Revalved 1987x - what a difference

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newi123newi123 Frets: 678
So my early reissue 1987x has been playing up a little recently - dropped it to the tech for once over and PAT test. He said it was ok, but changed the master volume pot (he thinks added on the back by the factory as it`s really well done - did the factory offer this?) - and he`s revalved it all the way through.

Wow- what a difference! On the normal channel it is so much fuller and louder - like properly plexi loud again. Sounds ace.

I`d been eying a Tonemaster twin, but may be unnecessary now. 

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Comments

  • ICBMICBM Frets: 56948
    newi123 said:

    master volume pot (he thinks added on the back by the factory as it`s really well done - did the factory offer this?)
    No.

    What valves did he use, and what did it have before? Classic Marshall circuits like this need specific valves in the V2 (middle preamp valve) position or they tend to fail, one of the symptoms of which can be low volume and dull tone. Of the modern-production ones, only the Chinese Shuguangs (or relabelled ones) are suitable - easily identifiable by the two bright chrome strips on each side of the plate structure inside. Russian-made and JJ valves will usually work for a while but fail much sooner than the Chinese ones.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • hywelghywelg Frets: 3627
    Is this the position where a an old RFT works best John?
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  • newi123newi123 Frets: 678
    ICBM said:
    newi123 said:

    master volume pot (he thinks added on the back by the factory as it`s really well done - did the factory offer this?)
    No.

    What valves did he use, and what did it have before? Classic Marshall circuits like this need specific valves in the V2 (middle preamp valve) position or they tend to fail, one of the symptoms of which can be low volume and dull tone. Of the modern-production ones, only the Chinese Shuguangs (or relabelled ones) are suitable - easily identifiable by the two bright chrome strips on each side of the plate structure inside. Russian-made and JJ valves will usually work for a while but fail much sooner than the Chinese ones.
    Will need to ask - interested as didnt realise they were so sensitive to preamp valves. Thanks.

    It's running 5881s in the power amp.
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  • ICBMICBM Frets: 56948
    newi123 said:

    It's running 5881s in the power amp.
    Did it come like that - they made some with them in the mid-90s I think - or has it been converted? Either way they're not the right valves for the classic Marshall sound, it should have EL34s. 5881s would need a substantial rebias as well, usually outside the range of the trimmer so it would need to have had a resistor changed.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • newi123newi123 Frets: 678
    Think it came like that. Bought it from vintage & rare, they said the early ones came like this. That's certainly what was I  there. 

    I've always liked marshalls with 5881s / 6L6s. Had them in a jtm45 tok and that was fab.
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