then into your pedal chain, then into your amp, then out the parallel loop back into the Decimator, then into your clean effects, then back into the return of the parallel loop. This thing gets rid of ALL hum and hiss without sucking tone or killing sustain unless you have the thing turned up way too high. The Decimator G-string runs $250. It’s the last noise gate you’ll buy. Don’t even think about the Boss NS-2 here. You’ll need two of them, and they don’t work that well in comparison – they suck tone and kill sustain.
Reliability(?): As with everything, something can go wrong. If you get this at Guitar Center, I’d get the extended warranty. Otherwise the warranty is 5 yrs parts and 3 years parts and labor and is transferable only inside the United States. I haven’t had to deal with anything here yet. I hope never to deal with it.
Value (4.5/5): You get quite a lot for your money, but then at this price you should.
Overall (4.5/5): Great amp. Marshall’s new flagship. If you want the Marshall sound you need a Marshall. There is no other amp that will give it to you. There are no pedals that will make another amp sound like a Marshall. You can get close but after you’ve spent all the money chasing it, you might as well have bought the real thing.
They do not recommend pulling two power valves from the 100 watt head/combo to reduce it to 50W. Look for them to void the warranty if you do this. They recommend a Power Brake instead, but those are expensive and heavy.
I would definitely gig with this amp, but I wouldn’t gig without a backup. My backup is a 5150 (see future review). There are reliability concerns. Schematics aren’t readily available to anyone but an “authorized service center.” Amp biasing needs to be done by a technician, which means power tube changes need to be done there. Reason for this is that the trim pots used for biasing are not accessible without removing the amp from the chassis, which is no small task. You shouldn’t need new power valves for 18 months or preamp valves for at least 3 years under normal use. They also say that power valves and preamp valves must be changed by a qualified technician. What is a qualified technician? So if you value your warranty which is below in full, you take the amp in for valve replacement and don’t do it yourself.
Pros: 6 to 12 different sounds in one amp depending upon model. Versatile. First Marshall high gain amp that does not use diode clipping.
Concerns: Complex. Relatively new. Amp techs may not really understand this thing yet. Cost for shipping to a warranty center is on you, so best to return it to the store where you got it if anything goes wrong.
Comparable products: Mesa Boogie Road King; Hughes & Kettner Trilogy.