Official original Marshall JVM appreciation thread

James Freeman said:
So the JVM410H is good or what?

I'm looking at the schematic and it's basically a Plexi and a JCM800 with an extra gain stage and a few tweaks.
A couple of minutes of work and I can make Crunch Red a stock 2203, then tweak OD1 and OD2 around that.

@texhex How do you like your so far?
Anyone else appreciates this amp?
Click to expand...
I've probably said it before... but yes. One of my all time favourites.

When I owned my first one circa 2013, I was absolutely gutted when something happened to it. I don't know exactly what, but basically the tone was completely muffled, quiet, dark, and undergained unless I had a buffered pedal feeding the front of the amp - at which point it was perfect.

So I took it on the train up to Bletchley. At the time I couldn't drive, so I had to hulk this thing on the London Underground, and then on national rail, then get a taxi from Milton Keynes to the Marshall HQ. Wife came with me for moral support as I recall!

So we get there and they don't know what the issue is, and they eventually decide it needed a new main board, but they didn't have it in stock there and then, so couldn't fix it immediately. That was fine of course, I wasn't really expecting them to do it there and then. So... about 5 days later, my amp turns up at home, with the issue cured. Marshall were really good in terms of how quickly they turned it around, free shipping and all the rest of it.

But I swear down bruv!! It didn't sound the same. I couldn't figure out why, and eventually I sold the amp after falling out of love with it. There was nothing wrong with it, but it just didn't sound as good. I have no idea why.

But my newest one which I bought 2nd hand either last year or the year before for £850, it is just an absolute monster, and sounds EXACTLY how my first one did when I first got it, before it went poopy.

Here's a super old crummy video of my original JVMJS:
 
James Freeman said:
So the JVM410H is good or what?

I'm looking at the schematic and it's basically a Plexi and a JCM800 with an extra gain stage and a few tweaks.
A couple of minutes of work and I can make Crunch Red a stock 2203, then tweak OD1 and OD2 around that.

@texhex How do you like your so far?
Anyone else appreciates this amp?
Click to expand...
Am I correct in thinking the poweramp uses more NFB than a 2203?

From memory there are a few other tweaks, but its extremely close to actual Marshall circuits within the amp (using some clever relay switching). This kind of concept still appeals to me way more as a modern flagship amp than say what Diezel did with the VH-X.

4 channels is maybe overkill for me, I think some kind of bastard child between a DSL and JVM (with similar flexible switching for the poweramp) would be ideal for me (is that a modded 210?).
 
MirrorProfiles said:
Am I correct in thinking the poweramp uses more NFB than a 2203?
Click to expand...
Yes.
JS version has the same NFB as the JCM800 2203.

sqrt(Watts*Ohm_Tap)*(4.7/(4.7+FB_Res))

JCM800 2203:
sqrt(100*4)*(4.7/(4.7+100)) = 0.9

1959 Super Lead:
sqrt(100*8)*(4.7/(4.7+47)) = 2.57

JVM410H:
sqrt(100*16)*(4.7/(4.7+82)) = 2.16

5150/SLO100:
sqrt(100*8)*(4.7/(4.7+39)) = 3.04

Rectifier Red:
sqrt(100*4)*(4.7/(4.7+INFINITY)) = 0

You get the idea. 🙂
 
James Freeman said:
1959 Super Lead:
sqrt(100*8)*(4.7/(4.7+47)) = 2.57
Click to expand...

1959 with 4 ohm NFB=
flexing arnold schwarzenegger GIF



1959 with 8 ohm NFB=
Tom Hanks Smile GIF
 
FYI, I’m selling my JVM 410 H with MM trannies,
killer tubes etc.
If anyone needed to talk on the telephone,
let’s do I’ll fill you in.hit me up.
I’m not nervous about the buyer liking it because it’s insane.
Once in a lifetime chance!!
 
James Freeman said:
So the JVM410H is good or what?

I'm looking at the schematic and it's basically a Plexi and a JCM800 with an extra gain stage and a few tweaks.
A couple of minutes of work and I can make Crunch Red a stock 2203, then tweak OD1 and OD2 around that.

@texhex How do you like your so far?
Anyone else appreciates this amp?
Click to expand...

I've only had it a few weeks but I absoutley love it.

I think the key for me so far has been not rushing it with this amp. Like treat every mode of each channel as if it is it's own amp and go really slow dialing everything in, lower the gain and volumes and not rush into it.

It was so easy to rip through every channel and mode and get really shitty sounding tones but once I stopped doing that I think I understand what this amp is about now and how to use it and it's fantastic.

I did not care for the stock preamp tubes. I finally did end up leaving the stock Marshall gold labeled Shuguang in V8/9 and put Mesa SPAX7-A in V5/6/7. The Mesa tubes really smoothed out the harshness of the stock Marshall JJs. I don't think I ever really believed in tube rolling making that big of a difference but I proved it to myself by recording a DI of each set and there was a noticeable difference.

I think the stock bias was pretty cold at 26 and I'm sure it would have sounded better if I had played it longer as the tubes heated up but I ended up finally rebiasing it to 32, meausring the inner 2 EL34 tubes with two separate multimeters at the same time. I played through it for about 40 minutes off and on and kept moving the bias down as they would heat up and go slightly higher.

Honestly I don't think anyone should have to go to all that trouble to get this amp to sound good and I don't think I would have either but I wanted to try to get this as close to what I wanted as I could and I feel like it's perfect now.

Compare that to the Badlander where I literally turned it on, went the Crunch channel, put the knobs at 12:00 and turned the Gain knob all the way up and it was rockin right away, a few BMTP tweaks later and it was golden.

The difference is the the JVM can to a shit ton more, but you have to be patient.
 
Orvillain said:
I've probably said it before... but yes. One of my all time favourites.

When I owned my first one circa 2013, I was absolutely gutted when something happened to it. I don't know exactly what, but basically the tone was completely muffled, quiet, dark, and undergained unless I had a buffered pedal feeding the front of the amp - at which point it was perfect.

So I took it on the train up to Bletchley. At the time I couldn't drive, so I had to hulk this thing on the London Underground, and then on national rail, then get a taxi from Milton Keynes to the Marshall HQ. Wife came with me for moral support as I recall!

So we get there and they don't know what the issue is, and they eventually decide it needed a new main board, but they didn't have it in stock there and then, so couldn't fix it immediately. That was fine of course, I wasn't really expecting them to do it there and then. So... about 5 days later, my amp turns up at home, with the issue cured. Marshall were really good in terms of how quickly they turned it around, free shipping and all the rest of it.

But I swear down bruv!! It didn't sound the same. I couldn't figure out why, and eventually I sold the amp after falling out of love with it. There was nothing wrong with it, but it just didn't sound as good. I have no idea why.

But my newest one which I bought 2nd hand either last year or the year before for £850, it is just an absolute monster, and sounds EXACTLY how my first one did when I first got it, before it went poopy.

Here's a super old crummy video of my original JVMJS:
Click to expand...


That sounds mega. Is your neck pickup installed upside down?
 
texhex said:
I've only had it a few weeks but I absoutley love it.

I think the key for me so far has been not rushing it with this amp. Like treat every mode of each channel as if it is it's own amp and go really slow dialing everything in, lower the gain and volumes and not rush into it.

It was so easy to rip through every channel and mode and get really shitty sounding tones but once I stopped doing that I think I understand what this amp is about now and how to use it and it's fantastic.

I did not care for the stock preamp tubes. I finally did end up leaving the stock Marshall gold labeled Shuguang in V8/9 and put Mesa SPAX7-A in V5/6/7. The Mesa tubes really smoothed out the harshness of the stock Marshall JJs. I don't think I ever really believed in tube rolling making that big of a difference but I proved it to myself by recording a DI of each set and there was a noticeable difference.

I think the stock bias was pretty cold at 26 and I'm sure it would have sounded better if I had played it longer as the tubes heated up but I ended up finally rebiasing it to 32, meausring the inner 2 EL34 tubes with two separate multimeters at the same time. I played through it for about 40 minutes off and on and kept moving the bias down as they would heat up and go slightly higher.

Honestly I don't think anyone should have to go to all that trouble to get this amp to sound good and I don't think I would have either but I wanted to try to get this as close to what I wanted as I could and I feel like it's perfect now.

Compare that to the Badlander where I literally turned it on, went the Crunch channel, put the knobs at 12:00 and turned the Gain knob all the way up and it was rockin right away, a few BMTP tweaks later and it was golden.

The difference is the the JVM can to a shit ton more, but you have to be patient.
Click to expand...
If you only knew what that thing sounds like with ample headroom.
A 5 star all you can eat steakhouse.
No more sorta’s and the amp keeps getting sweeter as everything breaks in.
Also you can and need to set the bias much higher then where you set it, I know that compromising spot very well!!’
This does not add noise at all and you need power tubes that can handle higher plate voltages.
Basically, you’re making the amp what it really is and what it can really do without hiss or brittle top end notes. The mid-gain tones are so much better and juicy.
There’s no more of the same sounds pulling the poop out of each other coming all from the same amp that’s supposed to have so many different sounds.
Kinda’ like the same fate of the RoadKing.
With the added Mercury transformers you add
3 lbs more weight, what does that tell ya?
A whole lotta winds in 3lbs man💯.

The JVM is more a computer then an amp.
Go ahead pull it out of the chasis, study the layout
against other Marshall’s.
What’s the glowing difference?
The titanic arrangement of pots with multiple directly connected wires that do what?
Take snapshots of their positions and store where?

A modder dude shoulda’ snatched a bunch when these went on sale and drummed up a mod, like Doodoo, I mean Voodoo amps.
 
Well actshually you can't say good things about JVM anywhere else! I bought jvm410 a month ago, IDK but it's not that noisier or feedbacky than other high gain amps I have. TBH I was reading a lot of shit about it on marshall forum and other place, like it's not Marshall. Well my says it's a Marshall, big white logo. I think noise rants come from the fact they people boost it as they boost 800 and the likes. You don't boost OD1&2, more like (pre)shape the signal.

Regarding digital side. I have Engl Savage mk2 and 4 basic sounds on it each using separate "channel". I can't recall the state of the switches frankly without my midi controller. Was it Mid1 or Mid2 for clean? Bright was turned on or off? Unusable without controller. JVM remembers loop, master, and reverb switches for channels as well as color Magic! Engl should learn.
 
Not guilty - it's very first on the very first google results page. I'm not going past that.
 
chicken said:
Well actshually you can't say good things about JVM anywhere else! I bought jvm410 a month ago, IDK but it's not that noisier or feedbacky than other high gain amps I have. TBH I was reading a lot of shit about it on marshall forum and other place, like it's not Marshall. Well my says it's a Marshall, big white logo. I think noise rants come from the fact they people boost it as they boost 800 and the likes. You don't boost OD1&2, more like (pre)shape the signal.

Regarding digital side. I have Engl Savage mk2 and 4 basic sounds on it each using separate "channel". I can't recall the state of the switches frankly without my midi controller. Was it Mid1 or Mid2 for clean? Bright was turned on or off? Unusable without controller. JVM remembers loop, master, and reverb switches for channels as well as color Magic! Engl should learn.
Click to expand...

I feel like the "noise issue" on my 210h was like just a static level, I would notice it when playing at lower levels at home but it never even registered to me (or any sound guys) as a thing once on stage... so I consider it a non issue personally. Much less noisy than say, single coil hum :idk
 
spawnofthesith said:
Much less noisy than say, single coil hum
Click to expand...
Oh yeah, my Engl Savage is objectively the most noiseless of the pack. If no ground loop it's like -80 white noise. I was obsessive with noise until I realized how much my guitars pickups pick up in comparison. In my limited space I get better noise floor by rotating my ass to another corner than anything else.
 
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