tell me it aint true PLEXI 5 GRAND

Discussion in 'Let's Talk Vintage' started by Exotic, Apr 17, 2020.

  1. Exotic

    Exotic Well-Known Member

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  2. ampmadscientist

    ampmadscientist Well-Known Member

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  3. South Park

    South Park Well-Known Member

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    Looks like a hack job . No gut pics . Who did the mods . What repair work was done . I really like that rustic look
     
  4. Ken Underwood

    Ken Underwood Well-Known Member VIP Member

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    With rust patches on an Alli chassis, now way
     
  5. Marshallhead

    Marshallhead Well-Known Member

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    The chassis is steel.
     
  6. neikeel

    neikeel Well-Known Member

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    Ok, here goes.....
    [​IMG]
    It is typical late 67 - early 68.
    Steel chassis of the JMP (not JTM) era.
    Started off life as either a 1985 PA, 1986 Bass or 1989 Organ model presently half converted to lead spec (preamp only)
    V1a cathode cap and resistor replaced - messily
    Added V1b cathode and cap mod to make it spilt cathode
    V1a coupling cap non-original replacement (should be 22nF mustard)
    V1b mustard is a salvage part (see grafted leads)
    Piggy backed bypass caps on the lead mixer channel
    Modern silver mica treble cap
    Replaced v1 plate and V2a cathode follower 100k resistors with cheaper type modern carbon comps
    Original 56k slope resistor replaced with 33k (as per lead spec) looks like an AB
    Burned (original) 10k carbon comp preamp dropper
    Removed (gone!) preamp filter cap (normally dual 32uF 350v type)
    Swapped pi input coupler (should be 22nF mustard)
    Replaced standby swiich

    Positive things:
    Original undrilled chassis and panels with serial intact
    Original OT, PT and choke
    Board is repairable and output section original
    All controls, jacks and wiring look unmolested
    Added screen resistors, modern bias caps and bias adjuster the filter caps look to be modern, no name cans - all ok but not ideal for top dollar.

    I have one here that I will post pics of later - slightly different
    For $200 that particular amp above could be transformed into something worth approaching the asking price.
     
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  7. neikeel

    neikeel Well-Known Member

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    Oh and he has a trem of same era with same high qulaity signature tech work (sic.) replaced but correct OT (minus its trem board) with, sadly some extra ventilation:
    [​IMG]
    [​IMG]

    Maybe Billy Blades granpa's work?
     
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  8. Ken Underwood

    Ken Underwood Well-Known Member VIP Member

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    To me original is Aloy, 68 is 5 years on.
     
  9. Seanxk

    Seanxk Well-Known Member

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    On corrosion/Oxidation, I think the term rust is for Iron based materials like steel, all other metals when corroding Oxidize.
     
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  10. neikeel

    neikeel Well-Known Member

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    They phased out aluminium alloy (Ken did you get yours from Smiths Industries supplier on TCR?) in late 66. The ones that were originally used bent and flexed from the trasnformers with roadies chucking stuff in and out of vans. I've got a 65 100w PA here somewhere with added wooden blocks! The factory tried to beef the aluminium up with cast aluminium end blocks for late 66 but by Feb 67 the steel chassis were introduced. Initially with the dull grey plating finish. The zinc chromate (passivated) ones came in around 1971 (AFAIK).
     
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  11. Seanxk

    Seanxk Well-Known Member

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    The dull grey is most likely Cadmium plated, which was the norm then, but still expensive compared to Zinc plating and as we know today highly carcinogenic.
     
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  12. Ken Underwood

    Ken Underwood Well-Known Member VIP Member

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    The original chassis were produced by a local engineering workshop, one that Ken Bran knew about.

    I take it you were around at that time in London??
     
  13. neikeel

    neikeel Well-Known Member

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    I had just been born, which is why I ask in particular about your experience of getting the parts together.
    I am, however, familiar with the old (and mostly long gone) electronics shops at top end of Tottenham Court Rd.
     
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  14. Ken Underwood

    Ken Underwood Well-Known Member VIP Member

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    Well thats was most if not all the came from initially, sad you were not there to see it as it was quite magical with give away prices.

    Many pieces of ex-military equipment still in its original packing cases never been open and all types of components all still wrapped in there wax paper.

    Not only Tottenham Court Road but Edgware Road and the most important one was Lisle Street in Soho.

    This was dream heaven for anyone like me starting out in the electronics trade.

    As a 16 year old could often bee seen carrying all sorts of kit, one in particular a 3ft square wooden packing case with rope handles on the underground train, then on a bus back to Hayes.

    That was a Canadian Marconi 52 set, short wave radio receiver, made with a steel case, could not do it today lol.

    Just a little insight on how things were back then, shame you could not have seen it, and just a bit about how Marshall was set up from day one.
     
    Last edited: Apr 28, 2020
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  15. pleximaster

    pleximaster Well-Known Member

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    Thanks a lot Ken for this story! This is the kind of stories I love to hear you tell!

    Best regards plexi
     
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  16. Ned B

    Ned B Active Member

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    When I was first in London in the mid 70s I bought a UK to US step down transformer in Tin Pan Alley. I had brought a brown Fender Super to play and this allowed me to play it there.

    On this plexi I agree with Neil that it's not that bad and very salvageable. If you keep an inventory of Piher, Iskra & mustards the board is no problem and it has all the harder to get important bits like transformers. In my opinion this is a $3000 amp in this market. Even in a frothy market it wouldn't make the 5K. I check Ebay every day and I get wiry of the dangled pieces up for month after month.

    It is interesting that the same seller has had this one up for a long time at $3750 with OBO and this one is in pretty comparable condition which may support my opinion.

    https://www.ebay.com/itm/1968-Marsh...774604?hash=item2adb88618c:g:jnQAAOSwCOhd6anu
     
  17. TM1

    TM1 Member

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    $5K? Well of course it is.. A Pawn shop is selling it and they almost always ask too much for anything.
     
  18. purpleplexi

    purpleplexi Well-Known Member

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    Tottenham Court Rd was mecca to me and my guitar playing buddy back in the early 70s. Hanging round Sound City and all the other shops trying stuff we couldn't afford. I remember once we sat in the Fender Sound House and my friend tried every guitar n the place. The salesman was getting really antsy with us 2 kids mucking about with all their stuff. In the end we asked him what the most expensive guitar in the shop was and he showed us a Fender Starcaster which he said was the first one in the country. My friend played it for a few minutes and said 'Ok I'll take it'. The guys jaw dropped when My friend pulled about £600 in pound notes out of his pocket and handed it over. That was the price of a decent used car then.
     
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  19. Crikey

    Crikey Well-Known Member

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    Frickin love it!! That's a great story. I bet they never second guessed a kid coming in the shop again.
     
  20. jstich

    jstich Well-Known Member

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    I'd maybe buy something in a pawnshop for a few hundred but 5 grand?! No way in hell.Some pawn shop owners are dirtbags.
     

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