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What was it? Marshall 50 w bass head, late 1960s

Discussion in 'Amps and Cabs [BG]' started by AdamF, Jul 13, 2005.


  1. When I first started playing bass in the late 1960s I had a Hofner semi-acoustic, a VOX AC30 and a Marshall 50 w head - which I think was a bass amp. Of course, I sold it. Would anybody out there care to point me to where i can found out, or even better what that Marshall actually was?
    Thanks
    Adam
     
  2. DaveMcLain

    DaveMcLain

    Jun 19, 2005
    Cuba MO
    Marshall "bass" amps from that era are almost identical to the guitar or PA versions. They can easily be converted from one spec to the other in fact, the US distributor did this very often if it was short of one type of the other, I've got two old Marshalls and both of them were converted from bass to lead sometime in their life.

    So, if you find an old 4 input style 50 watt top you can make the bass amp by changing the slope resistor on the tone controls and the value of two coupling caps in the output section, very easy.

    My recomendation would be to try playing bass through the guitar version, you might like that sound better, but to be honest there is very little difference...
     
  3. I also had one. My Bassman didn't seem to have enough power, so I sold it in favour of a Marshall. The Marshall was great if you wanted the thumpy and distorted Jack Bruce sound that was so popular back then, but it was not capable of producing anything sounding even remotely like a Bassman (despite being loosely based on the Fender design).

    The model number was simply JMP50. I later discovered that I had a JMP100 despite what was written on the amp itself. The earliest JMP100 models had JMP50 panels on them. The way to determine the difference was to count the power tubes: 2 (JMP50) versus 4 (JMP100). Today this amp is referred to as "plexi", due to the plexiglass panels. It has always been my understanding that the bass and lead models were essentially the same... (see Dave's post above).
     
  4. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD
    I really want a JTM45-100 or similar.....
     
  5. It's funny that it never occurred to me at the time. The Marshall seemed so very "english" with the controls seemingly all backwards, at least if you were used to a Bassman. You felt like you should be driving on the other side of the road.

    Really it was (essentially) the same layout turned upside down... panel at the bottom with the tubes and transformers pointing up, but a reasonable facsimile of the Bassman in many regards.
     
  6. Arthur U. Poon

    Arthur U. Poon

    Jan 30, 2004
    SLC, Utah -USA-
    Endorsing Artist: Mike Lull Custom Basses
    Cool thread. I've been trying to find information on which model(s) of Marshall heads Bruce, Entwistle, Redding, etc. used back in the day.

    If anyone knows of a site where I can find more info, I'd appreciate it. Same for info on the HiWatt heads that John Wetton used while he was a member of King Crimson.

    Thanks, - Art
     
  7. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    ooo... The Starless & Bible Black tour ... I can't for the life of me remember Wetton's rig. I was blown away though. I always thought Wetton was highly underrated. His lies might not have been as advanced as some, but he was an awsome singer and hell - that's a great trick!
     
  8. anyonefortennis

    anyonefortennis Supporting Member

    Jun 28, 2005
    Lincoln, NE
  9. Maybe this will help jog your memory... great tour! Sometimes he sounded like he was driving a Euclid (maker of big friggin' trucks and tractors) across the stage!

    Ooops. My bad. Seemed that the pic linked to Tripe-odd. Sorry about that. Anyhow, there are some easily-found pics out there.

    One of the articles on Robert Fripp mentioned that John changed over to Cerwin Vega cabs at some point and that they sounded unbelievable.

    I switched from the Marshall to a Hiwatt DR-103 and it was a sweet amp, but like so many others I REALLY wanted a DR-405!
     
  10. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The original Marshall was a copy of the '59 Bassman 4x10 combo, not the more familiar '61-'70 Bassman 2x12/head. Marshall copied the '59 because he didn't know enough about amps to try and copy anything more sophisticated. He was, after all, only a drummer. The '59 Fender in turn was a copy of a Western Electric amp which had been in the public domain and thus Leo didn't have to pay royalties on.
     
  11. Ben Clarke

    Ben Clarke Liquidating to fund a new business. Buy My Gear!

    Jan 6, 2005
    Western NY
    Familiar story, Bill. The Ampeg B-15 powerplant was apparently straight out of the RCA tube manual.
     
  12. Now I know what I sold! Some years later I also owned a Gibson EB3, which I also sold. Rats.
    Adam
     
  13. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD

    VERY nice!!! I'll look into these.

    I still want a Hiwatt though as well. I've got a friend moving to England for a year this weekend, so he's gonna scout out some vintage British amps for me. :cool:
     
  14. DaveMcLain

    DaveMcLain

    Jun 19, 2005
    Cuba MO
    Personally, I think a HiWatt top would be a much better amp for bass than a Marshall. I've got a Hiwatt DR504 50watt top and it's a VERY impressive amp, awesomely loud and easily the loudest and most aggressive sounding 50watt amp I've ever heard. As you know, Hiwatt made 200watt and 400 watt versions of their amps but they are pretty rare. I've heard that the 200's are very hard on tubes (6 EL34's) but I'm not sure about the 400's with KT88's. My 50 watter is rough on EL34's too, they just don't hold up very long in that amp, but it's a small price to pay. Our guitarist Robby uses it once in a while if we've got a big outdoor show to play, like this Friday with the Spin Doctors, sounds fantastic.