Jump! Jump! Jumper! Correct way and show your SLP

Discussion in 'Marshall Amps' started by suresh, Apr 16, 2021.

  1. suresh

    suresh New Member

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    Hey Everyone,

    I have an Sv20C since a week and Love this thing. Best amp I have owned.

    I am a little confused about the Jumper option. I see lot of the Jumpers connected from channel 1 low sensitivity to channel 2 high and guitar plugged into the low sensitivity channel 2, but i also see a lot of them connected from Channel 2 low sensitivity to channel 1 high and guitar into channel 1 low sensitivity.

    do they even tonally matter? if yes then how? I am a noob to 4 input amps so pardon my ignorance.

    cheers
     
  2. 99_Revolutions

    99_Revolutions Active Member

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    With my plexi clone, I run top left input alone 99% of the time. If I do jump, I just add the cable to bottom left and top right inputs. All I hear it do is cut some treble(due to the normal channel not having the bright cap in the circuit and being blended with the treble channel). I recommend just experimenting with the amp and find what jumping/input works for you!
     
  3. Chris-in-LA

    Chris-in-LA Well-Known Member

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    I’ve never seen anyone plug into a 4-holer in either of those ways. Not that any way is wrong, I’ve just never seen that.
     
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  4. johan.b

    johan.b Well-Known Member

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    For the channel jumped from, it makes no difference.
    For the channel Jumped to, it does.

    The way the jacks are connected, on the channel jumped from, there will be 68k resistor from Jack to input, then another 68k to the output.
    So 136k series resistance from gitarr to jumped output. Plugging into input on "jumped to" channel, there will be significant attenuation plugging into the low and much less so, plugging into high(due to that series resistance).
    The series resistance total created through jumping, at this point, will affect the highest highs (well, above what my old ears detect and any popular guitar speaker can recreate, but still) so most sense is to jump from bright channel (either input) to normal channel high, where loss of highs can be compensated by just adjusting the bright channel...
    J
     
    Last edited: Apr 16, 2021
  5. junk notes

    junk notes Well-Known Member

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    • Jump option 1, Y-cable channels 1 & 2 high.
    • Jump option 2, Y-cable ch. 1 high, out ch.1 low to pedal/effect in, pedal out to ch.2 high.
     
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  6. crossroadsnyc

    crossroadsnyc Senior Moderator Staff Member

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    Agreed.

    The way I do it, and I believe is probably typical for most people, is to plug your guitar into the high sensitivity of channel 1, and then use a patch cable to jump from the low sensitivity of channel 1 into the high sensitivity of channel 2.
     
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  7. suresh

    suresh New Member

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    thanks guys,

    I'll try the jump from low 1 to high 2 with guitar on high1
     
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  8. Matthews Guitars

    Matthews Guitars Well-Known Member

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    I always do it this way:

    Guitar into high 1.
    Jumper from high 2 to low 1.

    I use Volume 2 to warm up the bass a little bit. It's always set lower than Volume 1.
     
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  9. Chrome

    Chrome Firebird Freak Gold Supporting Member

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    on the NMV amps (as in my 76 JMP) it matters, it allows you to drive both channels to tailor tone more to your liking. I don't know much about the SV20C but appears to be a NMV as well, so yes, it allows you to add more depth to your tone. you will want to jump bottom channel 1 into top channel 2.
     
    Last edited: Apr 16, 2021
  10. FutureProf88

    FutureProf88 Well-Known Member

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    Just play around with it. IME the effect is really subtle.
     
  11. neikeel

    neikeel Well-Known Member

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    But surely:


    I don’t jump.
    Top left for me if the amp can’t give what I want like that it is unlikely to be staying.
     
  12. Gene Ballzz

    Gene Ballzz Well-Known Member

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    Most folks plug unto the high input of the channel they want to be most dominant (High Treble or Normal) and dial in the other channel to either brighten or darken the overall tone. Here's a very good description of what all the different combinations do, including impedance values. It's referencing a Fender, 5E3 Tweed Deluxe 4-hole but they and the 4-hole Marshalls are wired identically to the grids of V1A & V1B. It's actually a quite complicated, yet brilliantly conceived input circuit! There really is a lot more going on there than most realize!

    https://robrobinette.com/How_Fender_Input_Jacks_Work.htm

    Obviously the similarities between the amps kinda stop there, although the interaction of the two jumped channels still can exhibit a slightly out of phase sounding character that most folks either love or hate!

    Just Sharon,
    Gene
     
    Last edited: Apr 16, 2021
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  13. wolfpack

    wolfpack Active Member

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    ABY pedal
     
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  14. suresh

    suresh New Member

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    Nah
     
  15. marshallmellowed

    marshallmellowed Well-Known Member

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    I used to jumper in the conventional manner, Treble lower input to Normal upper input. I've since stopped using a jumper, and have been using a "Y" cable for several years now, guitar into "Y" cable, then into Treble upper input and Normal lower input. Using this method, the lows of the Normal input retain more clarity (IMO). I do this with all my non-master amps.
     
    Last edited: Apr 19, 2021
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  16. JamminJeff

    JamminJeff Well-Known Member

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    My avatar to the left shows my current jumper configuration on the SV20H. I did test the amp before jumping, but it's been in this config ever since I finalized the set it up. It sounded so good this way, I forgot to try it a different way. I'm a set and forget type. That said, it's probably worth testing some other options now that I've had it awhile, etc.
     
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  17. Gene Ballzz

    Gene Ballzz Well-Known Member

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    Yes indeed, as mentioned in Rob Robinette's treatise, a "Y" cable will definitely provide different results than a simple jumper, especially the way you use it! A "Y" into both "Hi" inputs would be closest to the guitar into Normal Hi and a jumper from Normal Lo to Treble Hi. It would be interesting to read Robs take on grid stop and grid leak values with a "Y" cable? I'm guessing the "Y" into both Hi inputs gives about 500kΩ input resistance/grid leak and about 34kΩ grid stop for each channel.
    Just Wonderin'
    Gene
     
    Last edited: Apr 20, 2021
  18. suresh

    suresh New Member

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    humm have to try it, will try to get a Y cable.. any suggestions on a good cable?

    On another note.. can i daisy chain this one to a one input Bassbreaker 15, any one tried this, with any amp?
     
  19. Trelwheen

    Trelwheen Certified B.S. Launcher Double Platinum Supporting Member

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    It's just a jump to the left
    And then a step to the right
    With your hands on your hips
    You bring your knees in tight
    But it's the pelvic thrust
    That really drives you insane
     
  20. wolfpack

    wolfpack Active Member

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    Actually Yeah
    It works better than a Y cable imo
    Providing 3 options
     
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