JTM-45 vs Plexi 50 vs Plexi 100

jmv

jmv

New member
Can someone help explain the differences, sonically, to me?? I'm thinking more in terms of the originals or the general feel of the amp, not really the reissues. The way i understand it, the JTM is the lowest gain, more of a 'bluesy' feel, partly because of the tube rectifier. But if you jumper the channels and dime it, how rockin will it get??

Then, how does a JTM compare to a circa '68 50w plexi?? Can the plexi still do bluesy okay?? What are the differences between the lead and bass circuits, tonally??

And finally, is a circa '67 superlead 100 watt different enough from the 50w plexi to justify all the extra volume that i wouldn't need??


I want to build a marshall kit from metro amps.... of course the problem is i WANT lots of things, and i have very little money. I just want to start getting an idea of what it is i want.

I really dig Cream, Hendrix, SRV, Black Sabbath, James Gang type tones. I'm pretty sure any of these amps could work for most of those kinds of sounds, but obviously i'll have to narrow it down to one eventually!

Thanks,
Jason
 
Re: JTM-45 vs Plexi 50 vs Plexi 100

The plexi's sound brighter, tighter, and louder, and with more crunch. This is due mainy to the use of SS rectification as oppossed to a tube rectifier used by the JTM45. The tube rectifier gives a bit of sag to the 45's, and that imparts a breathy/singing quality to the response when pushed. This is great for blues.

The Plexis gennerally use EL34 tubes, instead of KT66 tubes, giving an brighter overdrive response.

Plexi's still do blues fine though, just listen to vintage Allman Brothers. Live ABB can give a good sample of the difference between 50 watt and 100 watt plexi raunch. Duane is usually using two 50 watt heads and Richard is usually using a 100 watt model.
 
Re: JTM-45 vs Plexi 50 vs Plexi 100

jmv said:
Can someone help explain the differences, sonically, to me?? I'm thinking more in terms of the originals or the general feel of the amp, not really the reissues. The way i understand it, the JTM is the lowest gain, more of a 'bluesy' feel, partly because of the tube rectifier. But if you jumper the channels and dime it, how rockin will it get??

Then, how does a JTM compare to a circa '68 50w plexi?? Can the plexi still do bluesy okay?? What are the differences between the lead and bass circuits, tonally??

And finally, is a circa '67 superlead 100 watt different enough from the 50w plexi to justify all the extra volume that i wouldn't need??


I want to build a marshall kit from metro amps.... of course the problem is i WANT lots of things, and i have very little money. I just want to start getting an idea of what it is i want.

I really dig Cream, Hendrix, SRV, Black Sabbath, James Gang type tones. I'm pretty sure any of these amps could work for most of those kinds of sounds, but obviously i'll have to narrow it down to one eventually!

Thanks,
Jason
Click to expand...
JTM-45's were almost an exact clone of the '59 Fender Bassman and so they use a 5AR4 rectifier tube...the plexi's and all subsequent Marshalls, I'm pretty sure, use a solid state rectifier which has a tighter tone with less sag.
 
Re: JTM-45 vs Plexi 50 vs Plexi 100

Lewguitar said:
JTM-45's were almost an exact clone of the '59 Fender Bassman and so they use a 5AR4 rectifier tube...the plexi's and all subsequent Marshalls, I'm pretty sure, use a solid state rectifier which has a tighter tone with less sag.
Click to expand...

So if one were in the market for a JTM-45, would it make sense to take as close a look at a Fender Bassman (or vice versa, for that matter)?

- Keith
 
Re: JTM-45 vs Plexi 50 vs Plexi 100

KGMESSIER said:
So if one were in the market for a JTM-45, would it make sense to take as close a look at a Fender Bassman (or vice versa, for that matter)?

- Keith
Click to expand...

They sure are similar. We're talking tweed 4x10" speaker Bassman...not a blackface, brownface or silverface Bassman. Speakers are very differant of course. Jensen P10R's vs Celestion 12's. And the JTM-45 takes the negative feedback off of the 16 ohm tap on the output tranny whereas the Bassman has only the 2 ohm tranny tap. The result is more feedback on the JTM-45. Still, I do think they sound very similar and would sound even more similar through the same speakers. Lew
 
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Re: JTM-45 vs Plexi 50 vs Plexi 100

i always thought the bassman and JTM45 models on my valvetronix were so similar that they really didnt need both. and since there is a plexi model why keep the JTM?
 
Re: JTM-45 vs Plexi 50 vs Plexi 100

LoFiBrian said:
i always thought the bassman and JTM45 models on my valvetronix were so similar that they really didnt need both. and since there is a plexi model why keep the JTM?
Click to expand...

Well the Vox is a totally different thing, it doesn't have different circuitry's to emulate the differences accurately, and it doesn't a speaker cab like that of Marshalls.
 
Re: JTM-45 vs Plexi 50 vs Plexi 100

can anyone explain more the differences in a 50w and 100w plexi??
 
Re: JTM-45 vs Plexi 50 vs Plexi 100

jmv said:
Can someone help explain the differences, sonically, to me?? I'm thinking more in terms of the originals or the general feel of the amp, not really the reissues. The way i understand it, the JTM is the lowest gain, more of a 'bluesy' feel, partly because of the tube rectifier. But if you jumper the channels and dime it, how rockin will it get??

Then, how does a JTM compare to a circa '68 50w plexi?? Can the plexi still do bluesy okay?? What are the differences between the lead and bass circuits, tonally??

And finally, is a circa '67 superlead 100 watt different enough from the 50w plexi to justify all the extra volume that i wouldn't need??


I want to build a marshall kit from metro amps.... of course the problem is i WANT lots of things, and i have very little money. I just want to start getting an idea of what it is i want.

I really dig Cream, Hendrix, SRV, Black Sabbath, James Gang type tones. I'm pretty sure any of these amps could work for most of those kinds of sounds, but obviously i'll have to narrow it down to one eventually!

Thanks,
Jason
Click to expand...

As I read this I relized you had several questions that were left un answered...I'll tell you what I know:

A JTM-45 is not so much less gain that a plexi but because of the tube trec it is a little softer in it's attack and not as aggressive as say a plexi head. A dimed out JTM-45 can get pretty nasty but we're still talking in vintage amp terms...this is not a hard rock amp IMO.

Plexi amps are really all over the map in terms of tone mostly because Marshall was always making small changes as they went along...a late 60's 50 watter compared to a JTM-45 the Plexi will have a little more crunch and a little more volume, a little lass sag in the attack and a more agressive/punchy character to it's tone.

FWIW, I think a 50 watt marshall is too loud so the 100 watter is for sure over kill IMO...however if you want MAX clean get the 100 watter...

In Cream, Eric used 100 watters almost all the tiembut they did vary from year...early on he was using a JTM45-100 which like is looks is a 100 watt version of a JTM-45, later on he switched to a model 1959 which is the more common, slightly later 60's Super Lead...Jimi also almost used 100 watters and did the same thing Eric did...early on he used the JTM-45/100 then 1959's. SRV's Marshall(s) were moslt Majors which are 200 watts and fairly different from a regular "Plexi" type amp. Tony Iommi never really used Marshalls...he used Laneys, they are similar in ways but very different in ways too, however I think with a good Marshall you could get close to Tonys tone if you wanted to. Joe Walsh uses loads of different amps but everytime I've seen him witih a Marshall it was a late 60's 50 watter...

I hope that helps
 
Re: JTM-45 vs Plexi 50 vs Plexi 100

Reckless Abandon said:
50 is easier to overdrive. Typically 100 watts will have more thump
Click to expand...

I can attest to the fact that a single 100 has a lot of thump on the bottom, massive headroom, and is louder than **** and will let you play a 5000 seat auditorium.
 
Re: JTM-45 vs Plexi 50 vs Plexi 100

the guy who invented fire said:
As I read this I relized you had several questions that were left un answered...I'll tell you what I know:

A JTM-45 is not so much less gain that a plexi but because of the tube trec it is a little softer in it's attack and not as aggressive as say a plexi head. A dimed out JTM-45 can get pretty nasty but we're still talking in vintage amp terms...this is not a hard rock amp IMO.

Plexi amps are really all over the map in terms of tone mostly because Marshall was always making small changes as they went along...a late 60's 50 watter compared to a JTM-45 the Plexi will have a little more crunch and a little more volume, a little lass sag in the attack and a more agressive/punchy character to it's tone.

FWIW, I think a 50 watt marshall is too loud so the 100 watter is for sure over kill IMO...however if you want MAX clean get the 100 watter...

In Cream, Eric used 100 watters almost all the tiembut they did vary from year...early on he was using a JTM45-100 which like is looks is a 100 watt version of a JTM-45, later on he switched to a model 1959 which is the more common, slightly later 60's Super Lead...Jimi also almost used 100 watters and did the same thing Eric did...early on he used the JTM-45/100 then 1959's. SRV's Marshall(s) were moslt Majors which are 200 watts and fairly different from a regular "Plexi" type amp. Tony Iommi never really used Marshalls...he used Laneys, they are similar in ways but very different in ways too, however I think with a good Marshall you could get close to Tonys tone if you wanted to. Joe Walsh uses loads of different amps but everytime I've seen him witih a Marshall it was a late 60's 50 watter...

I hope that helps
Click to expand...



Thanks for the input!

i think maybe the plexi 50w would be the best bet. Because, at this point in my playing 'career', i really only do bedroom stuff!! 50w is way overkill as it is, but i'm kinda used to it because of the bassman. 100w would be just crazy. With either amp an investment in a good attenuator would be mandatory. I know these aren't practical, but amps are very interesting to me, and i'd love to have real vintage marshall tone... and i think that means taking the volume along with it, to a degree.

Do you know anything about the differences in the lead/bass circuits, in regards to either the 100w or 50w?
 
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Re: JTM-45 vs Plexi 50 vs Plexi 100

i love the 100 but a 50 would be nice also to overdrive for a wider range of distortion if set up with lower distortion rated tubes.
 
Re: JTM-45 vs Plexi 50 vs Plexi 100

yeah thats a good point.

It sounds like you've got a 100, can you tell me a bit more about it?? is it an actual vintage plexi, reissue, botique etc?
 
Re: JTM-45 vs Plexi 50 vs Plexi 100

it's a 95 1959SLP reissue. I got a good sounding one. haven't even modded it. right now has a quad of Siemens Rohre EL-34's and some Sovtek 12AX7LPS pre's in it. all I can say is nice nice NICE! only prob is it's LOUDER than HELL! what were you saying ? lol
 
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