Marshall JVM - How does it work?

Alnico

So the four channel amp has 12 sounds, 3 per channel.

Is this a modelling amp with valves or is it just a clever way of manipulating a valve pre amp ?

I get that it's all programmable for the independent reverb / master volume etc and i get that it's MIDI controllable but how does it actually do what it does ?

Are they reliable amps?

It seems to me to negate a huge amount of Faffery with drive pedals but if they are a typical Marshall gimick then maybe not so much.

They sound good which is a good start i suppose but so does a DSL and a VM and both of them have inherent problems.
I don't seem to hear much about JVM's though.

Is that because they're not popular or that they're cool as hell and dead reliable?

professorben

All I know about is these 3 things. 
1) Rabea Massad used em before he got a Kraken
2) Joe Satch has a modified one as his Sig
3) from what I've heard people say, they are a halfway decent sounding Marshall. 

Cant say I've  tried one, but I gather they are all valve, no modelling. 

The Midi capability had me interested until I stumbled across my Engl, so never got to try one out. 

olafgarten

They are all valve, I think the different modes just bias the power amp slightly differently and change some cap/resistor values.

Grunfeld

Alnico said:

I don't seem to hear much about JVM's though.

Is that because they're not popular or that they're cool as hell and dead reliable?

I used one for about 5 years.  The 100W 410 head.
For gigging:  very reliable. 
Sounds:  It's all in there.  For the pub covers I do I basically had 4 sounds, each assigned on the 6 way footswitch:
clean; crunch; higher-gain-rock; metal territory
For solos:  kick in the second master volume from the 5th button on the footswitch (btw, the amount of power on tap is more than enough.  Ever.)
For the FX loop:  the final button on the footswitch, and I'd kick the echo in and out from there.

The only negative thing about it IMO is the weight.  I got tired of lunking around for gigs twice a week and rehearsals once a week.  It's not light!  I should sell it I guess. 
Great amps.

Alnico

Grunfeld said:

Alnico said:

I don't seem to hear much about JVM's though.

Is that because they're not popular or that they're cool as hell and dead reliable?

I used one for about 5 years.  The 100W 410 head.
For gigging:  very reliable. 
Sounds:  It's all in there.  For the pub covers I do I basically had 4 sounds, each assigned on the 6 way footswitch:
clean; crunch; higher-gain-rock; metal territory
For solos:  kick in the second master volume from the 5th button on the footswitch (btw, the amount of power on tap is more than enough.  Ever.)
For the FX loop:  the final button on the footswitch, and I'd kick the echo in and out from there.

The only negative thing about it IMO is the weight.  I got tired of lunking around for gigs twice a week and rehearsals once a week.  It's not light!  I should sell it I guess. 
Great amps.

Was yours the combo or the head?

I'm nowhere near a new amp but if i could it would be the head i would get.
Thanks for the info.

I heard all those different drive tones and thought of how much could be saved vs pedals.............
It would nearly pay for the amp !

ICBM

Alnico said:

Is this a modelling amp with valves or is it just a clever way of manipulating a valve pre amp ?

It's an all valve signal path, with digital control.

Alnico said:

I get that it's all programmable for the independent reverb / master volume etc and i get that it's MIDI controllable but how does it actually do what it does ?

By changing preset combinations of gain and EQ and adding extra gain stages on some of the modes.

Alnico said:

Are they reliable amps?

Yes, they seem to be. I've only seen one faulty one so far, which was for a switching control problem - which I sent back to Marshall since that's not my area of expertise.

They're certainly much better than the preceding DSL/TSL series, anyway.

Alnico said:

It seems to me to negate a huge amount of Faffery with drive pedals but if they are a typical Marshall gimick then maybe not so much.

There is a learning curve to programming the footswitch, but once you work it out it's fairly intuitive and easy to edit on the fly.

Alnico said:

They sound good which is a good start i suppose but so does a DSL and a VM and both of them have inherent problems.

They're much better than either of those - although the *new* DSL series is much better from what I've seen so far.

Alnico said:

I don't seem to hear much about JVM's though.

Is that because they're not popular or that they're cool as hell and dead reliable?

I don't know. I think Marshall has had something of a reputation problem over the last couple of series, so perhaps they haven't sold as well as they should have.

What's still slightly worrying is that it did seem to need Joe Satriani and his amp tech to show Marshall how to do it right…

If you're going for the 100W version, and unless you *really* need onboard reverb, get the JVM410HJS (Joe Satriani signature model) - even if you can't stand Joe Satriani . It sounds much better and has a few irritating niggles with the original model corrected - and it has a noise gate instead of the (poor) reverb that the standard version does. Even then I would go for the JS and a decent reverb pedal in the loop.

Grunfeld

Alnico said:

Grunfeld said:

I used one for about 5 years.  The 100W 410 head.

Was yours the combo or the head?

It was a 100W 410 head
And you're right, the amp saves a lot of faffing with pedals.
Also, if you're interested when you do decide to get one drop me a PM -- I'm notoriously slow for selling stuff so I may still have it and I'm often in your neck of the woods (MK) so there wouldn't be any courier costs -- cheap JVM for you!

midlifecrisis

i had the jvm 210 which was a 212 combo, weighed a ton, got rid of it mainly for that reason, also found it too complicated, had a good tone tho

Alnico

Grunfeld said:

Alnico said:

Grunfeld said:

I used one for about 5 years.  The 100W 410 head.

Was yours the combo or the head?

It was a 100W 410 head
And you're right, the amp saves a lot of faffing with pedals.
Also, if you're interested when you do decide to get one drop me a PM -- I'm notoriously slow for selling stuff so I may still have it and I'm often in your neck of the woods (MK) so there wouldn't be any courier costs -- cheap JVM for you!

Thank you !

I can't say that i could do that yet however when i can i will let you know, that's very kind of you thanks.

@ICBM - Where would we be without you man !?
That was everything i had hoped for and confirmed what i wanted it to be.

I had seen and heard the JS model but this would be a move to declutter the board and from what i've heard, the std JVM has more than enough to give me what i want however point taken on the reverb etc.
I am nowhere near the leagues of £1200 amps but if i can manage to save up for a second hand one, it looks like a huge win and a massive saving on pedals, most of the time just going round and round in circles losing the price of an amp every few months.........

Thanks guys, that's a great big help.

andyoz

Get the JS one second hand (you'll wonder how you did without noise gates once you use them).

No ones mentioned the cleans yet which are a surprise.  I used to laugh at all the controls when I looked at photos until I owned one.  They are very intuitive actually and well grouped.  You can see exactly what channel/mode you are on with a quick glance at pedal or control panel.

A blue tolex JS head and matching 4 x 12 cabinet on Gumtree near me took weeks to sell at £950....I assume it sold for £900..bargain

ICBM

andyoz said:

No ones mentioned the cleans yet which are a surprise.  I used to laugh at all the controls when I looked at photos until I owned one.  They are very intuitive actually and well grouped.  You can see exactly what channel/mode you are on with a quick glance at pedal or control panel.

A minor irritation is that the channel volume doesn't work in Clean mode - yes, I know that in theory you always want it full up for the cleanest sound, but it just seems an unnecessary extra bit of complication which makes it slightly less intuitive to use, because you have to remember that it's the *gain* that sets the volume of the clean sound.

The only other tiny moan is that the Master 1 and 2 knobs are possibly the wrong way round - 2 is on the left. Several times I've turned up "2" (ie actually 1) trying to get the second volume louder, then finally realised I'm on the other one, pressed the master footswitch and confirmed that indeed this amp is loud enough for anything, ever .

You probably get used to these quickly when you actually own one though.

ecc83

ICBM: So, digital control but how do they do the final high level switching around the valves? Relays?

Dave.

StefB

ICBM said:

andyoz said:

No ones mentioned the cleans yet which are a surprise.  I used to laugh at all the controls when I looked at photos until I owned one.  They are very intuitive actually and well grouped.  You can see exactly what channel/mode you are on with a quick glance at pedal or control panel.

A minor irritation is that the channel volume doesn't work in Clean mode - yes, I know that in theory you always want it full up for the cleanest sound, but it just seems an unnecessary extra bit of complication which makes it slightly less intuitive to use, because you have to remember that it's the *gain* that sets the volume of the clean sound.

The only other tiny moan is that the Master 1 and 2 knobs are possibly the wrong way round - 2 is on the left. Several times I've turned up "2" (ie actually 1) trying to get the second volume louder, then finally realised I'm on the other one, pressed the master footswitch and confirmed that indeed this amp is loud enough for anything, ever .

You probably get used to these quickly when you actually own one though.

The channel volume works on Clean Green, just not on the Orange and Red modes, purposefully to give it a Plexi type feel by all accounts.  The tone stack is the other way around on the clean channel too, for the same reason.

The master volumes are the correct way around on the combo ;-)  I gigged one for about five years and kind of regret selling it as they are difficult to find used for a decent price - apart from the £500 one on here last week...

andyoz

Yeah, that £500 combo that sold here was a crazy amount of amp for the money.

midlifecrisis

bought mine 4 years ago on ebay auction for £330, gigged it for a year and ebayed it for £450, that was the going rate then, new price was about £1200.  the combos always seemd to be cheaper than the heads, supply and demand

ICBM

ecc83 said:

ICBM: So, digital control but how do they do the final high level switching around the valves? Relays?

Yes. I think there's an FET switch somewhere too.

PolarityMan

So I own one of these and have gigged it a lot. It's currently at the techs getting its first set of replacement valves after 7 years.

midi control is a piece of piss, you set the amp how you want then double tap the foot switch button, the light will flash and then you stomp on the ditch you want to set that combination to.

each channel has 3 levels of gain but OD1 and OD2 have a lot of overlap. The higher gain levels are quite silly and are too noisy to use at gig level.

for metal I go back and forth every few months between boosting the crunch channel or OD2 orange with gain set quite low.

despite what other people have said clean green is the only setting that you can't use the channel volume and this mode I find too quiet for sensible use along side the OD channels anyway.

my biggest bugbear with this amp is the audible silence when changing amp channels. I now witch 5ms or so before I need to to compensate but it's still easily the most annoying thing about this amp,

if if you fancy some real world demos everything on my band camp link below is the JVM.

PolarityMan

Oh except for the clean on "as she withers" 

PolarityMan

Bigger review what I done

http://www.thefretboard.co.uk/discussion/68819/marshall-jvm-410h#latest

Alnico

@PolarityMan ;

That's fantastic, thank you.

ecc83

ICBM said:

ecc83 said:

ICBM: So, digital control but how do they do the final high level switching around the valves? Relays?

Yes. I think there's an FET switch somewhere too.

Ah! This is what I would like to dig into. Conventional FETs, the J112 for example could not handle the full signal swing of a valve. They also really need to be driven from a low Z source such as an opamp.

You can perhaps see where I am going here? Are these "all valve" amplifiers actually using digital control on a solid state signal path then amping that up for valves?

Naturally(!) "I" have no problem with that but others might. LOVE to know!

Dave.