DSL100HR Amp Schem and Bias

Discussion in 'Marshall Amps' started by David Reid, Jan 17, 2021.

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  1. David Reid

    David Reid New Member

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    I got myself a new amp head and was wondering where to find the schematics and bias setting for the tubes in this head? Can anyone help me with this.
     
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  2. South Park

    South Park Well-Known Member

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    Is thar a problem with the amp . If it sounds good leave it as is
     
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  3. SkyMonkey

    SkyMonkey Well-Known Member

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    Hi @David Reid and welcome to the MF :welcome:

    Someone did post some DSL100HR schematics but the full set is still incomplete.
    They are dated 2015, so are most likely early drafts from before production started.
    The actual amps are likely to differ in some ways from these early drafts.
    https://www.marshallforum.com/threa...cs-are-finally-out-there.105345/#post-1779118

    There have been several bias threads for the DSL100HR.
    Here's one: https://www.marshallforum.com/threads/dsl100hr-external-bias-point-question.100955/
     
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  4. Max Gahne

    Max Gahne Active Member

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    I don't have a DSL100 but looking at the schematics I would be thoughtful about biasing it. It appears to change bias voltage to match the hi/lo power voltage using optocoupler LTV826. I would want to measure factory bias voltage and current in both hi and lo power modes and think about what they've done. Then make sure I kept both hi and low bias current in a safe range if I tinkered with it. It appears that when you bias it on hi power you're also changing the lo power bias and vice versa. It might be possible to get one or the other out of range. Or maybe not. The factory setting would be in range for both power modes. I agree with South Park, if it sounds good leave it alone.
     
    Last edited: Jan 17, 2021
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  5. David Reid

    David Reid New Member

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    Thank you very much!
     
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  6. Mitchell Pearrow

    Mitchell Pearrow Well-Known Member VIP Member

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    :welcome: To the forum
     
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