Marshall DSL 50/100 Clean/Crunch Footswitch - at last!

Discussion in 'The Workbench' started by een7gdr, Oct 20, 2009.

  1. een7gdr

    een7gdr Member

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    As some of you are aware, I have been working on a mod to allow the clean/crunch modes of Channel A on the DSL 50/100 amps to be footswitched like the main channels. Well, my final boards have just arrived - just as Im going on holiday (Bad timing!).

    You can see some pictures below of the prototypes to give you an idea of how it goes together. The most basic installation replaces the main switch with a number of relays. This still gives a front switch but can connect to the small Jack PCB that should be mounted at the rear of the amp (normally in place of the reverb jack) to allow a footswitch to be used. If you are prepared for the work, 3 wires from the PCB can connect to the main volume pot for that channel (requiring removal and re-insertion with 1 pin bent back) allowing the crunch volume to be dropped to match the clean channel using an on board potentiometer.

    Heres the pics of the prototypes, note the final versions have only 3 wires to connect for the volume adjustment and can be cut off if not required.

    [​IMG]

    [​IMG]

    The prototype has been in my amp now (a 1998 model) for a couple of months and Im actually using the crunch channel now it great!. Before i just used the clean channel and a TS-9 for a bit of crunch but theres loads more sounds available now. I currently have a prototype winging its way over to be tried in a newer amp (2006 i think).

    The install is completely reversable assuming you dont throw away the old switch/reverb jack!
     
  2. jcmjmp

    jcmjmp Well-Known Member

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    Excellent news! Finally, someone put the time in to do this.
     
  3. shawkey

    shawkey New Member

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    this is the best news i've hears all day! keep us posted een. btw enjoy your holiday
     
  4. 00jett

    00jett Member

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    hmmmm... Interesting
     
  5. Buggs.Crosby

    Buggs.Crosby New Member

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    I have been dying to find this mod as well as the same mod for the ultra channel
    when your back and these are ready shoot me a pm and consider one sold!
    Enjoy your holiday.....Wish i could take one
     
  6. javier pintos

    javier pintos Active Member

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    hey i`m interested to , got some sound clips?, what is your ball park price for this?
     
  7. Ken

    Ken Well-Known Member

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    Nice!!! Pity Marshall didn't work this out themselves....

    Ken
     
  8. thrawn86

    thrawn86 Well-Known Member

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    Would someone clarify what this does? I'm not familiar. :confused:
     
  9. Buggs.Crosby

    Buggs.Crosby New Member

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    It switches between the two modes on the classic gain channel
    with the added benefit of keeping the levels the same when switched
     
  10. Buggs.Crosby

    Buggs.Crosby New Member

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    If i did not phrase this correctly someone please correct me
     
  11. thrawn86

    thrawn86 Well-Known Member

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    No I think you did; I didn't understand at first.....this is to deal with the EQ differences on the two channels.
     
  12. jcmjmp

    jcmjmp Well-Known Member

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    No.

    This device allows you to:

    Use a footswitch to change from clean to crunch mode on the green channel. It also has an adjustment for making the volume levels the same between the clean and crunch with a single transistor.

    This basically turns the DSL into a 3 channel amp.
     
  13. thrawn86

    thrawn86 Well-Known Member

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    Seee? This is what stupidity gets me!! Thank you for the clarification. I didn't know about this at all. Very cool. :thumb:
     
  14. een7gdr

    een7gdr Member

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    Exactly thanks jcmjmp. Just found an internet cafe :)

    In principle this mode will also work if fitted to the lead1\2 switch position, however if you need both lead1\2 and clean\crunch youll need to mount 2 extra jacks on the rear, assuming one uses the reverb position the other can be mounted in some dead space between the main footswitch jack and the transformer, this would require a hole drilling and some bravery.

    The price excluding shipping for this mod will be £40 UK which due to our very poor exchange rate at the minute makes this about €44 or about $66. Shipping will be £2 for UK, £2.50 for Europe or £3 for the Americas. If youre interested then please PM me and we can sort out payment (through paypal if possible) once i get back. Due to the build time for these I cant do more than 5 per week.

    Ill let you know when i return.
     
  15. solarburnDSL50

    solarburnDSL50 Well-Known Member

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    Great work een. I will keep you and this in mind for later. I can't pay the bill yet but as soon as I get some free money I will PM you.

    Again, nice work!
     
  16. 00jett

    00jett Member

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    OK!!! now youu have me hooked. drilling some holes doesn't bother me at all. The only thing im wondering is if there is any way to mount the volume for the channels on the amp face plate, say in place of the reverb nobs or something (if its too hard dont worry about it)? I use the reverb in my rack unit which is why i wonder about this. oh man now im buzzing with ideas.
     
  17. MaidenStrat02

    MaidenStrat02 New Member

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    Alright boys and girls...what you've all been waiting for. Graham sent me a prototype to install and test. If you have experience working with amps and know how to discharge your filter caps you are good to go. It took around 4 hours for me. No point in getting alarmed, I'm very careful about things. The mod calls for you to remove the 2 PCB's so you can do the work. I spent a considerable amount of time drawing up wiring diagrams for all of the boards (4), switches, and trannys. This way I'll always have a reference to fall back on in the future. I decided to to do option #2. Everything went smoothly, one caution though. Be careful when you bend back tab 3 on the channel A volume pot. You must solder it on just right so you are able to install it back in place so that the legs fit back into the holes.
    Other than that it works BEAUTIFULLY!!!! :D:D:DNo noise and no latency between switching the 2 channels from what I could hear. I didn't get to really dive into real loud volumes, I was messing around at about 2 1/2.
    Anyway, you guys need to get this mod installed. Graham really knows his stuff and I swear by it. I also have his F\X Loop mod that removes all of the crosstalk in the loop. Here's some pics of my DSL50:

    The switch mod board:
    [​IMG]
    The reverb board:
    [​IMG]
     
  18. een7gdr

    een7gdr Member

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    Thanks MaidenStrat as all seems to be working then i can assume that the mod has been tested successfully on both 1998 and 2006 DSL models. I would presume that it is should be compatable with all models in between and more than likely the current range of amplifiers.

    As for using the front face knobs for the crunch volume, this can be done but you/I would have to find a new 1Mohm volume pot to fit into one of the reverb positions. Ther reverb pots are 20K on my amp and would load the pre-amp section too much. However, once a replacement is found it is almost as easy to perform the mod using the new controls as it is the standard option (as described by MaidenStrat). You may need to perform a small mod to link the output from the remaining reverb pot so that the one pot controls both channels but that should just be a case of one wire link.

    I have some orders already, and hope to ship the first lot by the 9th November. Again, please PM me if you are interested in the mod.
     
  19. een7gdr

    een7gdr Member

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    Finally back off holiday and got myself sorted out!

    The first batch of units should be posted on the 9th November. With regards to adding seperate volume controls for the crunch channel (and the lead 2 channel if you dont want any reverb!) I have sourced some identical 1M volume pots for this option. To add a single volume knob for the crunch channel you would have to remove the reverb B knob and pot (its a 20K i think) and mount the new pot in its place using only the mounting legs. The pot legs need to be bent back at 90degrees so that the wires to the footswitch mod can be soldered on to the top side of the PCB. The output of the reverb A pot will need to be linked to where the output of the B pot was connected so that the single knob controls both channels. Again, if these instructions are followed, there is no reason why this cannot be reversed 100% to return the amp to stock should you need to. Full instructions will be supplied with the kits once i get it all written up.

    I can add the spare volume pot if required to the kit for an additional £1.50Otherwise they are available from Marshall for a bit less but theres a £3.50 postage charge on their orders. Please let me know if you want these pots and i will amend the price accordingly.

    Thanks for the orders so far, Ill confirm to everyone individaully once they are dispatched.
     
  20. gag halfrunt

    gag halfrunt New Member

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    Wow, I've been looking for a mod like this for years! Excellent.

    Have you already sold out of your first run?
     

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