DSL40CR bright cap?

Discussion in 'The Workbench' started by tmingle, Nov 27, 2021.

  1. tmingle

    tmingle Well-Known Member

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    Does the 40CR have a bright cap installed on either channel?
     
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  2. gregr

    gregr Well-Known Member

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    Classic yes (two separate values). Red no.

    My unsolicited opinion:
    Clean cap is just right.
    Crunch is a smidge too small.
    Ultra 1 and 2 would benefit from 220pF.
     
    Last edited: Nov 27, 2021
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  3. FracStrat

    FracStrat Well-Known Member Gold Supporting Member

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    Greg, Is C74 ready to receive should one decide to drop something in there ?
     
  4. gregr

    gregr Well-Known Member

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    It says it’s not fitted so it’s should be all ready to go.

    97976283-79E9-4CD2-910D-C3B27BB9CF07.jpeg

    Full disclosure:
    I don’t own this amp but I have played one. I do have a JCM2k DSL100 and with the same bright cap the behavior of the gain control will be the same. I use OD1 and like it on the aggressive side but I don’t use a whole lot of gain. I use an OD pedal to boost into saturation.
     
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  5. LCW

    LCW Well-Known Member

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    Play louder. :p
     
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  6. purpleplexi

    purpleplexi Well-Known Member

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    Not many complain about the CR being too bright once they get it dialled in. Depending on how old the amp is getting the speaker broken in makes a difference. I put different power tubes in (because I had them sitting around) which also improved things.
    Like I say the eq is sensitive. Half a gnats makes a big difference.

    That said if I could change the red channel and take some of the mud away (as indicated above) I'd prob consider it. For me the red isn't really usable.
     
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  7. tmingle

    tmingle Well-Known Member

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    Thanks guys. That explains a lot. Has anybody scored an official schematic for these yet? The clean sounds great on this amp, but I feel all the OD channels are lacking something.
    I do recall removing C19 from my 40C a while back & did not care for it at all. I did not try different values on the 40C though.
     
  8. gregr

    gregr Well-Known Member

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    https://www.marshallforum.com/threa...-dsl-schematics-are-finally-out-there.105345/

    Besides removing the bright cap, R101 and C75 are a bit of a departure from the original JCM2k DSL. Restoring these to the original voicing will make a marked difference, if you should ever want to go in this direction. The input impedance was basically cut in half as well.

    I annotated some of the important changes in another discussion. Maybe I can dig it up.
     
    Last edited: Nov 28, 2021
  9. gregr

    gregr Well-Known Member

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  10. tmingle

    tmingle Well-Known Member

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  11. SkyMonkey

    SkyMonkey Well-Known Member

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    Those (incomplete) schematics are all we have so far.
    They are from 2015 too. 3 years before the DSL40CR was released.
    So, prototypes at best.
     
  12. gregr

    gregr Well-Known Member

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    So is C74 populated on the amp in question?

    I’ve worked off the schematic for the DSL20H. There are indeed a few value changes and one area of cut & jumper rework, but the board layout still matches,
     

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