JTM45 vs SV20?

[Gene Ballzz]

Friendly Folks,

I've not really seen any comparison of the JTM45 and the SV20. While I'm absolutely in love with my SV20H, an all original JTM45 was the "one that got away" in my early days! At the time, I didn't even realize the differences between it and a 50 watt head. I had it in my hands (on loan) for a couple weeks and two or three gigs. What I remember most is that with my Les Paul Custom into that amp and through my '72 1960B, the rig almost seemed to play itself! And it was not deafeningly loud.

Given only a "officially stated" 10 watt difference and the fact that as most of you know, "I've got some great attenuators" at my disposal, so volume is less of an issue. What I'm curious about is the tonal and nuance differences, between the two amps? Would there be anything truly gained by stepping up to a JTM45, from an SV20? I'm getting the amp building itch, and looking at my options.

Thanks Folks,
Gene

 

[Chris-in-LA]

Do it.

 

[purpleplexi]

What he said ∆ Or a slightly more tempered approach might be to get hold of one and have a bake off between the two to make sure you're not looking back through rose tinted specs.
Also as we all know Marshalls of that era were not all created equal - some were stellar some were relatively ordinary. I don't suppose you can find the one you tried.....

 

[GregM]

It's my understanding the jtm had a lil more bass and got dirtier quicker at lower volumes .
That's only what I've read or seen on YouTube .
But to me a jtm sounds like it is my wet dream

 

[fitz]

It's my understanding the jtm had a lil more bass and got dirtier quicker at lower volumes .

I don't have an SV20, but this is exactly how I would describe the difference between my Ceriatone JTM45 and my Origin20.

 

[scozz]

I’ve never played a Jtm45, but l’ve heard they can get a bit boomy, and/or a loose bottom end. Setting the bass control at 0 is not uncommon for some folks. Just hearsay on my part as I’ve said I’ve never played one.

SV20 vs JTM45?

So, while I'm waiting for my DSL50 to sell, I'm researching what my next Marshall should be. I know I want the NMV model, because I just prefer the sound of cranked power valves, which means I need to look at lower power options, hence my most likely options are SV20 and JTM45. A used JTM45 is...

www.marshallforum.com

 

[Tincup]

I just spent yesterday afternoon with my buddy switching from jtm to sv20h, and my new phaez. The jtm was hands down the winner. The complex tone, chime, and low end are incredible. it does get dirty early on the dial, but reacts wonderfully to the guitars volume knob. With an attenuator, I think you’re going to love the jtm. My friend enjoyed it so much, he’s going to build a version of one with fx loop and ppimv. It’s a lot louder than the sv20h. The jtm makes the sv20h sound dry and small when played side by side. We played tele’s, and LP’s with both p90”s and HB’s. We also swapped cabs around to get an equal playing field.

Mine is a painter clone.

 

[tallcoolone]

I’ve never played a Jtm45, but l’ve heard they can get a bit boomy, and/or a loose bottom end. Setting the bass control at 0 is not uncommon for some folks. Just hearsay on my part as I’ve said I’ve never played one.

SV20 vs JTM45?

So, while I'm waiting for my DSL50 to sell, I'm researching what my next Marshall should be. I know I want the NMV model, because I just prefer the sound of cranked power valves, which means I need to look at lower power options, hence my most likely options are SV20 and JTM45. A used JTM45 is...

www.marshallforum.com

I have and I agree. Not my cup personally—boomy and soft without the high mid KERRANG I like from my Marshalls. Different strokes

 

[goldtop0]

Got my SV20H a few weeks ago and have had a JTM45 since the early 2000s.
The SV is an in your face plexi whereas the JTM is more rounded(balanced, if I can use that word) sound, and as folks say, have the Bass on 1 or 2 max, I prefer the JTM overall. I jump the channels on both so get a good palate of tones.
High Treble channel on the SV is noisy hissy so am looking at this with my amp tech to see what can be done about it.
And if you do go ahead with a JTM45 build do it with KT66s rather than EL34s.

 

[EJstrat&JVM]

I never had the pleasure to try a JTM45 cranked, but from what I heard I am sure the JTM50 black flag sounds amazing. Modulus is selling a kit, and it sounds like this with various guitars:

 

[JohnH]

Hi @Gene Ballzz All I know is that you NEED one of these, and we need to hear about it and to hear you play it!

I cant really contribute on JTM45 vs SV20, except that my VM combo is a '45's tonal grandson and the designer Steve Dawson described how it was a starting point for it. When I listen to the VM, set to emulate a '45, Im hearing a big round tone, with bass that may need to be managed, and probably less sizzling rasp from its KT66's than I hear from EL34's. Its a different thing, so you need one!

 

[playloud]

Definitely do it.

There are many different flavors of JTM45 (the recent reissues, particularly the PCB ones, not being the best example), but all of them should be significantly cleaner/warmer/looser than an SV20, all else being equal.

Just be warned that if you prefer ‘tighter’ amps, it may not be your cup of tea. I have a friend who spent years tweaking a JTM45 clone and eventually conceded that he’s more of a ‘modern’ amp connoisseur (2203, Soldano and so on).

If you’re looking for a place to start, Drake-type transformers with KT66s (‘65-‘66ish) seems to be a popular reference point.

 

[Browneyesound]

The answer is always JTM45.

Wait, what was the question?

 

[Mitchell Pearrow]

@Gene Ballzz
You need to build it my friend..

Mitch

 

[dro]

Positively no comparison between Jtm45 and SV20.
I was really interested in the SV20 when it first came out.
Played one at a local GC, for about an hour.
I was really trying to love it.
Yeah, maybe no.
If it would've had IT, I'd still be playing it.

P.S.
GO CHIEFS !

 

[steveb63]

The JTM 45 can be kinda flubby- farty bassy, can be cured with the tone controls and volume.

It's also the only amp in my "untouchable" file. Won't be leaving my grubby paws anytime soon.

But, using due diligence both should be test driven. If possible.

But man that 45 is just......... classy? Classic.

 

[TXOldRedRocker]

Hopefully Gene will find someone with a JTM that'll let him play it. I hope he does.

 

[ken Tucky]

Aside from the tonal differences, the JTM45 feels different than an SV20 (or any other SS rectified amp) as it has a rectifier tube. It provides sag and adds a dynamic, squishy quality when playing notes that gives the amp a distinct personality of its own.

 

[Tincup]

I did put kt66’s in my sv20h, it got a little closer the the jtm, but it’s not a jtm.

 

[K Dub]

Wasn't there a rumor floating around on this forum about a possible JTM20 Studio release?

Studio JTM ST20h

It appears on Thomann but I can't find information anywhere else.

www.marshallforum.com