So, Did We Ever Figure Out Why The Dsl20hr Has Only 3 Preamp Tubes?

Discussion in 'Marshall Amps' started by _ripper_, Nov 4, 2018.

  1. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    the point is the 5 watter uses a s/s staging, rather than all tube, like the 1 watt.
    5 stages & cathode = 6 tube functions. 3 tubes using each ½ per function = 6 functions.

    The lower watt amps are a hybrid. Apparently, they are using the s/s PI in both...
     
  2. _ripper_

    _ripper_ Well-Known Member

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    Forgive me if I'm not understanding something, but I'm asking about the 20 watter, which has one extra preamp tube compared to the 1 and 5 watt amps.
     
  3. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    from above:

    5 gain stages & cathode = 6 tube functions. 3 tubes using each ½ per function = 6 functions
     
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  4. _ripper_

    _ripper_ Well-Known Member

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    OK, I got it now :D Thanks for patiently explaining!

    So, taking that reasoning a step further and since the 1 and 5 watt amps have two preamp tubes vs three in the 20 watter, that means that the DSL1HR and DSL5CR amps also have SS gain stages, in addition to a solid state PI.
     
    Last edited: Nov 8, 2018
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  5. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    correct...
     
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  6. guitarman3001

    guitarman3001 Active Member

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    Here's the info I got directly from Marshall for the DSL20's tube layout.

    V1A input driver

    V1B OD gain stage

    V2A OD gain stage

    V2B Clean and OD gain stage, tone stack driver

    V3 Phase inverter
     
  7. _ripper_

    _ripper_ Well-Known Member

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    That makes sense, but it seems then that Marshall is telling you and @Delete!! two different things.
     
  8. guitarman3001

    guitarman3001 Active Member

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    When it comes to Marshall I would go with common sense over what a Marshall rep says.

    A rep on the my Marshall forum told someone the broken emulated out on his dsl20 is working as intended.
     
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  9. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    who from Marshall?
    all depends on who you are talking about...
     
  10. guitarman3001

    guitarman3001 Active Member

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    Not sure if I should post the name in public.
     
  11. Delete!!

    Delete!! Member

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    I agree, and to be honest I expected the responses in this thread to go this way (discrepancy’s between what Marshall is telling customers). That’s why I stand by my earlier statement, I base my likes/dislikes on tone alone. I like the tone of my 5CR, despite the solid state bits. It’s fun to try and figure out what’s going on design-wise in these amps, but at the end of the day all that matters is this - does it sound good to your ears?
     
  12. ampmadscientist

    ampmadscientist Well-Known Member

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    On the wrong side of the tracks.
    I guess 1 schematic is worth a thousand words.
    Anybody got a schematic?
    Until then...
    What I see is a tube phase inverter...and a SS effects loop.

    [​IMG]


    Most Marshall amps I have seen (including this one) are based on a certain form-factor which is:

    Plexi
    Preamp stage V1a
    Preamp stage V1b > mixer > saturation stage (V2)> Phase Inverter V3 > Power amp

    2203 / 04
    Preamp Stage V1a> Preamp Stage V1b > Saturation Stage (V2) > Phase Inverter V3> Power Amp
     
    Last edited: Nov 8, 2018
  13. stickyfinger

    stickyfinger Active Member

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    Deleted for misinformation
     
    Last edited: Nov 8, 2018
  14. stickyfinger

    stickyfinger Active Member

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    As far as I know the 2018 DSL series, 1R, 5R and 20R series are using a SS PI as told from Marshall. The 40/100 are using tube PI.


    The 2012 reissue series were all tube.
    The 5 and 15 had a different circuit ( no cathode follower TS ect) than the 40/100.
     
  15. Antmax

    Antmax Well-Known Member

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    That photo with DSL15M2 printed on the board is actually the DSL20 internals. Taken from the DSL20h gut shots thread of these forums.

    Here's the only pic I could find of the board reference number for the old DSL15.


    [​IMG]

    Unfortunately no one seems to have taken a zoomed out photo of the 15.


    OOH! Just did, and it's quite different. You can tell the other one is the 20 because there are no Bias Trim pots which are clearly visible in the 15 shot below.

    [​IMG]

    Trim pots

    [​IMG]

    The DSL20 gutshot photo Ampmadscientist posted earlier doesn't have these since it is self biasing.
     
    Last edited: Nov 8, 2018
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  16. stickyfinger

    stickyfinger Active Member

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    Hmm guess Marshall was wrong or the person spreading the news was misinformed.

    I initially figured the new 20 1 and 5 watts were based off of the 2012 RI 5/1 watt amps.

    I new Marshall wouldn't go Blackstar on us Lol!!

    Thanks for the clarity
     
  17. guitarman3001

    guitarman3001 Active Member

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    I wish they would have gone Blackstar on us..... I might not have had to return 4 of them before finally getting one that worked right!!! :sad:
     
  18. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    I was making the assumption that all the PI's were s/s because I've read it in the forum here, so, I just figured what was said about the 5 & 1 watters applied to the 20 as well...
     
  19. ibmorjamn

    ibmorjamn Well-Known Member

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    That is the way it should be !
     
  20. stickyfinger

    stickyfinger Active Member

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    Ive heard the 20 had a SS PI for months as well.


    I think I might get a 15h and mod the clean and od channels to clean red and OD green.

    My 40 is just to big and I hate combos. No tone suck no Reverb or a SS loop. How can I go wrong LOL
     

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