Looks like Marshall have a new amp coming out this Friday

Stratavarious · July 2023

It ain’t a spare for my late 70’s JMP Master Lead II… pass.

Is it me, or does it sound less that stellar in the various demos?

HandwrittenHero · July 2023

https://youtu.be/VAibmd4-cMY

Struck me as a decent demo of it actually. A telecaster was a good choice to illustrate the journey through a pretty bright sound into filling out by jumping then onto returning some poke with presence.

GavRichList · July 2023

It’s a nice sounding amp, though I wouldn’t say it sounds particularly close to a JTM45 to my ear. Doesn’t seem to have the fullness, and the break-up characteristics are different to me - somehow loses too much note definition.

kossofffan · July 2023

If they had put this new Studio JTM circuit inside a MkII Origin OR120H with a single input & a tilt knob you would never guess it's 'based' on a vintage JTM.
When will they wake up & install a master volume on the rear panel, like I did to a 1959HW Super Lead.

rze99 · July 2023

The Pete Thorn demo is the best I’ve seen.

If I didn’t have a vintage Marshall stack I would be a buyer I think.

Johnny333 · July 2023

kossofffan said:

When will they wake up & install a master volume on the rear panel, like I did to a 1959HW Super Lead.

Couldn't agree more!

TTBZ · July 2023

Pete Thorn's demo is awesome, sounds great with all his guitars. JTMs in general seem better with singlecoils & P90s to me, humbuckers get too wooly and muddy unless they're very clear/bright or use a treble booster with it. I can't seem to get a usable sound for me but I'm more of a JMP/800/Jubilee player!

GavRichList · July 2023

The Thomann demo sounds great. You have to get past the YOUTUBE!ENTHUSIASM! but they show the amp really well. Sounds a bunch better to me with the 2x12

noisepolluter · July 2023

Waiting for the first SV20/ST20 comparison vids - I’d definitely use an attenuator with one of these but I’m also very interested to know which would handle pedals better, what the respective bright cap sizes are etc

Ddigger · July 2023

rze99 said:

The Pete Thorn demo is the best I’ve seen.

If I didn’t have a vintage Marshall stack I would be a buyer I think.

Anyone have any idea what the LP shaped guitar he plays with no selector switch is?

Discoloured fretboard markers and double white HBs make me think Japanese 80s? Greco?

musteatbrain · July 2023

It’s a Scala Underdog @Ddigger ;

Ddigger · July 2023

musteatbrain said:

It’s a Scala Underdog @Ddigger ;

Never heard of it, but I'll do some digging!

Thanks.

guitarjack66 · July 2023

Are those Marshall amps,in general,as heavy as they look?

soma1975 · July 2023

nope

Broseley_Bob · July 2023

What’s the difference between this and the SV20H other than the power amp tubes?

ICBM · July 2023

Broseley_Bob said:

What’s the difference between this and the SV20H other than the power amp tubes?

There should be quite a few circuit differences as well, if they’ve done it right. The JTM45 is much less evolved into the bright, aggressive Marshall JMP Lead model tone - essentially it’s the Bass model, with different power valves, valve rectifier (which they may or may not have simulated), different OT ratios and a lot more negative feedback. It’s much warmer, fuller and more compressed than the JMP.

mo6020 · July 2023

I don't need one of these, but I want one of these.

Kent747 · July 2023

I'm very interested - but want to play it in person. Had a JTM for years and can still hear the sound in my head.

randella · July 2023

I'll stick my neck out and say it's a nice looking thing. There's deffo a market for them I reckon.

I haven't the space for a 2203 JMP/JCM800 plus cab so I've made do for now with a new DSL combo. It'll be the same with this - if it does a reasonable facsimile of a JTM45, it's surely a winner for those who love that sound but haven't the room, cash, or marital tolerance to get a real JTM45 or Bassman reissue into the house.

earwighoney · July 2023

ICBM said:

Broseley_Bob said:

What’s the difference between this and the SV20H other than the power amp tubes?

There should be quite a few circuit differences as well, if they’ve done it right. The JTM45 is much less evolved into the bright, aggressive Marshall JMP Lead model tone - essentially it’s the Bass model, with different power valves, valve rectifier (which they may or may not have simulated), different OT ratios and a lot more negative feedback. It’s much warmer, fuller and more compressed than the JMP.

The JTM was based on a tweed Bassman right? A few modern(ish) amps favoured in the more traditional side of metal (ie bands that sound like Sabbath) use Bassman style circuits.

This new JTM amp sounds great, I think it would make a perfect combination to play Sabbath riffs with.

ICBM · July 2023

earwighoney said:

The JTM was based on a tweed Bassman right?

Yes, a direct copy of the 5F6-A but with a different transformer ratio (for a 16-ohm output instead of 2-ohm).

earwighoney said:

A few modern(ish) amps favoured in the more traditional side of metal (ie bands that sound like Sabbath) use Bassman style circuits.

That's because the classic Iommi amp is the Laney Supergroup, which is effectively a Marshall Super Bass copy (although again with different transformers, and doesn't sound quite the same), and the Super Bass is not far from a high-powered JTM45... so still 5F6-A derived.

earwighoney said:

This new JTM amp sounds great, I think it would make a perfect combination to play Sabbath riffs with.

If you want a low-power Sabbath sound, get a Laney LA30BL - it nails it dead on.

Dave_Mc · July 2023

ICBM said:

earwighoney said:

The JTM was based on a tweed Bassman right?

Yes, a direct copy of the 5F6-A but with a different transformer ratio (for a 16-ohm output instead of 2-ohm).

That's what I thought.

From the MusicRadar review https://www.musicradar.com/reviews/marshall-studio-jtm-st20h-20w-head-and-st212-cab-review :

"It can't be understated just how much of an impact Jim Marshall's JTM tube amp had on the emerging world of rock 'n' roll - with the "coffin logo" version from 1964 being seen as the holy grail by many players. Yes, the original may have been inspired by the beloved Fender 5F6-A Bassman, but the JTM was a different breed altogether - thanks in part to the use of British KT66 output and ECC83 preamp valves. This new class of amplifier delivered a tone and power that players of the day had never experienced and well, the rest is history. "

Hmmm. So a (more or less) straight clone of an already-existing amp produced a tone which no-one alive at that time had experienced. Or the newer, more modified version with KT66s did, I guess. Except this low power version is a copy of the original clone with 5881s, not the slightly newer-less-cloney KT66 one.

Who writes this crap? Does no-one check it? Even if you didn't check anything else, reading through that single review/article once would tell you something doesn't add up.

I mean I dare say it sounds great (and darned if I don't want one regardless... well, I'd probably get one of the other Studio ones first if I ever get round to it, but still), but come on.

(Can this new one take KT66s out of interest?)

EDIT: Might be best to ignore this... I had a migraine. That's my story and I'm sticking to it!

ICBM · July 2023

Dave_Mc said:

Hmmm. So a (more or less) straight clone of an already-existing amp produced a tone which no-one alive at that time had experienced. Or the newer, more modified version with KT66s did, I guess.

The different output impedance makes a big difference, because Marshall - Ken Bran and Dudley Craven - didn't correctly compensate for the much higher output voltage (the OT turns ratio is the square root of the impedance ratio, so 2.83 times higher), they just copied the circuit values exactly... the result is that the JTM45 has almost three times the negative feedback of the Bassman, and a very different overdriven sound.

The other huge difference is that the Bassman uses four 10" Jensens wired in parallel in a lightweight open-back pine cabinet with a floating baffle, and the Marshall uses four 12" Celestions wired parallel-series in a heavy closed-back ply cabinet with a firmly-braced baffle. The cabinet was actually all Jim Marshall's work and probably even more important than the OT ratio.

Both these are more important than the 5881/KT66 difference and the 12AX7/ECC83 *non*-difference - there isn't any, other than the minor difference between valve brands, 12AX7 and ECC83 are just the US and UK designations.

roberty · July 2023

ICBM said:

earwighoney said:

This new JTM amp sounds great, I think it would make a perfect combination to play Sabbath riffs with.

If you want a low-power Sabbath sound, get a Laney LA30BL - it nails it dead on.

Can't get enough of mine. My favourite amp ever

roberty · July 2023

Might be looking to trade my big JTM 45 for something more modern. I have a lot of four hole amps

Dave_Mc · July 2023

ICBM said:

Dave_Mc said:

Hmmm. So a (more or less) straight clone of an already-existing amp produced a tone which no-one alive at that time had experienced. Or the newer, more modified version with KT66s did, I guess.

The different output impedance makes a big difference, because Marshall - Ken Bran and Dudley Craven - didn't correctly compensate for the much higher output voltage (the OT turns ratio is the square root of the impedance ratio, so 2.83 times higher), they just copied the circuit values exactly... the result is that the JTM45 has almost three times the negative feedback of the Bassman, and a very different overdriven sound.

The other huge difference is that the Bassman uses four 10" Jensens wired in parallel in a lightweight open-back pine cabinet with a floating baffle, and the Marshall uses four 12" Celestions wired parallel-series in a heavy closed-back ply cabinet with a firmly-braced baffle. The cabinet was actually all Jim Marshall's work and probably even more important than the OT ratio.

Both these are more important than the 5881/KT66 difference and the 12AX7/ECC83 *non*-difference - there isn't any, other than the minor difference between valve brands, 12AX7 and ECC83 are just the US and UK designations.

Yeah I wondered that about the 12ax7 versus ecc83, I always thought they were basically exactly the same. But I didn't say that in case I was wrong. So I didn't say the bit I was right about and did say the bit I was wrong about, lol.

I'm sure I've seen that about the negative feedback before (probably posted by you, lol). But I forgot!

Yeah good point about the speakers/cab. I do know that bit, lol.

EDIT: Not sure what I was thinking when I posted... can I blame it on a migraine? Anyone who's paid any attention to my silly posts over the years might be tempted to think I get a lot of migraines...

ElectricXII · August 2023

Is it just me, or does any one else strongly dislike the aesthetics of these? The "coffin" logo is especially dreadful.

RiftAmps · August 2023

Someone pointed out to me that this sounds very much like a HRD and now that's all I can hear when I watch the demos.

GavRichList · August 2023

ElectricXII said:

Is it just me, or does any one else strongly dislike the aesthetics of these? The "coffin" logo is especially dreadful.

yeah I don't like that either...that said, if they did my preference it'd look exactly like the SV20.

p90fool · August 2023

ElectricXII said:

Is it just me, or does any one else strongly dislike the aesthetics of these? The "coffin" logo is especially dreadful.

That's what the very first Marshalls looked like, it's not just a random styling exercise.

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Looks like Marshall have a new amp coming out this Friday

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