Marshall 1959 Plexi vs. JCM 800

Discussion in 'Marshall Amps' started by jakethecracker95, Dec 28, 2008.

  1. jakethecracker95

    jakethecracker95 New Member

    Joined:
    Dec 27, 2008
    Messages:
    10
    Likes Received:
    0
    I was just wondering what would get a more versitale sound and if the plexi would get as much gain as the JCM 800, even with a cascade. I really don't know much about amps, so it would be nice if someone could reply quickly
     
  2. Brett Blackmore

    Brett Blackmore New Member

    Joined:
    Apr 16, 2008
    Messages:
    481
    Likes Received:
    45
    Location:
    Bingen, Germany
    The JCM800 has a plexi heart yet has a master volume to give you some gain sounds at lower level. The amount of gain is good enough for most pop & rock rhythm sounds - it is smooth/controlled and sounds good. If you want more then you need an o/d pedal or a preamp. This is the amp which I would choose as it has more possibilities.

    The Plexi has no master volume so there are no gain sounds until you crank it up VERY loud - and then there are serious issues as it is no good for most pop & rock rhythm sounds as it is bleeding uncontrollably - and bleeding loud! (A power attenuator is necessary to drop the volume - but it might go muddy...). If you want more controlled gain then you need an o/d pedal or preamp to smooth it out - so why not take a JCM800 which are usually cheaper?). But again, the sound is for a selective audience and a selective music..

    The good thing about a Plexi is its unique sound between stages - when 1) clean, 2 ) crunch and 3) overdriven - which means a Plexi sound is still the most desired sound for blues purists - it also incorporates the traditional approach to overdriving an amp. The bad thing is that it can time a long time before you find your sound right as you need to mix&match pedals.

    I would recommend a 'Vintage Modern' which I hear can do both worlds to most people's satisfaction.

    Cheers Brett
     
  3. HOT TUBES 70

    HOT TUBES 70 Well-Known Member

    Joined:
    Oct 13, 2008
    Messages:
    10,831
    Likes Received:
    5,110
    Location:
    The frozen hell called Canada !
    +1 as a rule the 800 will have a lot more gain etc.
     
  4. tazzboy

    tazzboy Well-Known Member

    Joined:
    Oct 1, 2007
    Messages:
    893
    Likes Received:
    302
    Location:
    Oregon
    I wonder where a JTM 45 100 watt would rank gain wise?
     
  5. HOT TUBES 70

    HOT TUBES 70 Well-Known Member

    Joined:
    Oct 13, 2008
    Messages:
    10,831
    Likes Received:
    5,110
    Location:
    The frozen hell called Canada !
    a jtm could never hang with a 800 , again different animal.
     
  6. Lensman

    Lensman New Member

    Joined:
    Dec 29, 2008
    Messages:
    1
    Likes Received:
    0
    Hi guys,

    I'm new here... virgin post lol.

    The jtm 45 100 is by far the best Marshall i've ever owned. Not as loud as a Super lead. Can get pretty nasty at high settings. Not jcm nasty.. That's where the jcm's shine.
     
  7. tazzboy

    tazzboy Well-Known Member

    Joined:
    Oct 1, 2007
    Messages:
    893
    Likes Received:
    302
    Location:
    Oregon
    Acutally the one plexi that I have heard that can a do good distortion is the 1959 SLP-XL and 1987-XL cause they were made between 1966 to 1968
     
  8. HOT TUBES 70

    HOT TUBES 70 Well-Known Member

    Joined:
    Oct 13, 2008
    Messages:
    10,831
    Likes Received:
    5,110
    Location:
    The frozen hell called Canada !
    In the same league as a 800 ?, most 800 series amps would alot more
    gain on tap , remember the 80's was all about the thick ,fat distortions.
    i have played on a 1959 (but not a xL) and it was great classic tones
    but not the gains of the 800 amps , i wonder what difference is between
    a SLP and a SLP XL ????

    anyone???
     
  9. tazzboy

    tazzboy Well-Known Member

    Joined:
    Oct 1, 2007
    Messages:
    893
    Likes Received:
    302
    Location:
    Oregon
    SLP XL Think Early Van Halen Tone and ZZ Top. This was when the it was going Bassman Circuity to Super Lead Circuity. Kind of a mixture of both if you know what I mean.

    Here is 1987-X at Pro Guitar Shop Demo. YouTube - Marshall Plexi 1987x
     
  10. plexipaul

    plexipaul Active Member

    Joined:
    Jun 11, 2008
    Messages:
    152
    Likes Received:
    57
    Location:
    deep south in the lowlands
    The negative feedback resistor and the output tap it is connected to determines the amount of out-of-phase signal fed back into the phase inverter. The higher the value of the resistor, and the lower ohm output tap it's connected to, the less negative feedback and hence more power amp distortion.

    While the changes in the NFB (negative feedback) arrangement seems to be somewhat inconsistent and varies a bit with the model (50 vs 100, lead vs bass), in general the timeline is something like this:
    1966-67: 27k resistor @ 16 ohm or 8 ohm tap
    1968-69: 47k resistor @ 8 ohm tap
    1970 onwards: 100k resistor @ 4 ohm tap


    The other two factors, which do actually affect preamp gain, are:

    1) The presence of a split cathode arrangement on V1. This appeared on the Lead model amps only from around mid-68 or so. Bass models or PA models did not have this. Tremolo models sometimes did, sometimes didn't.

    2) The presence of a capacitor on the V2 cathode, usually of 0.68uF value. These seem to be most prevalent around 1969, by sometime in 1970 it's rare to see them. This bypass capacitor, which does give a bit of a mid boost, also only appeared on the Lead model amps (and possibly some tremolo amps).

    There are other minute variations, such as 0.022 vs 0.0022 first stage cathode coupler in the split cathode Lead amps, of which the first one is definitely rarer, but gainier, and only used in the earliest split cathode Lead amps. In general though, I'd say the above factors are the most important in determining the overall gain in that era of Marshall amps.

    So in theory, the *most* gainy amp is actually a 1969 or 1970 Super Lead with split cathode, 100k@4 ohm NFB and V2 .68uF bypass cap.

    Since Marshall left the plexipanel somewhere in `69 you can say that the gainiest plexies (stock) are from `68-`69 era (like Eddie Van Halen`s famous amp). These plexies (JMPs) rule the JCMs.



    Marshall 1959 Plexi vs. JCM 800 ? Which JCM800 model?
    If Jake refers to JCM800 1959 model (NMV) the difference is for the most part cosmetical. If not it`s comparing apples and oranges, NMV vs. MV models.
     
  11. Jimbo

    Jimbo New Member

    Joined:
    Jun 4, 2010
    Messages:
    13
    Likes Received:
    5
    Hi fellow marshall hounds,

    I have both an early 1969 year model 50 watt plexi faced model 1987 and a 1981 JCM800 model 2204 MV.

    I love both amps for different reasons. I use the Plexi with marshall powerbrake which suprisingly does not go muddy so it retains the "bright crunch" most plexi's are known for. It is really addictive. It can be played nice and clean when played softly, then you dig in and it cries sweetly or crunches bricks. It has a distinctive raspier (some call it rawer)sound when cruching. I believe this was much of Ken Fischers inspiration for the trainwrecks. Maybe not circuitwise, but similar performance. It was seriously worth every penny. I use greenbacks to get the classic plexi sound.

    The first year JCM 800 is very plexi like with some very distinct performance differences. When using the high gain input, it has lots more pre-amp gain for 80's rock and metal sounds. By using both masterV and pre-amp volumes you can go from marshall clean to plexi-like gain to hot-rodded plexi type gain. The newer vintage-modern's are designed for pretty much the same thing. I used the 6550 power tubes for a long time but got tired of the narrowed range of tonal possibilities limited by the dreaded high frequencies associated with them. I recently installed a NOS set of 6ca7 big bottle "Fat Boys" which give a hybrid EL-34 sounds which I like. The bottom on the JCM 800 got fatter with the 6ca7 tubes. Since I use EVM12L's with it, the tonal range is damn good, huge bottom and ear peircing highs too.

    If I did not already have the plexi, knowing what I know now, I would get the JCM 800. It is certainly more affordable and available. Might also consider a Vintage-Modern...:hmm:
     
  12. DPTONE5

    DPTONE5 Well-Known Member

    Joined:
    Jan 31, 2010
    Messages:
    4,361
    Likes Received:
    2,549
    Location:
    Pennsylvania
    +10000 Jimbo....

    I too own a 1987XL and a 1980 JMP-2204 (vertical inputs - from what I understand, the same amp as a 1981 JCM-800). The 1987XL has absolutely GREAT tone for recording. I believe it is more articulate and thicker than the JMP. But with an attenuator, it does lose some of it's tone. It's great having the Master Volume JMP so I don't lose my hearing and upset the family!

    The JMP has a more gain, especially when driven with a pedal. For cleans, the 1987XL is much better, especially with the strat.

    If I owned one, I'd probably go with the JMP or JCM-800.

    I also own a 6100. IMHO, it covers both amps really well and it has a master volume. Something to consider.....
     
  13. Michael1987xl

    Michael1987xl New Member

    Joined:
    Dec 20, 2009
    Messages:
    852
    Likes Received:
    153
    Location:
    New Jersey
    Change the 1987xl over to KT77's and that "attenuator tone loss problem" becomes a thing of the past. Best "modification" I've ever done, hands down.
     
  14. Jimbo

    Jimbo New Member

    Joined:
    Jun 4, 2010
    Messages:
    13
    Likes Received:
    5
    You know, I have never used any of the KT (Kinkless Tetrode) series tubes so I do not know what you get from them. In the future, I plan to get a set of KT's for the JCM 800...

    In my Plexi, I did remove the original "British Mullards" to try out the Groove Tubes EL-34M, a supposed copy of the famous Mullard XF-2 (Dual Getter). I have to say that I am impressed with them because this set has performed very closely to the British tubes. I bought the Grade 5 rated EL-34M's which turned out to be the right call as they are very difficult to distinguish from the originals that were installed in the amp back in 1969.

    I have tried the Svetlanas, Wing-C's, Chinese EL-34B, JJ E34L, Groove Tube E34LS, Old Tesla military tubes (brown and black bases), Seimens, original XF-2 Mullards, US made 6CA7 and the closest to the old Mullards has been the EL-34M (Old Tesla's were second). The grade 5 seemed to retain the "HI-FI" qualities of the original Mullards for the more softly played parts but also retains the overdriven crunchiness when you change to more aggressive pick attack. Many just want all out crunch but I like the HI-FI quality too. If you watch the "Trainwreck" demo's on YOUTUBE you will hear the incredible transitions from clear Hi-Fi sounding cleans to screaming, weeping roar with a change in pick attack.

    I can now save the original Mullards for "Sonic Reference" to demonstrate the "Historical Sound" and keep playing the classic marshall tone on the newer tubes. From what I hear about KT's, they may be very similar.
     

Share This Page