My JVM 410 sounds bad

Discussion in 'Marshall Amps' started by bobbyvasco, Oct 16, 2020.

  1. bobbyvasco

    bobbyvasco Active Member

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    It sounds just flat....there is no depth....so I dont know how to diagnoze it.....the sound is hard to explain, it sounds thin, not full
    so is the 1960 cab or marshall....i have it now for few years and the valves are still working
     
  2. scozz

    scozz Well-Known Member Gold Supporting Member

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    Sorry I can't help you, other than give you a bump,.....


    Give it some time, someone will respond. Would be better if you could give a few more details of what's going on with your amp.
     
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  3. pedecamp

    pedecamp Well-Known Member

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    Did it sound good in the past? Clean all the inputs, pots and tube sockets with Deoxit electronic cleaner. Check your bias and adjust if needed. If it still sounds flat get some new tubes and rebias. :yesway:
     
  4. avspecialist

    avspecialist Active Member

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    I have a 2007 JVM410H. For the most part the 410H wasn’t bad, especially after 3 or 4 very simple Casey Butt mods. I have a lot of amps and don’t play the JVM all the time. Earlier this year I went to use it and it sounded exactly like you described. So I did a preamp tube roll, no real change. I’ve had JJEL34’s in it for quite a few years, probably only 75 to 100 hours on them. So after swapping the preamp tubes and no real change, I decided to try different power tubes. I had a set of The Preferred Series EL34’s form The Tube Store. I installed them, I biased them based on 120 volt wall voltage at 81mv for 1 set and approximately 79/80 for the other set at 457 plate voltage. I also viewed the output sine wave on my scope. Knowing these voltages is very important to get the power section working properly. Unquestionably these new tubes really increased the bandwidth from bass to treble, but the amp is now very smooth, articulate and responsive, even better than before. After the tube install, I recently redid my 1960A cabinet with 4 Celestion Creamback 65’s. This amp is perfect now and I feel no additional need to mod or experiment with the amp any more. I just enjoy all the channels now. Please let me know if you have any other questions. Bob
     
  5. Jethro Rocker

    Jethro Rocker Well-Known Member

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    OP needs to post channel settings etc. Also, remember he is the one who had feedback issues using a 100 watt amp on full, yes, full in a flat. I take the current issues with the JVM with a very large block of salt.
     
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  6. wolfpack

    wolfpack Active Member

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    Change your power tubes
     
  7. Casey_Butt

    Casey_Butt Member

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    Amps are a weird thing. When I first got the 410H I wasn't impressed. Now I look back and conclude that I was simply retarded and I honestly can't see me ever wanting another amp as my #1.

    The room, the guitar, what you're used to etc, all make a huge difference. Change speakers, change strings, change your underwear, come back a week later and everything changes. I hear people saying the JVM is sh!t, the JVM is the greatest Marshall in history, etc, etc, and there's no logical accounting for it all.

    There are times when I thought the JVM sounded flat. I have amps that sound fuller and broader, but not by much. Sometimes it's a matter of choosing your battles - there are things that the JVM excels at and things where it might trail behind a bit.

    In full disclosure, I have modded the sh!t out of my JVM. Not really because I felt it needed it but, as an engineer and a retarded (as I said) perfectionist, I couldn't resist. Yet every time I play a bone stock JVM I'm still able to get kick-ass tones out of it. Sometimes it's a matter of letting it be what it is rather than trying to shoehorn it into being something else.

    With all that gibberish out of the way, if I had to guess, I'd bet most of your "depth" problems would be solved with the simple negative feedback mod. The JVM power amp is fairly restrained in its stock form (and that's deliberate so the power amp stays very controlled with high gain). If you can get someone to do the simple -ve feedback mod (or do it yourself if you're comfortable with it) it will wake the beast up entirely.

    I don't mean to put you on the spot avspecialist but do you remember exactly what the -ve feedback mod was? That was a long time ago. :)
     
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  8. EADGBE

    EADGBE Well-Known Member

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    It may be time for a tube change.
     
  9. bobbyvasco

    bobbyvasco Active Member

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    so it could ne also my 1960 cab? Maybe the speakers are bad?
     
  10. crossroadsnyc

    crossroadsnyc Senior Moderator Staff Member

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    Start simple, bro. I'm not a tech by any stretch of the imagination, but my first thought was that your tubes might be in need of some service (rebiased / swapped). Being that I'm not a tech, if I were you, I'd search out a local tech and have him/her give it a thorough checkup.
     
  11. bobbyvasco

    bobbyvasco Active Member

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    it sis weird, but sometimes it sounds very good, some times very flat...seems like longer time the amp is on it sounds worse and worse......
     
  12. crossroadsnyc

    crossroadsnyc Senior Moderator Staff Member

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    Are you doing anything different? New gear? Playing in a different room? Have you changed any component of your signal chain? Was your amp touched by an older man with long white hair?
     
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  13. royslead

    royslead Well-Known Member

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    Do you mean the guy in the white van?
     
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  14. crossroadsnyc

    crossroadsnyc Senior Moderator Staff Member

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  15. steveb63

    steveb63 Well-Known Member

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    My worthless two cents is "settings"

    Let us know settings and channel, imo sounds like ear fatigue.

    Of course, just my opinion, but it sure sounds like settings, usually a tube amp sounds better after it being fired up for a while, not worse as described.
     
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  16. JvZ

    JvZ Member

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    Did you fix it .?
    How was bias set .?

    i’ve seen JVM’s with very poor bias settings, including my own 210 which was set extremely cold.

    Took them up to 37, which is 74 per side.
    25/470 x .7= 37.23 (x2= 74,46)

    I run JJ EL34’s (standard)
    Rest is stock.

    I am thinking about putting a ECC823 in V6, to make gain somewhat less hyper on OD orange/red.
     
  17. Georgiatec

    Georgiatec Well-Known Member VIP Member

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    Looking for something I don't remember what.
    I came to the same conclusion. I messed around with my 410H for 3 months. Wasted many band practices trying to find useable tones. Just sounded flat, almost processed. Footswitch got on my wick. High gain tones always seemed to be accompanied by squealing feedback. All the other band members agreed....not a patch on either of my Vintage Moderns.
     
  18. IOSEPHVS

    IOSEPHVS Well-Known Member

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    I love the Tube Store. I buy all my valves there.
     
  19. proxy

    proxy Well-Known Member

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    Well... I had both a regular and Satiriani model....No tubes will fix it of whatever you do to it....I suggest you to sell it and something much better...like Vintage modern if you on the budget as you can get them these days pretty cheap....And I am sure you have a few pedals sitting around and you'll be fine...Whats not to like?
    Good luck bro and keep rocking......
     
  20. ampeq

    ampeq Well-Known Member

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    Same here, I had 2 and they both were flat sounding. You can roll tubes and mod the hell out of it all you want, it’s still a JVM.
     
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