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very loud Marshall head

Discussion in 'Recording' started by crazy_guitar, Jan 8, 2002.

  1. crazy_guitar

    crazy_guitar Guest

    Hi, I have a Marshall JCM800 100w!! and I love the cranked up sound, but its just TOO LOUD!!! I heard from a guy that you can take 2 out of the 4 power tubes out, (you can only take out the ones on the sides, or the 2 in the middle). And he says it works, but Im wondering if taking 2 power tubes out will ruin my amazing marshall sound that I get now, or will it just make it different wattage?? I dont wanna buy a power attenuator, if taking 2 tubes out works. (I know big part of a cranked up sound comes from the speakers distorting, but I dont care about that).
    so will this work?? I need help
  2. Bear's Gone Fission

    Bear's Gone Fission Active Member

    Jan 4, 2001
    It'll work, it won't hurt the amp, but it might not sound quite the same. One thing it does is change the load the input on your output transformer sees, which can alter the sound. Some folks say you always have to adjust the impedence selector to half the actual speaker load to protect the transformer (e.g.- set to 4 ohm for an 8 ohm cab). This is hogwash from the transformer safety view, as it's doing half the work it's able to, so the only consideration is that the impedence may effect the bandwidth, or may not. (Having a lower impedence load connected to a higher impedence tap tends to reduce bandwidth, and vice versa.)

    Now here's the real problem with pulling tubes: it still doesn't make a loud Marshall polite enough for most non-gig use, unless you think jachammers are polite. If your speakers can handle the power, maybe rig it so only 2 of four speakers are hooked up in the cab (I'm assuming 4-12"), which will also help tame some volume. If that isn't good enough, it's back to isolation booths or isolation speaker cabinets, power attenuators, or getting a smaller, studio friendly amp.

  3. mikemoritz

    mikemoritz Guest

    Was going to mention the powerbrake, but I always reply too soon.....sorry.

  4. crazy_guitar

    crazy_guitar Guest

    I just noticed that 50w marshall heads have only 2 power tubes. Is there a big difference beetwen pulling tubes out, and a made for 50w 2 power tubes amp?? maybe the impendance, cause you can use a 8 ohm cab with a 8 ohm output in your marshall.
    also..what will be the wattage if I pull the tubes out? 50w?
  5. Me, I got a li'l Gibson Goldtone, switchable between 6 and 15 watts. I'm a big believer in power amp and Celestion distortion. And of course most of the tone is in the hands of the player...
    I turn this li'l lovely up to ten, and damn it sounds nice. I've made recordings with it that sound extremely reminiscent of Jimi's several suped-up vintage Marshalls. This done with a Les Paul Custom ca. 1980.
    Worth a try! And you can always use your full-on Marshall with all tubes intact for those occasions where mind-numbing loudness in addition to killer fat tone is called for...
  6. Bear's Gone Fission

    Bear's Gone Fission Active Member

    Jan 4, 2001

    Some guys prefer the 100 watters for what they say are issues of tone seperate from volume (bear in mind the Fletcher-Munson effect, where louder things tend to sound fuller). The claim is generally that the headroom and breakup characteristics of the 100 watt output transformer is preferable, and some will go so far as to put 100 watt iron in a 50 watt amp.

    I don't want to commit to what wattage pulling tubes will get you, since I'm sure to be wrong. The 100 watt or 50 watt measures are generally inaccurate, or allowing as much as 10% or more THD. I've heard one figure that a nominally 50 watt Marshall (I forget which model) gave 38 real watts, where a Fender Super gave 45 or so, though the Marshall will certainly sound louder. I've heard of some 100 watt metal panel Super Leads putting out 150 watts (don't know at what THD spec). It's all pretty vague, so I don't bother much. And with possible impedence issues mentioned before, while you should get about half the wattage, it could be more or less. In other words, it'll still be enough to make eardrums bleed if pushed.

  7. MartinTurner

    MartinTurner Guest

    With a JCM 800 you can select the impedance of the output transformer using that pre-historic looking selector on the back.

    One of the first ports of call would be to check out a cab with higher impedance if you're not already at the max.

    You can also use less efficient speakers -- those classic Marshall 4x12 cabs were very, very efficient compared to a lot of modern designs.

    For an alternative approach, I had the shop put in an effects loop into my 1977 JCM 800 head. The not particularly unexpected side effect was that I could take a line off the pre-amp. This definitely doesn't give the same sound as cranking up the volume, but it may well give the sound you're looking for.

    Like the previous poster, I eventually chickened out and bought something smaller - a Mesa/Boogie combo. Sounds delicious. My JCM800 is still upstairs in the attic, rarely used... sniff.
  8. spp

    spp Guest

    Originally posted by Martin Turner:
    [QB I eventually chickened out and bought something smaller - a Mesa/Boogie combo. Sounds delicious. [/QB]

    Which one?
  9. MartinTurner

    MartinTurner Guest

    I went for the smallest one I could, as years of humping a Marshall stack around persuaded me to leave behind the kilos.

    I went for the Subway Rocket (non-reverb version).

    For a Boogie it's quite cheap. As a recording amp the non-reverb version is better, because it has presence which influences the other three tone controls instead of a spring reverb.

    One nice feature is being able to switch off the speaker and record direct from the balanced recording out (which also doubles cunningly as a stereo headphone out). Very good for later night stuff at home.

    The nominal power out is 15 watt RMS, but, seriously, its still way too loud to crank up anywhere outside of a gig environment.

    It isn't 'portable' in the way of the Marshall valve-state combos, but I think its total weight including the Black Shadow speaker is less than my JCM 800 head.
  10. Hack

    Hack Active Member

    Mar 20, 2001
    Little Rock, AR
    Its hard to beat a marshall stack for almost all rock guitars, for me. I do also have a Mesa Mark 4. The is a very good sounding 1X12 combo but, It weighs about 500 pounds, and there about 1000 knobs and switches, not your everyday knobs and switches either, we're talking 3 ways and push pull $*^t.
    Triode and pentode options, even the on off switch is 3way(Full power, and tweed power).

    All that said, this amp takes discriptions like "crunch" and "in your face" to levels marshall will never know. But its still not what we have been hearing for the last 20+ years.
  11. kylethompson

    kylethompson Guest

    Why would you not want to try a power attenuator? I use one with my 72 Traynor (similar to Plexi) and it sounds great, much better than a master volume (especially the phase cancel type) Try Power Soak. It's much cheaper than the Marshall one.
  12. Bear's Gone Fission

    Bear's Gone Fission Active Member

    Jan 4, 2001
    Better yet, avoid the Scholz Power Soak like the plague. It's a known serial killer of output transformers, the most expensive part of most amps. Use a good reactive load device instead, which will not only be safer, but will tend to create a more natural sound as well.


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