Marshall JVM410H first review

[deeaa]

Well, I got a change to play with the amp for over an hour today.

When I first booted it up and started dialing in a clean sound, man I was disappointed at first. Cleans sounded really papery, thin and buzzy.

And finally I ended up using over 30 minutes just on the clean channel, trying to get it sounding not very brittle and top buzzy. I did manage to dial in quite a nice sound, but, seriously, it's still a far cry from the Ceriatone's warm, lush and deep sound.

The clean(ish) sounds I get from the clean green are now quite british-feeling, quite bright perhaps too, but rather usable and OK. I can't get a very clean clean sound out of it other than using so thin a tone it starts to sound more like an acoustic guitar than an electric...but it's a Marshall and I don't really need very clean sounds anyway. If you like sparkling, pure sounds like on metal picking and such, those are easy to get, but a thicker, warmer and crunchier clean was very hard to get. Now it is good, but the highest strings do sound kind of dead and too metallic to me still, almost like they touched the frets a little too much is the best I can describe. Clean green mode and on single coils it's rather clean but if I hit a chord on bridge pup, it's Back In Black level AC/DC almost. But I would have expected a 100W amp to be able to yield a thicker yet clean sound nicely. Will have to do some more tests but I doubt it does that, anything 'Fendery' or EL84 type thick clean sound.

The crunch channel proved pretty much as hard to get a good sound out of. A very bright modern AC/DC is a given, but dialing in any depth and warmth seems hard. I did manage to get a pretty good sound finally by really digging deep into EQ, but it is nothing extraordinary. I think I will be able to get a very good driven rhythm sound out of the green mode, if I can get it a little punchier&warmer still without adding buzz.

OD1 channel was much better, then. In green mode, I could immediately dial in a helluva lead tone that wails very well - again more on the cold side than warm, but great definition and sustain, very easy to play with notes just jumping out like only a classic Marshall does, and screams and feedbacks beautifully, superb sustainand no noise whatsoever. Gain has to be like only halfway up for a good sound. Amber and red versions of the channel only add too much saturated buzz to it, and on those you need to almost cut off gain and still it gets noisey.

Od2, well, very hard to find uses for that channel for me. Green mode and gain almost off it is still way more drive than you need for, say, Metallica etc, and any more or the other modes, it just becomes a thick singing but not too clean a buzz I don't know for what I'd use. Waaaayyyyy too much drive for anything really, IMO.

But to sum it all up, on the plus side I did manage to get a very nice variation of sounds, and I really really like the lead tone I get from OD1 green.

I could not find a single thing where I'd have liked amber and red modes though...on all channels, they just add an extra layer of buzziness to the sounds, and it seems to me I'll likely only be using green modes and the first three channels with masters high and gains low and also EQ's drastically cut to give it some warmth.

Overall the amp is a bit too bright and not very deep sounding at all - but the built-in reverb helps battle it some. I think it will prove to yield good sounds for recording and band playing though, and I'm happy so far!

[Eric]

Cool. I'm not familiar with this amp, but it sounds like it has 4 channels, or at least quasi-channels. What do they different colors do, at least in theory? Are they added gain stages or do they drop the amp power or something?

[Robert]

Did you buy it new or used? How much?

[deeaa]

Used...swapped it direct for my Ceriatone.

Yep 4 channels, all 3 modes...for now it seems the green modes are all I like, though, but maybe I'll find uses for other modes as well. They indeed seem to just 'warm up' the channels with added saturation and drive in stages; likely they also change the way EQ works on the amp.

I just noticed a few things about the amp:
- It needs to warm up WELL before playing. I mean, 5 minutes or so, and if you start playing it cold it has no bass whatsoever and sounds quite brittle.

- I think I may have a bad tube / worn tube somewhere, because I doubt the clean high end should have that kind of a weird tingly zing there somewhere underneath so much...could be a tube going out soon. Maybe best just retube thru and thru.

- I may need to check the bias on the amph.

I will post a video demo clip very soon now, just upping to YouTube!

[deeaa]

http://www.youtube.com/watch?v=AX89jeX9Xi4

[Robert]

If you got it used, it's quite possible it would benefit from a retube (which costs a bit....)

The amp can sound brittle, agreed. It seems to me the eq reacts quite differently compared to say a Fender.

Keep turning knobs, and get to know the amp. It took a long time for me to "get to know it".

[Eric]

It sounds pretty good, maybe a bit overly loud? Was the camera perhaps distorting? It seemed pretty fuzzy on OD2, I'll agree with that. But overall not bad for a first spin on a new amp, particularly one as deep as that JVM.

I know you're Mr. active pickups, but I wonder if it seems to have too much gain because of how much signal you're shoving in from those EMGs.

[Ch0jin]

Used...swapped it direct for my Ceriatone........

Wow. I did not see that coming. I've heard nothing but glowing praise of that amp from you. I just assumed you wanted another amp, not a replacement. I don't want to derail the thread, but what was your motivation to switch so drastically?

[Robert]

Wow. I did not see that coming. I've heard nothing but glowing praise of that amp from you. I just assumed you wanted another amp, not a replacement. I don't want to derail the thread, but what was your motivation to switch so drastically?

Let me guess. That grass had more of a greener, more attractive look from that other side where he was standing? :)

[deeaa]

Yeah, I had no delusions the JVM would sound better than the Ceria, but I'm pretty sure it'll suit my needs much better.

Despite having such a great sound, the Ceria had two issues - first, I needed many pedals with it, a way too complex a pedalboard, and secondly, having just one channel there was not enough available boost for leads, simply not enough adjustment room.

Because I only usually play thru an amph like 1-3 times a month, it seemed stupid that every time I did, I would be pissed that I could not get my solos to work loud enough, and also it seemed stupid to have such a load of pedals and such an amp just sitting there.

I figured, even if the JVM might not have the same sound quality, I would at least finally get my leads heard, and get rid of the pedalboard which means I gain also well over $200 just by selling off extra pedals.

I would have kept the Ceria for sure had I had some $1000 extra around, but I don't...

[Robert]

The JVM is awesome, you just need some time with it.

Since you get so much gain in the Clean Green, I'm wondering if it's because of the active pickups? Can try with a guitar that has passive pickups?

[deeaa]

OK it seems the bias on the amp is way off and the power tubes in dire need of replacement.

When I looked at the tubes closer w/the chassis open, the first thing I worried about is they all look very different in that on two of them the white Marshall text is browned and slightly 'burned in' looking while on the two others the text is pristine white.

I went ahead and checked the biasing, and already before I touched anything, I noticed the 1st tube in the row had a brighter burn in the 'base' of the tube than the rest of the three, which I had not noticed from the outside.

On to biasing, which is easy enough on these amps, just measure off the 3 posts in the middle (mid is ground); on one side I measured 29, something, so apparently that is WAY cold. On the other side I read 50 something which is closer to correct I understand (stock should be 60Mv, but people do go as high as 70 quite regularly). It only took a small nudge to get both up to 60,3.

I went to get a guitar to test it out while I let it settle, but when I turned back I noticed the entire first tube glowed red all over, I mean, the full plates were red, so I quickly turned off the amp. So it was definitely just about to blow...

Next up, will go get a new quartet of tubes and see what happens. Boy I hope that is all that is wrong, I'd hate it if the amp needs more repairs right off the bat.

[Ch0jin]

Yeah, I had no delusions the JVM would sound better than the Ceria, but I'm pretty sure it'll suit my needs much better....

Ah that's cool, that's basically what I suspected.

I tried a JVM out in a store a little while ago and actually really liked the clean, but I also thought the red channel was wayyyyy too gainy (and I have a Peavy Ultra which basically has the "red" channel of a 5150!) The hardcore metal guy I work with had a bit of a shred and announced he'd be holding on to his JCM900 for metal too.

[deeaa]

Okay,

I got four new Shungl..ung something Golden Dragon EL34's today, matched quartet, should be rather good toobs.
Put them in and biased; it was way off still but now I got it to reading 63 on both.

NOW it sounds completely different, it kinda woke up the first time, with lots of punch and also low end, if not as low freqs as in the Ceria, but anyhow, sounds pretty damn good already and I guess almost like it should. Still a faint scraping ultra-high sound with higher strings on clean in the background...strange tingle, almost like a real spring reverb vibration tingle but harsher, kinda like a string grating on too low frets. Hell I have to check maybe that's exactly what it is actually...anyway...

BUT there is something still clearly wrong.

Each green channel works and sounds good, and the clean amber mode works, BUT when I kick in red, no sound at all. Well maybe a VERY faint sound.
Same with the crunch...I think...yes it also had green and amber OK but no sound on red mode.

On OD1 and 2 only the green modes work, and work well too, but no sound on either amber or red mode.

I had one preamp tube that looked very weak in comparison to the others, and put a Sovtek 12ax7WB on it. No change.

Likely there is one tube gone bad, that is a part of a required gain stage in OD1&2 amber and green channels as well as on clean/crunch red channels.

Which one? They all look fine to me now, concerning color and light of the red glow. JVM forum will know...

[Eric]

That's interesting. You figure it's a defective power tube or a bad preamp tube? I don't know how these amps work, but I'd guess you're talking about a preamp tube?

Good luck with it. I'm glad you're making some progress with it.

[deeaa]

Yep, power tubes are fine & well biased now, no problem there.

The amp has three dual triode preamp tubes, each used with either half on at one time in different combinations.
The V1 b side is the only one that is required for red & amber modes so it has to be the very first tube that's 'half' shot - only the first triode works in it apparently.

I bought three new tubes and will replace the V1 and V2 with Tung-Sols and keep the original V3 as it apparently works fine, and I still have an old Siemens NOS tube on backup for V3 (it can't be a newer design tube for cathode follower position) as well as one Sovtek and one original Marshall tube. If any of the rest of the preamp tubes fail (six in total) I have some backups too.

Will go see what happens with it tonight!

[deeaa]

Oh yeah...NOW it sounds like it should! Hello JCM800 & at, missed ya already!

Yep the cleans work now too. No it's not the sweet & soft sounding amp with a smooth thick breakup, but instead it's the Marshall bite a plenty, superbly fluid lead playing and a midrangey, cleeear crunchy drive that records so marvellously and cuts thru the mix, if sounds a bit brittle in person & alone with the amp sometimes. Plenty of bottom too.

I found the best sounds for me to be OD1 and OD2 both in Amber mode BUT with the gain around only two. That gives it a great chunky attack and enough drive to sing and scream aplenty, yet keeps it totally noiseless. I also cut the highs to like 10 o clock, boost the mids way high especially on OD1 and boost the bass a little. Superb rock sounds with my EMG85's.

That way also when I drop to neck single on OD1 it's clean enough for a cleanish, yet warm and thick and a little breaking clean sound that works very well. I could live with just those two.

On crunch I get a much warmer, bluesier tone but it lacks punch in comparison,will have to tweak it more.

Clean channel...meh...too clean, and when getting dirty doesn't warm up enough no matter what. I got much better cleans for my taste on OD1 dropping the guitar's input.

It will be good for some RHCP style funky bits, or the hotter side for british-style Vox-like powert chords that ring huge like on a Bluesbreaker, but definitely will be less used for me. I think I will live mostly in oD1 amber and for leads that with a volume boost or od2 amber with very little gain.

Happy camper now!

[Eric]

Ah good. I'm glad you got it figured out. It wasn't sounding so good for a little bit there.

[deeaa]

Yeah - PHEW I was happy it didn't turn out a lemon after all, just bad maintenance of tubes...

[Ch0jin]

Great to hear you got it sorted out! I was thinking I must have had really bad taste in clean tone because the one I played sounded pretty nice ;)

Note: I reserve the right to revise my call on "nice cleans" when I ever get this JTM45 built though.

[deeaa]

JTM will have much better cleans...these JVM cleans are great if you like 'clean clean', it doesn't do a proper 'clean with tube power stage warmth applied' very well. And I do prefer the latter.

[starskyroth]

Cool,
I'm not fa miler with this amp,
it sounds like it has minimum 4 channels in those one should be played all time Metal music it's heavy....