deeaa
January 11th, 2012, 03:17 AM
Marshall JVM 410H review - a few months of use & tests behind:
This amp, as most know, is a quad-channel all-tube amplifier designed for Marshall by Santiago Alvarez. It basically includes a JCM800 series power amp with slightly more powerful transformers, and a series of ingeniously cascadeable preamp/gain stages.
Although the device’s MIDI capabilities and diverse switching- and control options give an impression of a very complex piece of equipment, in the end the amp is surprisingly simple inside, not created with a multitude of fault-sensitive IC boards or anything, but a rather simple, basic tube amp. Only the switching parts and the included reverb are digital. All in all, looking inside the amp reduces the worry of how difficult it could be to maintain in the future – it looks very repairable & sturdy.
It seems to me people react very differently to this amp. And I believe it is largely due to its very effective EQ section, and the fact that it has combined the preamp stages of various legendary Marshall circuits. The latter has obviously resulted in some compromises having been made with the circuits in order to get the channels working smoothly together and means one doesn’t just simply dial in exact replicas of the sounds of old-skool Marshalls. But much of those can be achieved too.
If you are interested in achieving more accurate sounds of older Marshalls, the Internet is your friend and offers guides for several modifications to the amp. For instance, swapping a few capacitors reportedly makes the channel one pretty much 1:1 with the original JMP Marshall ‘plexi’. I have not modded my amp, as I feel it offers just what I need as it is.
Since it is easy to Google for information about the amp, I shall not go into detail about its features like dual loops, serial and parallel, and the huge array of speaker connection options etc. but rather concentrate on my personal view of its usage and features.
My JVM
When I received my JVM it was ’sick’ in that it had been converted to 50W and biased wrong, and had a few tubes in it that were on their last legs. I converted it back to 100W with new Shenglun EL34’sand biased it a touch warm plus swapped a couple of the preamp tubes, and after the repairs it started to work pretty damn well for my purposes.
However from the get-go it was very clear that this is an amp that doesn’t just simply yield the sounds you want, it needs a lot of getting into and adjusting the EQ’s for best results. Also the tube choice is crucial in some respects – the preamps are indeed classic Marshall style and various tubes sound very different. The V1 tube cannot be a thin and glassy Tung-Sols but rather something sturdy and warm – neither did my NOS Siemens tube work there at all – and V2 absolutely can NOT be New Sensor factory products, those will literally blow within one hour of use due to circuit design.
Also, despite the EQ’s look deceivingly simple, they do not affect the sound similarly accross all four channels. In fact the best way to find the sounds on this amp seems to be that instead of starting from 12” positions like on most amps, it’s usually best to turn down the EQ’s all the way and start from there. The sound can change very drastically already at positions 1-3 and according to gain settings. In fact it was so difficult to find the sweet spots I ended up painting little dabs of paint to ’my’ 12 o’clock setting marks. This is important because some people seem to have the wrong notion that the amp is programmable like a POD or something and the knob positions can be saved into memory – this is NOT the case but the potentiometers and the channels are indeed pure analog tube channels, and the only digital thing about them is turning them on or off.
Usage and ’programming’
This leads me conveniently to the channels and their usage. The JVM can be controlled either via MIDI or with its own 6-button controller. I use the latter, and thus the programming in my case is super simple: I press the footswitch button, press a channel on the amp and press save. After that, the corresponding channel turns on from that button. Repeat 5 more times.
This includes the best feature of the amp – not only can you have four independent channels footswitchable, you can also have the same channels directed thru their own master volume, and thus already with the included switch you can have four normal channels plus two solo channels, which can be any of the four channels but with as much more volume as you may ever need.
For my use that effectively six channels is more than enough, but of course, since the JVM can also be controlled via MIDI, you can control it with any MIDI pedal and then you can have much more options to control the sounds. You can hook up an FX box in the loop and have a hundred different FX and amp settings. And that is because – a late stage to mention this – despite the amp has four independent channels, each channel also has three modes, green, yellow and red, corresponding to low, medium and high gain settings. With the included switch you have to select one mode per channel, i.e. have 6 channels at most, but with MIDI you can save any number of combinations, and thus you have effectively 12 different amp channels only restricted with the fact that there are only 4 different EQ’s to use between them. But you can also save reverb on/off and combining this with an FX box looped and its EQ’s settings that yields, IMO, a rather unlimited array of sounds at your disposal quite easily.
But, six channels is plenty for me. Nothing stops you from also saving, say three different gain variations of the same channel to buttons 1-3 and use the rest for the other channels – everything is possible.
There is one big minus to JVM midi control however: the amp does not SEND midi commands. I used to have the JMP-1 preamp and as it also sent MIDI signals I could have an FX box in its loop and the FX box preset would also change when I changed the JMP-1 channel, but with the JVM it won’t change. You have to use a MIDI pedal to control both the amp and your FX box simultaneously. They probably wanted to retain as much of the simple tube amp aspect and only accept incoming MIDI commands, but nevertheless that feature would have been absolutely brilliant to have.
How it sounds.
It sounds like a Marshall should. After much adjustments. Initially, it is far from being the warmest sounding Marshall ever, but with creative and bold EQ use it is not the ‘cold’ amp it is sometimes said to be.
At this point I must stress how great a D/I output the am has. Downright the best I ever came across in any amp. But do not make the mistake of thinking it is a modeler like a POD. Instead, it mimics what you get when you stick a Shure 57 or something in front of the speaker. And that it does frightfully good. I cannot get a better sound by miking it myself at least. It sounds superb, easy to mix – not a ready sound but a basis for mixing and adjustments just like miking and amp, and combined with a room mic somewhere farther away yields superb tones.
In fact the D/I was absolutely instrumental in finally being able to adjust the sounds to my liking, along with using an FX box in the loop. Because I spent a week, several evenings, playing and adjusting the amp first, and honestly, I found it difficult to settle with the settings. Then it just occurred to me to take the amp home, I hooked it up with D/I only and adjusted the sounds to be great with that. And to my surprise , when I took the amp back to its speaker and fired it up – it sounded just like I wanted it to sound. It was much easier to adjust the channels to my liking using D/I than live!
Channels
Channel one can be VERY clean. It is real Crystal Ann. At first it seems like something you’d use only for some metal intro picking, or some RHCP spankiness is easy to get too. But you can get it warm; you just need to jump to a gainier mode like amber or even red, and turn down the gain and play with the EQ. You can achieve rather vintage sounds even. But without mods, do not expect to get any super warm thickness.
The 2nd channel is clearly classic rock genre; more middy and softer. Loads of sounds to be found there.
3rd channel is very tight and modern rock and metal is right there. EQ is important here too.
4th channel is easily so gainy it makes me dizzy, but by lowering the gain it gets similar to 3rd. In any case there are so many gain stages cascaded at that point that a noise gate is pretty much a must-have. Many seem to use two noise gates actually – one in the front and another in the loop, which is also what I have. This gets the amp nicely quiet without killing the gain galore. But the noise is there without the gates.
I do like even the gainiest fourth red mode, but I do use very little gain with that mode.
Overall, the best thing about the sounds is the Marshall-jangly, ringing sound. You know; in leads, tapping or whatever, it gives this singing, almost bell-like sound that feels like there’s a little delay and fills the riffs and makes playing both easy and delightful. Iron Maiden leads, singing and sustaining notes that need not be coaxed out but jump out with great clarity and that bright yet powerful sting only a classic Marshall like JCM800 can usually give to your leads.
This amp, as most know, is a quad-channel all-tube amplifier designed for Marshall by Santiago Alvarez. It basically includes a JCM800 series power amp with slightly more powerful transformers, and a series of ingeniously cascadeable preamp/gain stages.
Although the device’s MIDI capabilities and diverse switching- and control options give an impression of a very complex piece of equipment, in the end the amp is surprisingly simple inside, not created with a multitude of fault-sensitive IC boards or anything, but a rather simple, basic tube amp. Only the switching parts and the included reverb are digital. All in all, looking inside the amp reduces the worry of how difficult it could be to maintain in the future – it looks very repairable & sturdy.
It seems to me people react very differently to this amp. And I believe it is largely due to its very effective EQ section, and the fact that it has combined the preamp stages of various legendary Marshall circuits. The latter has obviously resulted in some compromises having been made with the circuits in order to get the channels working smoothly together and means one doesn’t just simply dial in exact replicas of the sounds of old-skool Marshalls. But much of those can be achieved too.
If you are interested in achieving more accurate sounds of older Marshalls, the Internet is your friend and offers guides for several modifications to the amp. For instance, swapping a few capacitors reportedly makes the channel one pretty much 1:1 with the original JMP Marshall ‘plexi’. I have not modded my amp, as I feel it offers just what I need as it is.
Since it is easy to Google for information about the amp, I shall not go into detail about its features like dual loops, serial and parallel, and the huge array of speaker connection options etc. but rather concentrate on my personal view of its usage and features.
My JVM
When I received my JVM it was ’sick’ in that it had been converted to 50W and biased wrong, and had a few tubes in it that were on their last legs. I converted it back to 100W with new Shenglun EL34’sand biased it a touch warm plus swapped a couple of the preamp tubes, and after the repairs it started to work pretty damn well for my purposes.
However from the get-go it was very clear that this is an amp that doesn’t just simply yield the sounds you want, it needs a lot of getting into and adjusting the EQ’s for best results. Also the tube choice is crucial in some respects – the preamps are indeed classic Marshall style and various tubes sound very different. The V1 tube cannot be a thin and glassy Tung-Sols but rather something sturdy and warm – neither did my NOS Siemens tube work there at all – and V2 absolutely can NOT be New Sensor factory products, those will literally blow within one hour of use due to circuit design.
Also, despite the EQ’s look deceivingly simple, they do not affect the sound similarly accross all four channels. In fact the best way to find the sounds on this amp seems to be that instead of starting from 12” positions like on most amps, it’s usually best to turn down the EQ’s all the way and start from there. The sound can change very drastically already at positions 1-3 and according to gain settings. In fact it was so difficult to find the sweet spots I ended up painting little dabs of paint to ’my’ 12 o’clock setting marks. This is important because some people seem to have the wrong notion that the amp is programmable like a POD or something and the knob positions can be saved into memory – this is NOT the case but the potentiometers and the channels are indeed pure analog tube channels, and the only digital thing about them is turning them on or off.
Usage and ’programming’
This leads me conveniently to the channels and their usage. The JVM can be controlled either via MIDI or with its own 6-button controller. I use the latter, and thus the programming in my case is super simple: I press the footswitch button, press a channel on the amp and press save. After that, the corresponding channel turns on from that button. Repeat 5 more times.
This includes the best feature of the amp – not only can you have four independent channels footswitchable, you can also have the same channels directed thru their own master volume, and thus already with the included switch you can have four normal channels plus two solo channels, which can be any of the four channels but with as much more volume as you may ever need.
For my use that effectively six channels is more than enough, but of course, since the JVM can also be controlled via MIDI, you can control it with any MIDI pedal and then you can have much more options to control the sounds. You can hook up an FX box in the loop and have a hundred different FX and amp settings. And that is because – a late stage to mention this – despite the amp has four independent channels, each channel also has three modes, green, yellow and red, corresponding to low, medium and high gain settings. With the included switch you have to select one mode per channel, i.e. have 6 channels at most, but with MIDI you can save any number of combinations, and thus you have effectively 12 different amp channels only restricted with the fact that there are only 4 different EQ’s to use between them. But you can also save reverb on/off and combining this with an FX box looped and its EQ’s settings that yields, IMO, a rather unlimited array of sounds at your disposal quite easily.
But, six channels is plenty for me. Nothing stops you from also saving, say three different gain variations of the same channel to buttons 1-3 and use the rest for the other channels – everything is possible.
There is one big minus to JVM midi control however: the amp does not SEND midi commands. I used to have the JMP-1 preamp and as it also sent MIDI signals I could have an FX box in its loop and the FX box preset would also change when I changed the JMP-1 channel, but with the JVM it won’t change. You have to use a MIDI pedal to control both the amp and your FX box simultaneously. They probably wanted to retain as much of the simple tube amp aspect and only accept incoming MIDI commands, but nevertheless that feature would have been absolutely brilliant to have.
How it sounds.
It sounds like a Marshall should. After much adjustments. Initially, it is far from being the warmest sounding Marshall ever, but with creative and bold EQ use it is not the ‘cold’ amp it is sometimes said to be.
At this point I must stress how great a D/I output the am has. Downright the best I ever came across in any amp. But do not make the mistake of thinking it is a modeler like a POD. Instead, it mimics what you get when you stick a Shure 57 or something in front of the speaker. And that it does frightfully good. I cannot get a better sound by miking it myself at least. It sounds superb, easy to mix – not a ready sound but a basis for mixing and adjustments just like miking and amp, and combined with a room mic somewhere farther away yields superb tones.
In fact the D/I was absolutely instrumental in finally being able to adjust the sounds to my liking, along with using an FX box in the loop. Because I spent a week, several evenings, playing and adjusting the amp first, and honestly, I found it difficult to settle with the settings. Then it just occurred to me to take the amp home, I hooked it up with D/I only and adjusted the sounds to be great with that. And to my surprise , when I took the amp back to its speaker and fired it up – it sounded just like I wanted it to sound. It was much easier to adjust the channels to my liking using D/I than live!
Channels
Channel one can be VERY clean. It is real Crystal Ann. At first it seems like something you’d use only for some metal intro picking, or some RHCP spankiness is easy to get too. But you can get it warm; you just need to jump to a gainier mode like amber or even red, and turn down the gain and play with the EQ. You can achieve rather vintage sounds even. But without mods, do not expect to get any super warm thickness.
The 2nd channel is clearly classic rock genre; more middy and softer. Loads of sounds to be found there.
3rd channel is very tight and modern rock and metal is right there. EQ is important here too.
4th channel is easily so gainy it makes me dizzy, but by lowering the gain it gets similar to 3rd. In any case there are so many gain stages cascaded at that point that a noise gate is pretty much a must-have. Many seem to use two noise gates actually – one in the front and another in the loop, which is also what I have. This gets the amp nicely quiet without killing the gain galore. But the noise is there without the gates.
I do like even the gainiest fourth red mode, but I do use very little gain with that mode.
Overall, the best thing about the sounds is the Marshall-jangly, ringing sound. You know; in leads, tapping or whatever, it gives this singing, almost bell-like sound that feels like there’s a little delay and fills the riffs and makes playing both easy and delightful. Iron Maiden leads, singing and sustaining notes that need not be coaxed out but jump out with great clarity and that bright yet powerful sting only a classic Marshall like JCM800 can usually give to your leads.