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Two Bad Dsl20 Heads???

Discussion in 'Marshall Amps' started by ALLsteven, Jun 6, 2018.

  1. ITburst

    ITburst Active Member

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    Is it by any chance the same sound as in the videos I posted above?
     
  2. JeffMcLeod

    JeffMcLeod Well-Known Member Gold Supporting Member

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    I've found that the reverb works surprisingly well, but only at a louder volume. At lower volumes, you can hardly even tell it's there, if at all. But up loud, it's quite competent, especially considering Marshall's historically weak reverbs.
     
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  3. ITburst

    ITburst Active Member

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    So, head number two.
    I type this with a degree of fear in my heart but so far this amp is perfect. I played it for about 45 minutes and now it’s just sitting here on while I watch a bit of tv. The first amp was acting up straight away so for this one to go this far is somewhat of a good omen. I’ve tried both channels, FX loop, foot switch, etc.
    I’ve got the reverb full as before, gain at half way, and some volume cranked on. All I hear it the normal hum of a tube amp. I hope this is the one!
     
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  4. PelliX

    PelliX Well-Known Member

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    No, the hiss could be the same, I'd say it seems less (but the video is obviously a bit hard to judge), but not the pronounced crackle that you had. It really sounds like a digital circuit with dirty power and/or interference. Take your run of the mill PC soundcard and turn it up beyond reasonable expectation - same thing, most of the time. I might be able to improve it a little which I'll see about when I replace the pots, but it's not at a level that I find problematic. It's more pronounced when I run the amp in high power mode, which sort of dovetails with my notion of it being power related. The e-out has the same noise floor, maybe even a little worse, but I wrote that off shortly after testing it when I bought the amp. :)
     
  5. gregr

    gregr Well-Known Member

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    I just repaired a blown effects buffer. It uses the same transistor that’s used in the gyrator circuit. Fun stuff.
     
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  6. IronVic

    IronVic New Member

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    I bought a DSL20Head (new) about 3 months ago.
    Yesterday, the guitar input and all the front knobs stopped working, however if I plug the guitar to the return in the FX Loop I get a nice clean sound. I am unable to change from classic gain to ultra gain or make it louder or less loud.
    All tubes light up and when I tap them lightly with a chopstick they all sound normal.


    I will return it as it is under warranty, but do you guys have any idea what could have caused it?
    Pedals running through the FX loop? TS, Rat, NS2, Wah.
    Thunderstorm (even though I unplugged the cable)?
    Powering on while unplugged from electricity?
    New guitar with active pickups that I bought yesterday and wanted to try out?
     
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  7. fitz288

    fitz288 Well-Known Yinzer Silver Supporting Member

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    If you are getting signal through the loop return, I'd suspect a preamp tube.
    They can still light up and not function correctly.
    Do you have a spare 12AX7 to rotate through V1, V2 & V3?
     
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  8. IronVic

    IronVic New Member

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    Thank you for the reply!
    Unfortunately no. It's my first tube amp and i thought tubes would last a while longer :)
    I can go tomorrow to the music shop to check if they have it over there. I'd rather pay 40 rather then stay with no amp for a couple of days or weeks.

    Should I get 1 or 3 tubes?
    Will different tubes change tone on the amp? if so any recommended brand to keep it's tone
    I noticed one of the tubes, the one on the left as you see it from the back, as an o-ring around (or something similar) it. Is it normal?
    Any of those things on my first post could cause the tube to go bananas?
     
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  9. gregr

    gregr Well-Known Member

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    You only need one extra tube to troubleshoot. Use it to change out the first one that is farthest away from the power tubes. If that doesn’t work then use the extra tube to swap out the one next to it. If that doesn’t work then something else is the problem.
     
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  10. fitz288

    fitz288 Well-Known Yinzer Silver Supporting Member

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    Tubes can go bad in a matter of seconds for no reason at all, or last for decades of abuse, always a good idea to have a spare, or 2, or 3.
    If you can't find local, I get them from Antique Electronic Supply (tubesandmore.com) or Amazon shipped in a few days.
    The O-ring is a vibration dampener on V1 - It's normal.
    The stock tubes say Marshall, but they are a combination of actual brands.
    As to what brand sounds better? - Everyone has a different opinion.
    Get what's available for now.
     
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  11. fitz288

    fitz288 Well-Known Yinzer Silver Supporting Member

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    Here's a link to the tube decoder thread.
    Stock Marshall Tube Codes | MarshallForum.com
    I just use JJ because they cost less.
    Tubes can affect the amp tone, but they are just one variable out of many between your guitar strings and the speakers.
     
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  12. Mitchell Pearrow

    Mitchell Pearrow Well-Known Member VIP Member

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    WELCOME TO THE FORUM
    As others before me have said, pick up spares to have on hand (tubes)
    and try the one at a time method, I don’t think anything you did was the culprit of the problem.
    I do hope that the preamp tubes are your only problem.
    Cheers to getting your amp back to normal.
    Mitch
     
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  13. IronVic

    IronVic New Member

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    Thank you Mitch for the welcoming!

    So I went just now to the shop and got myself 3 12AX7 JJ Valves. Cost me 10€ each.
    Replaced one by one and found the culprit. Valve #2 (middle one) went bananas.
    Thank you guys for the assistance I was already in panic mode that I would have to go back to a Solid State amp like my old (but new) Katana.

    I've been playing with an attenuator with the amp cranked to the max, so that may have also been a cause.

    BTW: These valves are a bitch to replace.
     
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  14. 6stringz

    6stringz Active Member

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  15. 6stringz

    6stringz Active Member

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    My friend had a old tube tester. Bought it for 4 dollars. His father used to work on old televisions. Best investment I made. Ax7 10000 hours, or can be a bad tube rite from the store.
     
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  16. Mitchell Pearrow

    Mitchell Pearrow Well-Known Member VIP Member

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    That’s great bro your amp is up and healthy again..
    Cheers
    Mitch
     
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