A good mod for the class 5

Discussion in 'The Workbench' started by Crunchifyable, Apr 15, 2015.

  1. Crunchifyable

    Crunchifyable Well-Known Member

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    I was staring at the schematic contemplating Lyle's mods...when I realized there's something else to fix. I used to wonder why the Class 5 sounded darker when using the headphone output (headphone trick or low power switch).

    [​IMG]


    Turns out Marshall put a cap to ground (C50) on the attenuator circuit to make the output less shrill on headphones. If you remove C50 or R51 (R51 is easier to remove), the attenuated output now sounds more like the base tone of the amp. Easier to just remove R51.

    Everyone who uses the "headphone trick" should do this imo.
     
  2. iron broadsword

    iron broadsword Well-Known Member

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    Just discovered this. Thank you! I use orpheus' pot to control the attenuation, and always wished I knew why the headphone circuit destroyed the tone a little.
     
  3. DirtySteve

    DirtySteve Well-Known Member VIP Member

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    A person may not want to do this if they do use headphones because when I tried headphones with mine it nearly took my head off it was so "shrill" and would be even worse without the cap.
     
  4. pedecamp

    pedecamp Well-Known Member

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    I've probably asked this already at some point but is there a master volume mod for the Class 5? Are there any downfalls to adding this mod?
     
  5. DirtySteve

    DirtySteve Well-Known Member VIP Member

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    See Iron broadsword's post. The orpheus mod works great and works like a Master volume even though it really isn't. It's been so long since I had mine I forget the specifics, but I had the mod on mine (in fact I may have been the first) and it was awesome.
     
  6. iron broadsword

    iron broadsword Well-Known Member

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    Orpheus777's mod is just a pot that lets you control the headphone circuit, making it into an attenuator you can use from full volume down to zero, which IMHO is better than a master volume for this kind of amp because you'll still get the power tube saturation.


    I just did this on mine and it sounds right now in conjunction with the orpheus pot. I always found it lost some guts when using his pot. Not enough to really put my finger on, but enough to miss it when its gone. I'll need to do more testing, but right off it sounded better. I don't ever use headphones so i don't care at all what it sounds like with them..
     
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  7. iron broadsword

    iron broadsword Well-Known Member

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    Just revisiting this to confirm that after many hours of play testing afterwards, the amp does definitely sound the same as in full power mode now. Thanks again, crunchy.
     
  8. Alabama Thunderpussy

    Alabama Thunderpussy Well-Known Member

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    I do a master volume mod in addition to other things.
    http://marshallforum.com/showthread.php?t=80456

    I have some much better recorded video, but getting the guy who recorded it for me to edit it down and send me the results has been like pulling teeth with a pair of tweezers. I'll stick that up as soon as I get it.
     
  9. Don

    Don New Member

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    This is an awesome mod! I'm on my second Class 5 (I sold the first one 5 years ago and bought a C5-01 last November). This mod was exactly what I wanted from the amp!
     

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