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Thread: Bassman 57 LTD sounding thin, fizzy is this normal?

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    Bassman 57 LTD sounding thin, fizzy is this normal?

    hey guys, picked up a Bassman 57 LTD and i find no matter what i do settings wise it just sounds either boxy or very thin! I've tried a few pedals in front it and when you drive with amp with fuzz or tube screamer or any distortion really it sounds thin, very fizzy and useable.

    from what i read this amp made for a perfect pedal platform. unfortunately i could try it when i went to pick it up with a pedal but so far my experience is yes the clean sound is ok but everything else is disappointing. the amp hasnt had much use i think 20 hours all up so maybe the speakers arent broken in or something? could it be that theres an issue with the tubes? cause if i push volume past 4 it starts to break up. or is it maybe i just prefer marshall more haha

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    Forum Member phantomman's Avatar
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    Re: Bassman 57 LTD sounding thin, fizzy is this normal?

    A couple of issues come to mind. First, as you mentioned, the speakers may have had insufficient break-in time. Imported Jensens usually require about 50 to 60 hours before their tone "ripens".

    Secondly, and what I suspect may be the fundamental problem, the power tubes are either tired OR they're incorrectly biased. Either scenario will produce the audible effects you're hearing.
    "When injustice becomes law then rebellion becomes duty."

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    Forum Member DanTheBluesMan's Avatar
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    Re: Bassman 57 LTD sounding thin, fizzy is this normal?

    is the amp new or used? 20 hours isn't very long. I put a brand new Weber into my old Princeton Reverb years ago. Thought something was wrong with the speaker so I called Teb Weber himself. He said the speaker needs time to break in. Not saying I didn't believe him but I was dubious. I tried it anyway and after about 3-6 weeks (memory's fuzzy) suddenly one day, it just sounded right. Man, I miss that amp.
    "Live and learn and flip the burns"

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    Forum Member Offshore Angler's Avatar
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    Re: Bassman 57 LTD sounding thin, fizzy is this normal?

    Mwh. A new Bassman should sound good right out of the box and then only get better with use. What volume setting are you using?

    Chuck
    "No harmonic knowledge, no sense of time, a ghastly tone, unskilled vibrato, and so on. Chuck is one of the worst guitar players I know" -Gravity Jim

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    Re: Bassman 57 LTD sounding thin, fizzy is this normal?

    i bought it used and the fella said it only had around 20 hours of use on it, the amp is in really good condition no marks or anything but it just sounds so thin! and the minute you drive it with pedals you get this god awful razor distortion, reminds me of the crappy cheap amps i had as a kid.

    ive tried numerous settings from youtube some gilmour settings


    greg koch settings

    presence at 7 mids all the way up bass and treble 0 on the bright channel and normal channel

    maybe the tubes or something are no good or what is re-biasing?

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    Forum Member Michael Smith's Avatar
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    Re: Bassman 57 LTD sounding thin, fizzy is this normal?

    Quote Originally Posted by kk101 View Post
    i bought it used and the fella said it only had around 20 hours of use on it, the amp is in really good condition no marks or anything but it just sounds so thin! and the minute you drive it with pedals you get this god awful razor distortion, reminds me of the crappy cheap amps i had as a kid.

    ive tried numerous settings from youtube some gilmour settings


    greg koch settings

    presence at 7 mids all the way up bass and treble 0 on the bright channel and normal channel

    maybe the tubes or something are no good or what is re-biasing?
    Biasing is setting the amount of current applied to the control grid of the tube to regulate the output (wattage) of the power tube. If the bias is set too "hot" the tubes will operate near or above their designed rating, and they will not last as long. You may have heard the term "red plating", which is what it sounds like, the internal metal parts of the tube glowing red hot. If the bias is set too "cold", the amp may sound anemic. Adjusting the bias is generally not something an inexperienced person should attempt, as the voltages you are measuring may be 400 volts or higher and could be quite dangerous.

    Another possibility is mismatched power tubes, where one is a lot stronger than the other. In a push-pull circuit like the Bassman, mismatched tubes would result in poor performance of the amp. But to determine whether the power tubes are reasonably matched also requires you to measure voltages and calculate plate current and plate dissipation. You should probably take the amp to a qualified amp tech to check the bias and power tubes plate dissipation. Ask them beforehand what is their standard bench fee for such service, it should be reasonable.
    "When You're Riding Down the Highway at Night, And You're Feeling that Wild Turkey's Bite" ZZ Top

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    Forum Member DanTheBluesMan's Avatar
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    Re: Bassman 57 LTD sounding thin, fizzy is this normal?

    there are many things that can cause amps to not sound right, but I've rarely found tubes to be the cause. yet everybody and their brother are always jumping at the gun to pull them first thing. If you have more than one amp and/or have spare tubes hanging around, you can take known good ones and try substituting. The danger with this method is that something could be very out of spec in the circuit and kill your known good tube. Tube amps should not be worked on by people who don't know what they are doing. It is fine to learn the ins and outs, preferably with an experienced person guiding you. Youtube videos, eh, not so much. Lot of misinformation out there. If it's your one and only amp, take it to a tech and yes, ask their bench fee. Know that you're probably going to spend 2 hundred and up, not counting parts. Newer amps with wave soldered circuit boards are nearly impossible to work on, it is often less expensive to replace the circuit boards. If the boards are unavailable, you're out of luck.
    "Live and learn and flip the burns"

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    Forum Member Offshore Angler's Avatar
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    Re: Bassman 57 LTD sounding thin, fizzy is this normal?

    Turn the amp off, make sure all the tubes are properly seated.

    Turn it on and observe the tubes to make sure they look like they're functioning properly. "Fizzy" isn't a normal sound for a Bassman. It may need to go in for a checkup.
    "No harmonic knowledge, no sense of time, a ghastly tone, unskilled vibrato, and so on. Chuck is one of the worst guitar players I know" -Gravity Jim

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    Re: Bassman 57 LTD sounding thin, fizzy is this normal?

    i'll post up a video on youtube maybe it will explain better

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