Let's talk about my Marshall

Discussion in 'Let's Talk Vintage' started by Travis398, Jan 9, 2020.

  1. Travis398

    Travis398 Well-Known Member

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    This is my first Marshall. A 50 watt head I bought back in 85 +/- I remember the day well. I was so excited to play my first Marshall. I carried it into the jam room placed it on a 4x12, plugged it in, turned it on and 10 seconds later the magic smoke came out the back of the amp.

    After bringing it to a Tec I got the story of loose tube sockets and blown transformers.
    I was a kid and knew nothing, but I knew it had to be fixed, I said go ahead.

    The Tec guy says these amps run hot you should get a fan installed in the side of the cabinet.
    So I say okay.

    Then the Tec asks Do you want the EVH mod? Duh? It's early 80's doesn't every kid want the EVH mod? So I say okay.

    The problem is I don't know what this mod did and I never ended up using it. There is a knob on the back that I pull out and turn it up or down and is supposed to do something But I never noticed much difference.

    If it were today I wouldn't have paid for that or the fan installed in the side of the head that I never used anyways. live and learn, right?

    Anyways after that this amp has been rock solid, I never so much as changed a tube
    or looked under the hood. It's been perfect.

    The power cord finally came to it's end, so I am going to cut a big hole in the back to put a modern day plug in and may want some advice in disconnecting this EVH mod. I will post pictures when the time comes. Till then, why is this head so small? was this intended for 4x10 cabinet? you wouldn't call this a Plexi would you? Is it JMP even though it don't say JMP?
    is this a 1987 model?

    I wasn't sure if this is considered "Vintage" But after looking around I think I'm safe.





    marshall.jpg
     
    Last edited: Jan 12, 2020
  2. houseofrock

    houseofrock Well-Known Member

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    There is a 50 watt version with a smaller head cabinet. All is good. You may want to post some gut shots of the mod so someone can help diagnose it. As for the cord, I would just replace the cord with a similar one for now. I get why you want to use a plug in. I just don't like the idea of cutting holes in the chassis.
     
    Last edited: Jan 9, 2020
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  3. Valvelust

    Valvelust Well-Known Member

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    :photos: of internals and back. If it's a 50 watter it's a 1987 smallbox.
    Some showed a JMP others no logo. Is that a MV installed in the Polarity switch hole?

    That's around the time I bought my first Marshall and 4X12. 1992 Superbass with a PPIMV with the potentiometer coming out of one of the imput jack holes. It also went up in smoke in the early 90s and never had it fixed but still have it.

    A plexi has plexiglass front and rear panels, last ones made I believe were 1969 other than re-issues. Also the serial number will depict the age.

    Here's a little about his mods.
    http://wwwc.dcns.ne.jp/~epi/witnesses.html
     
    Last edited: Jan 10, 2020
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  4. neikeel

    neikeel Well-Known Member

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    So probably made between mid 69 and 71.
    Pictures of good, bad and (if necessary) ugly will be great help.
     
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  5. Travis398

    Travis398 Well-Known Member

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    Yes it is a 50 watt. I thought it was a 1987 but I wasn't confident enough to bet on it. There is no JMP logo visible.

    Yes that is a master volume in the polarity switch, that was there when I got the amp and I didn't know it was a mod till a few years later when I learned what the polarity switch was. It always worked well but the amp seemed confusing with 4 volumes. Probably why I never used the Mod.

    I don't call this a Plexi and it does have an upright transformer, I thought Plexi has the lay down tranny and plexiglass front and back.

    I have seen people calling these Amps Plexi and listing them for sale that way, so I just wanted to make sure no Plexi

    Thanks for the link, I didn't realize there was that much modding linked to EVH. I thought the Tec guy was feeding me a line of crap and just used Eddies name to make the sale.

    I can say this amp does not have high gain and maybe that is what I thought I was going to get when I got the amp modded. I ended up using a dirt pedal to get me by

    I'll get Pic of the back tomorrow
     
  6. Travis398

    Travis398 Well-Known Member

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    Nailed it!

    How did you know? did they stop the small heads in 71? did they make 100 watt small box?
    according to the serial number it's 69'

    Yes I am worried the pics may be ugly
     
  7. Valvelust

    Valvelust Well-Known Member

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    No 100 watt small box, the chassis to incorporate 4 tubes is to large.
    Yes could be a lot of "cobb" in the works, hopefully not. There were many different ways people tried to make the "brown sound" some without much real knowledge and mess up a lot of circuitry. Eddie used a variac for a short period setting to 93v or so as well to aid he affliction... ;)
     
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  8. Matthews Guitars

    Matthews Guitars Well-Known Member

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    Post a pic of the back of the amp with the cover taken off.

    If it has two power tubes it's a 50 watter and the chassis will be 17 inches wide.

    If it's a '69 by the serial number, it's worth restoring to its original state, for sure. Fortunately it looks like the added "features" were added to existing holes,
    so there's no extra holes drilled in the chassis. (From the front, anyway.)

    I would NOT recommend carving a big hole in the back of the chassis to install a power plug IEC socket. Just have the original power cord replaced by a technician who has the proper Heyco grommet installation/removal tool.

    No, they're not high gain amps. Just about every great "plexi" Marshall tone from all the 80s metal bands was achieved with some combination of heavy mods to the amp and overdrive/distortion pedals.
     
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  9. Travis398

    Travis398 Well-Known Member

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    It's a 50 watt. The back knob is installed where a voltage selector should go next to speaker impedance, looks like the amp didn't come with one so the Tec may have drilled a hole for the pot?
     
  10. neikeel

    neikeel Well-Known Member

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    That does not sound too bad, shame about the fan hole. They don’t normally run that hot and back panel off usually suffices, but it might be hotter where you live.
    Would be interesting to see what transformers were used.
     
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  11. Travis398

    Travis398 Well-Known Member

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    The speaker selector was put in when the mod happened. Looks like someone changed the power cord before me. It's all scratched up from pliers or screwdriver and the tin is bent pretty good, looks better in the picture.

    as far as the power cord its function over form. Always having the cord in the way is a pain.
    or tripping over it while carrying the amp, or its tucked in the handle making it harder to pick up. All my other Amps have the standard cable and it makes everything so easy to unplug move or swap and replacing a damaged cord is easy too.

    As far as value is concerned this amp won't be worth much when the time comes to say good bye.
    I have owned it for many years and don't plan on getting rid of it. So when I pass thousands of other guys just like me are going to pass. And all of them old amps being hoarded are going to flood the market. The next Gen won't be interested in these, They will all be using their Cell phones with a kemper app.

    I could be wrong, time will tell.

    I'll try to get the back cover off and get a pic soon, I just got a new guitar so I have been distracted with that lately


    back.jpg
     
  12. TAZIN

    TAZIN Active Member

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    As mentioned by others, it's a 50 watt probably built in the second half of December 1969.
     
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  13. Travis398

    Travis398 Well-Known Member

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  14. Travis398

    Travis398 Well-Known Member

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    Looks like the output and power transformers are drake, the choke is probably original.

    Looks like 6550 tubes, I thought it had el34s obviously not.

    20200112_124619.jpg
     
  15. Travis398

    Travis398 Well-Known Member

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    not sure what happened here but I am guessing that's not professional workmanship?


    20200112_124402.jpg
     
  16. Valvelust

    Valvelust Well-Known Member

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    Tip it over let's see inside
     
  17. Travis398

    Travis398 Well-Known Member

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  18. Travis398

    Travis398 Well-Known Member

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  19. Ned B

    Ned B Active Member

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    The power trans appears to replaced with a 1202-324 which followed the 1202-164.
     
  20. Trapland

    Trapland Well-Known Member

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    Edit: I didn’t see that you had a cord through. I thought it would be a bulgin. Never mind and hack away.
     
    Last edited: Jan 13, 2020

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