Do Marshalls Really Have a Midrange Hump?

Discussion in 'Marshall Amps' started by Seventh Son, Mar 26, 2020 at 9:11 PM.

  1. Seventh Son

    Seventh Son Well-Known Member

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    I always hear how British amps (i.e., Marshall) are voiced to have a prominent midrange or how Marshalls have "that midrange honk," whereas American amps are voiced with a mid-scoop, but if you look at the typical Marshall tone stack, it is pretty scooped on most common EQ settings (although not quite as scooped as a Fender). Why, then, do we refer to Marshalls as having a prominent midrange, when, in order to emphasize the midrange, you'd have to set the Bass-Middle-Treble to something extreme like 0-5-3?
     
    Last edited: Mar 26, 2020 at 9:51 PM
  2. Shane Stevenson

    Shane Stevenson Well-Known Member

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    Your gonna get some really technical but correct answers here...there are lots of brilliant minds who know the science behind it all.

    I’m gonna give my my simple minded and opinionated theory. With the Marshall amps I own, when you really crank them up and cook the tubes then the tone controls become less effective and the mid range comes alive. It’s really a wonderful thing! When my Marshalls are ran at clean, low volume then their much more scooped. So to me it just proves that real Marshall mid range magic happens when you turn them up.

    Add an attenuator and there isn’t a venue I can’t play! BTW, lots of Dr. Z amps are like this too.
     
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  3. Gene Ballzz

    Gene Ballzz Well-Known Member

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    That "0-5-3" ratio isn't really extreme at all. In fact it's fairly typical for many Marshall users to have a similar ratio, but often a bit more like 3-7-5. Of course at lot of this can depend on the cabinet used and what speakers are in it. For example, a 4x12 with greenbacks can have quite a bit of bottom end oomph, so the bass control needs to be left fairly low, but the same exact amp into an open back 1x12 combo might need the bass set fairly high! Go here and play with this:

    http://www.guitarscience.net/tsc/marshall.htm

    Once you get how interactive the controls are with each other, you'll see how those in the know can acheive either the dramatically "scooped" or "humped" mid sound and everything else in between. It might helpful to look at a schematic for the actual component values of the amp you're thinking of, as those values can dramatically affect the response of the tone stack.

    Have Fun,
    Gene
     
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  4. Gene Ballzz

    Gene Ballzz Well-Known Member

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    Oh,
    I see the differently labeled link in your first post showing that you have already played a bit!
    Just Sayin'
    Gene
     
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  5. South Park

    South Park Well-Known Member

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    The tone stack is a band pass filter . The the voicing is the tone caps in the preamp . Hope that helps
     
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  6. d95err

    d95err Member

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    You have to take the speaker into account. Guitar speakers actually have poor treble and bass response, effectively resulting in a big mid hump.

    Back in the day, guitar amps were going for a flat response (there was no real difference between guitar, microphone or accordion amps). My interpretation is that the classic tone stack was designed to compensate for this, by adding a mid dip. As the Marshall tone stack has less of a mid dip than the Fender, the end result is a mid emphasis.

    There are other tone shaping going on in the preamp too of course. A classic Fender "Blackface" has a pretty much flat frequency response, with exception of the tone stack. The Marshall "Plexi" bright channel is shaped to accentuate mid-treble frequencies.

    When you start to crank the amp up for distortion, you use the one stack to shape the signal before it hits the phase inverter and poweramp (where most of the distortion happens). You don't want a lot of bass, as this results in muddy distortion. Therefore, many players turn the bass control way down (I usually run Bass 0, Mid 10, Treble 10...). This further accentuates the mids and treble. The treble is then naturally attenuated by the speaker's limited frequency response.

    The speaker really is the key though. Play a Marshall fairly clean through a Fender-style speaker and it sounds pretty much like a Fender. Crank a Fender though a Greenback 4x12 and it sounds pretty much like a Marshall.
     
  7. headcrash

    headcrash Active Member

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    I think there are several things to take into account. First, many modern (higher gain) Marshalls do not differ so much from most of the other higher gain amps out there. I consider them however to be tweked with some kind of upper mid/treble emphasis. Many of the others are tamed there, which makes them sound good and pleasant for many occasions, but often the don't bite through a band situation or in a mix.
    Whether an amp is midrange heavy depends to a certain measure on the tone stack, but not exclusively. There's many places to sculpt the tone, especially in modern amps.

    The midrange scoop seen in the tone stack is inherent to all such tone stacks. Where that scoop sits and how "deep" it is, depends on the values of components. But as 7th son said, the scoop is not as deep as the fender scoop, and so we tend to say Marshalls are more midrange heavy.

    When speaking of Plexi-style non master volume amps: to my ears and feel they just sound right when cranked, with cranked mids and treble, and backed off bass. This sound maybe was the typical hard rock/heavy metal sound of the 70s and early 80s, and we were used to a midrangey guitar sound. Also bands sounded more midrangey, since sound systems weren't as good as today.
     
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  8. Seventh Son

    Seventh Son Well-Known Member

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    This is so true. My DSL15C is a completely different amp when it's cranked past 8. However, it also sounds a bit muffled on super high volumes. In order to get a true mid hump on lower volumes, it would be necessary to put bass, middle, and treble on 0. How crazy, right? I've found that for low volumes, putting bass and treble on 0, and mids to 10 actually sounds pretty good. On the TSC, those settings produce an even response.
     
    Last edited: Mar 27, 2020 at 5:26 PM
  9. South Park

    South Park Well-Known Member

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    Guitar pick ups and phone voice coils are heavy on the mids . So the tone caps roll off mid frequencies . The tone stack is a high low band pass filter . What all this does is to keep it all the frequencies leaner . This is just so cool
     
  10. ken361

    ken361 Well-Known Member

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    My 800 combo sounds best master maxed:)
     
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  11. Kinkless Tetrode

    Kinkless Tetrode Well-Known Member

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    On a technical level there is a resistor by passing the treble pot and acting as a shunt to the bass pot and the midrange pot (a fixed resistor in a black face or silver faced Fender). This resistor is called the slope resistor as it controls the eq slope of the tone stack.

    On a tweed amp this resistor was 56K. The JTM45 and the super bass also used 56K.

    The super lead plexi changed the slope resistor to 33k. This is also the value used in 2203/04s and DSL ect... This gives the upper mid emphasis we associate with lead Marshalls.

    Fender went the other way to 100k with black/silver faced and brown amps. Hiwatt used 100k too. A 56k slope resistor is common mod to Fenders to give them more of a tweed voice.

    The DSL classic channel clean has a fixed black faced Fender tone stack built in. It like the mids are permanently fixed on 4 with a black face tone stack. This built in tone stack is by passed when you push the button and change the classic channel to crunch.
     
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  12. Gene Ballzz

    Gene Ballzz Well-Known Member

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    That's some interesting stuff. I'm especially intrigued by the info concerning the DSL. The fixed Fender values makes sense when listening to the difference between the Classic and Ultra channels, as well as the difference between clean Green and red Crunch on that Classic channel of the 40 and 100 watt models. What about on the DSL 20 that only has one mode for each channel? I personally feel that on the DSLs in general, the Classic channel is where it really shines!

    Thanx 4 The Info,
    Gene
     
  13. Kinkless Tetrode

    Kinkless Tetrode Well-Known Member

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    I don't know about the DSL20, but the DSL15 only has the classic channel clean with the built in Fender tone stack. There are no knobs of course, its just fixed value resistors. On the DSLs with Classic channel crunch mode the Fender tone stack is by passed when your in crunch mode. In crunch mode you basically get a 2203 preamp signal path but with more gain.

    I studied a schematic of a Bogner Shiva awhile ago and he did a similar thing for its clean channel.
     
  14. Matthews Guitars

    Matthews Guitars Well-Known Member

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    EVERY guitar amp has a midrange hump to its EQ curve. If you were to play your guitar straight through your stereo or PA system, you wouldn't like it much. In order to have it starts sounding like a guitar you want to keep hearing, you'll add midrange and drop treble.
     

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