LDR!!!

[lukemc]

mats i think you are getting your plexi's confused.
im talking about a JTM45 not the 1987 with el34s.
i dont know about yours but mine with the master volume maxed and even moderate detail and body. with the mid boost in it definetly has the same if not more as a JTM45.
HDR has too much gain for me IMO. sounds like a hotrodded plexi, which is exactly what it is supposed too.

[Angus]

mats i think you are getting your plexi's confused.
im talking about a JTM45 not the 1987 with el34s.
i dont know about yours but mine with the master volume maxed and even moderate detail and body. with the mid boost in it definetly has the same if not more as a JTM45.
HDR has too much gain for me IMO. sounds like a hotrodded plexi, which is exactly what it is supposed too.

Like you I'm fond of LDR, but can you not find a gain level you like on HDR by bringing the pre amp settings down and the power amp up?

[lukemc]

i always play with a high master volume but to my ears as soon as i switch over to HDR even if i match the gain levels to what i had in LDR it just seems to lose a Certain TONE characteristic i love about the LDR.

IMO i think if some of the greats used this amp back in the Day 90% would use the LDR cranked.
clapton,kossoff,page,townshend,angus/malcolm young etc.

i Do love this amp.

[Mats A]

Ok i have a 1959 type plexi with EL34´s. The JTM have almost the same preamp as the 1959 excpt for a slight difference in the tonestack and maybe some other minor things. It also have a valve rectifier and hasn´t it got 6L6 valves? Might be wrong on this but was the JTM45 ever a plexi? It must have been discontinued in ´65 or`66.
On my VM 50W there is very little distortion even with the body and detail on full when it´s dimed. I play a Les Paul wich is quite powerfull also.

[lukemc]

as far as i know the JTM45 was the ORIGINAL plexi.
think they still made them in 67 maybe into 68. they use KT66's.

what do you mean by Very little distortion? would you be able to compare it to a certain famous recorded tone so i can get an idea of what you mean?

maybe you just love more overdrive and i love less.

[MKB]

Ok i have a 1959 type plexi with EL34´s. The JTM have almost the same preamp as the 1959 excpt for a slight difference in the tonestack and maybe some other minor things. It also have a valve rectifier and hasn´t it got 6L6 valves? Might be wrong on this but was the JTM45 ever a plexi? It must have been discontinued in ´65 or`66.
On my VM 50W there is very little distortion even with the body and detail on full when it´s dimed. I play a Les Paul wich is quite powerfull also.

Different 1959's have significantly different amounts of gain, mainly due to whether a capacitor across the cathode resistor of the V2 voltage gain side is there or not. The earliest 1959's had this cap, but then it was removed for many years until certain reissues came out with them in the late 1990's. EVH's "Plexi" is supposed to have a cap installed in that position, one of the reasons his amp had so much gain.

The preamp in the VM (except for the power supply and a few other changes) is somewhat close to a 1959, but there are a few differences that tend to lower the gain. First, there is no bright cap across the bright channel volume pot (Detail). Also the mid boost circuit removes some gain unless it is switched in. Add a bright cap across VR2, switch the mid boost on, remove C7, and add a 0.1uF cap across R17 (the equivalent of the V2 cathode resistor), and the gain levels of a VM in LDR would be comparable to a "hot" 1959.

You could probably not tweak HDR to sound exactly like LDR, as there is a bit of tonal shaping in the boost stage.

[frank9310]

Ok i have a 1959 type plexi with EL34´s. The JTM have almost the same preamp as the 1959 excpt for a slight difference in the tonestack and maybe some other minor things. It also have a valve rectifier and hasn´t it got 6L6 valves? Might be wrong on this but was the JTM45 ever a plexi? It must have been discontinued in ´65 or`66.

Mats the JTM45 was the first Plexi and it used(s) KT66 tubes and has a GZ34 tube rectifier, while the later Plexi's starting with the JTM100s began using a solid state rectifier in 1965 such as the one Jimi used later being the JTM45/100 with a single output transformer. This was because GZ34s were expensive and too mushy sounding with 100 watts of power vs the JTM45 which was only around 32 watts.

On my VM 50W there is very little distortion even with the body and detail on full when it´s dimed. I play a Les Paul wich is quite powerfull also.

Are you sure the amp is biased correctly? You should be getting a kick ass amount of crunch with a Les Paul and detail dimed. The amp comes to life when the master is set on around 8. If that's too loud for you to deal with, get a Marshall Power Brake or similar attenuator. Also, try a higher gain preamp tube in V1. JJ makes a higher gain ECC83s that Eurotubes sells. Have you seen the VM demo with a LP? Does yours get this much crunch? http://marshallamps.com/marshall_theatr ... at=VM_demo

Different 1959's have significantly different amounts of gain, mainly due to whether a capacitor across the cathode resistor of the V2 voltage gain side is there or not. The earliest 1959's had this cap, but then it was removed for many years until certain reissues came out with them in the late 1990's. EVH's "Plexi" is supposed to have a cap installed in that position, one of the reasons his amp had so much gain.

The preamp in the VM (except for the power supply and a few other changes) is somewhat close to a 1959, but there are a few differences that tend to lower the gain. First, there is no bright cap across the bright channel volume pot (Detail). Also the mid boost circuit removes some gain unless it is switched in. Add a bright cap across VR2, switch the mid boost on, remove C7, and add a 0.1uF cap across R17 (the equivalent of the V2 cathode resistor), and the gain levels of a VM in LDR would be comparable to a "hot" 1959.

You could probably not tweak HDR to sound exactly like LDR, as there is a bit of tonal shaping in the boost stage.

Good to know. Makes sense as I really notice a measurable increase in sustain with the mid boost pushed in but also a loss in highs so as much as I love the extra sustain and added warmth, I sometimes need to disengage it to cut through the mix a little brighter. In fact, when I have it engaged, my bass player tells me I'm competing too much with his bass tone and asks me to turn it off or boost the treble.

[Mats A]

Think my Bias is OK and I´ve played on other VM´s. Still the distortion Chris gets on LDR is less than on my 1959 Dimed with the PB that I got. Tried my VM on full both with and without it.

Also on the first VM demo where Chris played with his band he had a Duncan JB in the bridge position and I guess he had quite a hot pickup on this guitar also. Hotter than my PAF´s anyway.

[frank9310]

Hmm. I'll bet you don't get near the lead note definition though with the 1959 dimed as you get with the VM do you?

See that's why I like to run 2 amps. I run my VM with a Plexi clone. Gives me the fat singing leads with the brighter, glassier crunch of the Plexi which really gives that big sound all around.

[Mats A]

When I compare them the VM is a bit brighter more open sounding. More bluesy but fatter with the mid boost on. Without mid boost it almost sounds a bit mid scooped compared to the plexi. A little more Fenderish maybe. The plexi reissue seems more compressed in it´s tone.

[frank9310]

Wow. That's completely different from everything I know about Plexis as compared to the VM. For example, when I listen to Robin Trower's videos or audio clips from 2006 where he's using a Plexi JMP and a JCM 800, his tone is super bright and glassy and the 800 just added the extra crunch, but now that he's using the VM his tone is much warmer and subdued.

[Mats A]

Robin Trower is playing a strat wich is very different sounding to a Les Paul. Doesn´t he use some kind of overdrive pedal. It also depends very much on how you adjust the plexi. The VM has body and detail the plexi only one volume control. Seems from what I´ve heard that Trower has a rather clean sound on his amps. If you set the plexi at a low volume you get a much treblier sound than when you cranck it.

-- Sat Jul 10, 2010 4:48 am --

Maybe it is that you use a master volume on the VM. My plexi has a PPIMV wich I seldom use. I use the Marshall Power Brake instead. And the plexi sounds treblier not as fat using it with the master turned down.

-- Sat Jul 10, 2010 10:01 am --

I wonder if you can distort the outputstage as much on a VM as on a 1959/1987 amp regarding it has an effects loop and high gain. From the amps I´ve played it seems that high gain amps seems kind of designed not to distort as much from the outputstage since it probably would be overkill and not sound good with all the gain on tap.

[frank9310]

Have you tried diming the body and detail controls both on the VM? When I dime body, my Strat gets a lot of crunch.

Trower does use overdrive pedals yes but he uses them whether he's playing through an 800, 900, Plexi or VM. His playing is far from clean but he mostly relies on tube overdrive from his amps being cranked... Listen to this

[youtube][/youtube]