Modded JVM sound clips

Discussion in 'Marshall Amps' started by em07189, Apr 12, 2021.

  1. em07189

    em07189 Active Member

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    Ok, I recorded some sound clips of my moded JVM 410H,with my phone.

    Guitar PRS custom 24 stock pickups, marshall 4x12" vintage.

    Overdrive 1: green mode:

    https://drive.google.com/file/d/13a5vLJhw_t5heQeNf-3yFG8w6uEVAE-C/view?usp=sharing


    Overdrive 1_orange mode:

    https://drive.google.com/file/d/1LWIQYLEHr-bNoL1ZoZXiRCInN1DhNpfR/view?usp=sharing

    Theres is a lot of chuga chuga so that you can see the tigth and definiton the amp has now on the low strings


    The amp is near of what i want, almost perfect, but i still think that it misses something.

    What do you guys think of the mods i've done?
     
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  2. Sapient

    Sapient ā€€ Silver Supporting Member Platinum Supporting Member

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    Yes! Sounds great! You've gotten your money's worth, or time's worth anyway.

    OD green has an excellent roar and high-end TWAAAANNGG now ...like the tubes are on fire!

    :yesway:
     
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  3. em07189

    em07189 Active Member

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    Yes i also like to ear a crunchy high end, better than the compressed sound the amp had before the mod.
     
    Last edited: Apr 12, 2021
  4. Sapient

    Sapient ā€€ Silver Supporting Member Platinum Supporting Member

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    Yea, I had the JVM410H for some time. I personally could not stand it. One, because of something YOU fixed - that compressed and muffled sound, like you were listening to it through a cracked open bedroom door. Or, the typical towel over the speaker thing.

    You've made that sound so good now. Good job ...or choice to have it done!
     
  5. em07189

    em07189 Active Member

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    Thats the problem with all marshalls after the JCM 800, JTM45, SLP, 1987, all the models have to be modded to sound good. :)

    When i bought the JVM i liked the tone, not 100% satisfied with the amp, but with age my tone taste start to shift towards a less compressed sound.
     
  6. Sapient

    Sapient ā€€ Silver Supporting Member Platinum Supporting Member

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    Actually I should correct myself ...the only thing I didn't like about the amp was the sound. Everything else was fine. If you've got every channel fixed up then you're good to go.

    The 6100 was the last one I liked, myself. There are a lot of throwbacks now that go back to when they sounded best. So, in a sense the "newer" ones are sounding good too. If that makes sense.
     
  7. JCMDOUG

    JCMDOUG Well-Known Member Gold Supporting Member

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    Love the TWAAAANNGG and definition of all the notes is the cords.

    I would like to hear some runs up and down the neck with some bends and notes feeding back. yes its a list of stuff but I needed for a full evaluation. What I hear sounds great.

    The missing something thing (I have never found an amp that gets it all right for all the sounds I need to play)

    The power amp it can limit/effect sound (loose like a Vox or tight like a stock JVM) to find the missing thing you can loose good stuff along the way.

    what mods have you done so far like adding choke/neg-feedback remove C83 or plexi mod
     
  8. em07189

    em07189 Active Member

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    Hi! JCMDoug

    When i start to be unsastified with the stock tone from the JVM i started to check the mods from the JVM forum but still i was not happy with the results. i was also not happy from what i listen from guys that modded the amp, or amp moders.
    JVM its a amp with great features so it was a waste not to try to mod the amp before selling it.

    The mods i have done that are from the JVM forum:

    -Choke and filter caps mod
    -Anti-compression mod (inclusive put R71 to 100K)
    -plexy cap mod

    Mods to move the amp tone towards more jcm800 sound:
    R118 to 100K
    Remove R131

    I have changed C12 and C14 to 22nf, but i found that this mod is not so important for the tone, but can add more clarity to the overall result also.


    From the time i spent in trial and error i would like to the mods bellow to be called the "Rod mods" wich is my name if you guys dont mind :) :)

    Remove and Bypass R93 - less muffled sound, more gain, less darker sound, more dynamics.
    Put a resistor of 4,7 meg in C66 place - Wich lowers the signal entering in V6a in parallel with R117, makes the tone with more clarity, more tighter OD1, OD2 and crunch channel
    Put a 100k resistor in parallel with R128, lowers the gain, adds more clarity more definition, more tighter sound in the lower strings.
    Put a 330k resistor in R129, more definition, a little more mids. more clarity for the crunch channel also.
    I removed C44, but you cant put a little cap maybe 50pf. this gives less compression sound, more crunchy highs.
    You can leave the stock R94 , or increase to taste up to 330k or 390k to give more clarity to the tone.

    In the front panel pcb i also have changed C205 to 500pf.

    I lowered the negative feedback resistor to 56K, to have a more tigher responce and less highs.

    I still think that the amp misses some gain for the bassier side of the strings or the lower strings, maybe something like put a 2.2 nf in parallel with R203 from the front panel could improve the bass responce.
     

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