Marshall mid frequency?

[LP Freak]

Can someone tell me what frequency the mids are voiced at on a JMP? How about the highs?

 

[Kelly]

Found this on the google machine, cant confirm (the treble seems high)

Bass.... approx 100Hz
Mid.... approx 800Hz
Treble...approx 9-10Khz

 

[mmolteratx]

It depends entirely on where the knobs are set. There's no center frequency around which the tone controls boost/cut.

 

[Bloodrock]

It depends entirely on where the knobs are set. There's no center frequency around which the tone controls boost/cut.

I'm pretty sure they're all set to a specific range or else the EQ section would be parametric with a freq control like amps that have a "sweep" or "contour" control.

 

[LP Freak]

That's what I was thinking.^^

 

[V2a]

First off, there is no active boosting. The TMB controls are passive and only cut the signal in particular frequency ranges. So, turning the mid pot clockwise means that you are cutting less mids.

Second, the conventional TMB tone stack used by Fender and Marshall (and many other amps) are highly interactive. Setting your mid pot will affect your treble too. More on that below.

Third, the rest of the preamp (and power amp and power supply) plays a big roll in setting the voice of the amp. The very low frequencies are filtered out, which is why a JMP sounds glassier and has less bass than a Fender. Amps will add higher-frequency harmonics, but you won’t hear 9kHz due to the guitar speaker.

So in considering this question, you can think of it in two ways:
1. how is the preamp filtering the signal at different stages? does the overall design give you lots of bass? Mids? Treble?
2. how is the tone stack designed? Separate follow-up questions would include: What frequencies are affected by the Bass control? The Mid control? The Treble control?
The tone stack on a JMP will give you a mid dip at about 800 Hz. So with treble and bass up and the mid set at zero, there will be a reduction of the signal centered at around 800 Hz. And when you rotate the mid pot clockwise, you add back frequencies in that 'range'. However, the TMB controls are highly interactive, so if you keep rotating the mid pot clockwise, you will start to boost the treble frequencies too. Also the centre frequency of the mid dip will depend on where your Treble control is set. If it is dimed, the mid dip will be centred at ~600 Hz. If it is at noon, the dip will be centred at ~800 Hz.

 

[LP Freak]

Nice post thanks.

 

[moronmountain]

First off, there is no active boosting. The TMB controls are passive and only cut the signal in particular frequency ranges. So, turning the mid pot clockwise means that you are cutting less mids.

This is one of the reasons I would almost always dime the tone knobs on Marshalls when I played them. For me, it was the only way to get everything possible out of the amp. I always felt I was kind of "choking" some of the drive out of the amp when I would roll the knobs off a bit. I would basically just use the presence as a tone knob, and leave everything else sans the master volume dimed.

 

[V2a]

First off, there is no active boosting. The TMB controls are passive and only cut the signal in particular frequency ranges. So, turning the mid pot clockwise means that you are cutting less mids.

This is one of the reasons I would almost always dime the tone knobs on Marshalls when I played them. For me, it was the only way to get everything possible out of the amp. I always felt I was kind of "choking" some of the drive out of the amp when I would roll the knobs off a bit. I would basically just use the presence as a tone knob, and leave everything else sans the master volume dimed.

There's really only one rule for the TMB: set them where you think your amp sounds good. Having said that, keep in mind that higher gain amps with more than two preamp stages will throw away some of the signal between stages. Even when there is a volume pot that allows the user to crank the gain (allow as much signal through to the next stage), there are often series resistors that limit this effect. You do end up loosing drive, but that's not necessarily a bad thing (and for high-gain amps, it is essential).

 

[moltenmetalburn]

First off, there is no active boosting. The TMB controls are passive and only cut the signal in particular frequency ranges. So, turning the mid pot clockwise means that you are cutting less mids.

This is one of the reasons I would almost always dime the tone knobs on Marshalls when I played them. For me, it was the only way to get everything possible out of the amp. I always felt I was kind of "choking" some of the drive out of the amp when I would roll the knobs off a bit. I would basically just use the presence as a tone knob, and leave everything else sans the master volume dimed.

What are you playing? Almost all amps are passive tone stack setups same as a marshall.

 

[moronmountain]

First off, there is no active boosting. The TMB controls are passive and only cut the signal in particular frequency ranges. So, turning the mid pot clockwise means that you are cutting less mids.

This is one of the reasons I would almost always dime the tone knobs on Marshalls when I played them. For me, it was the only way to get everything possible out of the amp. I always felt I was kind of "choking" some of the drive out of the amp when I would roll the knobs off a bit. I would basically just use the presence as a tone knob, and leave everything else sans the master volume dimed.

What are you playing? Almost all amps are passive tone stack setups same as a marshall.

My other amps make alot more gain than my old Marshalls did when I had them, so that's the difference. I just thought the Marshalls had the most balls that they could have when I ran the tone section wide open.

 

[petejt]

First off, there is no active boosting. The TMB controls are passive and only cut the signal in particular frequency ranges. So, turning the mid pot clockwise means that you are cutting less mids.

Second, the conventional TMB tone stack used by Fender and Marshall (and many other amps) are highly interactive. Setting your mid pot will affect your treble too. More on that below.

Third, the rest of the preamp (and power amp and power supply) plays a big roll in setting the voice of the amp. The very low frequencies are filtered out, which is why a JMP sounds glassier and has less bass than a Fender. Amps will add higher-frequency harmonics, but you won’t hear 9kHz due to the guitar speaker.

So in considering this question, you can think of it in two ways:
1. how is the preamp filtering the signal at different stages? does the overall design give you lots of bass? Mids? Treble?
2. how is the tone stack designed? Separate follow-up questions would include: What frequencies are affected by the Bass control? The Mid control? The Treble control?
The tone stack on a JMP will give you a mid dip at about 800 Hz. So with treble and bass up and the mid set at zero, there will be a reduction of the signal centered at around 800 Hz. And when you rotate the mid pot clockwise, you add back frequencies in that 'range'. However, the TMB controls are highly interactive, so if you keep rotating the mid pot clockwise, you will start to boost the treble frequencies too. Also the centre frequency of the mid dip will depend on where your Treble control is set. If it is dimed, the mid dip will be centred at ~600 Hz. If it is at noon, the dip will be centred at ~800 Hz.

Thanks very much for this. The final paragraph is very interesting.

What happens to the mid dip if you set the Treble fully counter clockwise? Would the mid dip be centred at ~1kHz?

 

[V2a]

First off, there is no active boosting. The TMB controls are passive and only cut the signal in particular frequency ranges. So, turning the mid pot clockwise means that you are cutting less mids.

Second, the conventional TMB tone stack used by Fender and Marshall (and many other amps) are highly interactive. Setting your mid pot will affect your treble too. More on that below.

Third, the rest of the preamp (and power amp and power supply) plays a big roll in setting the voice of the amp. The very low frequencies are filtered out, which is why a JMP sounds glassier and has less bass than a Fender. Amps will add higher-frequency harmonics, but you won’t hear 9kHz due to the guitar speaker.

So in considering this question, you can think of it in two ways:
1. how is the preamp filtering the signal at different stages? does the overall design give you lots of bass? Mids? Treble?
2. how is the tone stack designed? Separate follow-up questions would include: What frequencies are affected by the Bass control? The Mid control? The Treble control?
The tone stack on a JMP will give you a mid dip at about 800 Hz. So with treble and bass up and the mid set at zero, there will be a reduction of the signal centered at around 800 Hz. And when you rotate the mid pot clockwise, you add back frequencies in that 'range'. However, the TMB controls are highly interactive, so if you keep rotating the mid pot clockwise, you will start to boost the treble frequencies too. Also the centre frequency of the mid dip will depend on where your Treble control is set. If it is dimed, the mid dip will be centred at ~600 Hz. If it is at noon, the dip will be centred at ~800 Hz.

Thanks very much for this. The final paragraph is very interesting.

What happens to the mid dip if you set the Treble fully counter clockwise? Would the mid dip be centred at ~1kHz?

The high frequencies drop out, so there is no mid dip; If bass is up high and the M and T knobs are at zero, you get a bass hump and ~100 Hz and a steady drop for higher frequencies. With treble on '1', the higher frequencies level out (that is, don't continue to drop), with the 'kink' in the curve at ~1100 Hz. You get a mid dip when the T is above '3'. At 4, the dip is at ~1000 Hz.

- All of this is influenced by the actual values of the tone stack.

- and keep in mind that if the preamp design filters out low frequencies with a cut off above 100 Hz (many high-gain amps do this), then having a TMB peak at 100 Hz won't matter much because there won't be any signal in that range....

 

[petejt]

First off, there is no active boosting. The TMB controls are passive and only cut the signal in particular frequency ranges. So, turning the mid pot clockwise means that you are cutting less mids.

Second, the conventional TMB tone stack used by Fender and Marshall (and many other amps) are highly interactive. Setting your mid pot will affect your treble too. More on that below.

Third, the rest of the preamp (and power amp and power supply) plays a big roll in setting the voice of the amp. The very low frequencies are filtered out, which is why a JMP sounds glassier and has less bass than a Fender. Amps will add higher-frequency harmonics, but you won’t hear 9kHz due to the guitar speaker.

So in considering this question, you can think of it in two ways:
1. how is the preamp filtering the signal at different stages? does the overall design give you lots of bass? Mids? Treble?
2. how is the tone stack designed? Separate follow-up questions would include: What frequencies are affected by the Bass control? The Mid control? The Treble control?
The tone stack on a JMP will give you a mid dip at about 800 Hz. So with treble and bass up and the mid set at zero, there will be a reduction of the signal centered at around 800 Hz. And when you rotate the mid pot clockwise, you add back frequencies in that 'range'. However, the TMB controls are highly interactive, so if you keep rotating the mid pot clockwise, you will start to boost the treble frequencies too. Also the centre frequency of the mid dip will depend on where your Treble control is set. If it is dimed, the mid dip will be centred at ~600 Hz. If it is at noon, the dip will be centred at ~800 Hz.

Thanks very much for this. The final paragraph is very interesting.

What happens to the mid dip if you set the Treble fully counter clockwise? Would the mid dip be centred at ~1kHz?

The high frequencies drop out, so there is no mid dip; If bass is up high and the M and T knobs are at zero, you get a bass hump and ~100 Hz and a steady drop for higher frequencies. With treble on '1', the higher frequencies level out (that is, don't continue to drop), with the 'kink' in the curve at ~1100 Hz. You get a mid dip when the T is above '3'. At 4, the dip is at ~1000 Hz.

- All of this is influenced by the actual values of the tone stack.

- and keep in mind that if the preamp design filters out low frequencies with a cut off above 100 Hz (many high-gain amps do this), then having a TMB peak at 100 Hz won't matter much because there won't be any signal in that range....

I have a Marshall head similar to the JMP, and going by your info will approach it a little differently. My aim is to get it to "growl" more, kind of like a Rockman sound but not as obnoxious or without having to use a wah-wah pedal to get that cocked-wah effect (even though I know that is key to that particular sound).

I suppose if you just crank the Midrange to 10, and use the Bass and Presence to darken the tone to suit, you could use the Treble to decrease the midrange centre frequency, as the knob is raised. E.g. Shift the midrange centre frequency from ~1kHz @ 4, ~900Hz @ 4.5, ~800Hz @ 5, ~700Hz @ 7.5, and finally ~600Hz @ 10. I do guess that it becomes a logarithmic scale as the knob is turned up.

 

[V2a]

I have a Marshall head similar to the JMP, and going by your info will approach it a little differently. My aim is to get it to "growl" more, kind of like a Rockman sound but not as obnoxious or without having to use a wah-wah pedal to get that cocked-wah effect (even though I know that is key to that particular sound).

I suppose if you just crank the Midrange to 10, and use the Bass and Presence to darken the tone to suit, you could use the Treble to decrease the midrange centre frequency, as the knob is raised. E.g. Shift the midrange centre frequency from ~1kHz @ 4, ~900Hz @ 4.5, ~800Hz @ 5, ~700Hz @ 7.5, and finally ~600Hz @ 10. I do guess that it becomes a logarithmic scale as the knob is turned up.

It's a bit more complex because these filters are so interactive. With Mids at 10 on a stock Marshall, you won't have much of a mid dip at all. With Treble at zero, then the frequencies even out at a pretty high level after 1kHz. With the Treble up to 4, the tiny mid dip is centered at around 600 Hz. When you lower the mids, the centre dip frequency goes up to a max of ~1kHz.

One thing is certain, however. With mids cranked, you get less attenuation of all frequencies. It is the mid pot (or resistor, if there is no pot) that sets the overall attenuation. If you mod your amp to have a higher-value mid pot, you get more signal through the tone stack (less attenuation). but at stated in the previous paragraph, with mids 'dimed' you get a pretty flat response.

 

[petejt]

I have a Marshall head similar to the JMP, and going by your info will approach it a little differently. My aim is to get it to "growl" more, kind of like a Rockman sound but not as obnoxious or without having to use a wah-wah pedal to get that cocked-wah effect (even though I know that is key to that particular sound).

I suppose if you just crank the Midrange to 10, and use the Bass and Presence to darken the tone to suit, you could use the Treble to decrease the midrange centre frequency, as the knob is raised. E.g. Shift the midrange centre frequency from ~1kHz @ 4, ~900Hz @ 4.5, ~800Hz @ 5, ~700Hz @ 7.5, and finally ~600Hz @ 10. I do guess that it becomes a logarithmic scale as the knob is turned up.

It's a bit more complex because these filters are so interactive. With Mids at 10 on a stock Marshall, you won't have much of a mid dip at all. With Treble at zero, then the frequencies even out at a pretty high level after 1kHz. With the Treble up to 4, the tiny mid dip is centered at around 600 Hz. When you lower the mids, the centre dip frequency goes up to a max of ~1kHz.[/quote]

That's okay. I'm not looking to dip/scoop the mids. I want to boost them! But in a particular range, and without sounding too spiky as that can thin out the rest of the sound. I'm just trying to better understand how to shift the centre frequency of the midrange (by setting the Treble knob down or up) and make that range more pronounced.

I am surprised that raising the Treble knob, actually lowers the centre frequency of the midrange. What is the frequency range/centre frequency of the Treble knob? The Presence? And what about the Bass knob?

One thing is certain, however. With mids cranked, you get less attenuation of all frequencies. It is the mid pot (or resistor, if there is no pot) that sets the overall attenuation. If you mod your amp to have a higher-value mid pot, you get more signal through the tone stack (less attenuation). but at stated in the previous paragraph, with mids 'dimed' you get a pretty flat response.

So does that mean, that the effect is diminished by cranking the midrange to 10, as that will just result in a flat response?

 

[V2a]

That's okay. I'm not looking to dip/scoop the mids. I want to boost them! But in a particular range, and without sounding too spiky as that can thin out the rest of the sound. I'm just trying to better understand how to shift the centre frequency of the midrange (by setting the Treble knob down or up) and make that range more pronounced.

Going from a scooped setting (mid knob at zero) to a more-or-less flat setting (mid knob at 10) has the sonic effect of boosting mids in the centre dip frequency (say 800-1000 Hz). If the treble is set high, the EQ won't be flat - there will still be more highs, and it might sound spiky and shrill. Try turning the treble WAY down (0-2) when the mid is set at 10. That will make the EQ flatter on the top end. In other words, to get the effect of boosting mids and not boosting mids and highs, you must turn down the treble as you turn up the mids. Those controls are very interactive!

I actually posted on this topic on my Facebook page, but nobody seem to care that much:
https://www.facebook.com/photo.php?fbid ... =1&theater

I am surprised that raising the Treble knob, actually lowers the centre frequency of the midrange. What is the frequency range/centre frequency of the Treble knob? The Presence? And what about the Bass knob?

There is no centre frequency for the treble knob; the way that the tone stack is designed, the treble knob passes everything above a certain cut-off frequency. With the mid knob at noon, that frequency is at ~1000 Hz on a typical Marshall.

Here is why:
Think of the preamp like a river in which the water (signal) can flow in different paths. In the tone stack, the first fork in the river takes part of the signal to the treble pot and part of the signal to the bass and mid pots. Just how much of the signal flows to the treble pot depends on a few things. One of these things is the treble capacitor (470p in a typical Marshall), which blocks the signal below some frequency (~1000 Hz). So those lower frequencies must flow in the other path to the bass and mid controls.

More on bass later...

So does that mean, that the effect is diminished by cranking the midrange to 10, as that will just result in a flat response?

It won't be perfectly flat in a stock Marshall. You will still have a bass hump and you can get more treble. As mentioned above, you can turn down the treble to flatten it out. You'll hear a mid boost with mid at 10 and treble at zero compared to mid at 2 and treble at 7, for example.

 

[mixn4him]

Download :
http://www.duncanamps.com/tsc/

You can go in and set values and move the knobs to see how the circuit will react...

 

[petejt]

Download :
http://www.duncanamps.com/tsc/

You can go in and set values and move the knobs to see how the circuit will react...

Thanks, but it doesn't have a version for Macintosh…

 

[petejt]

Revisiting this thread, I found out for Marshall amps:

Bass- 50 Hz
Midrange- 600 Hz
Presence- 2 kHz
Treble- 10 kHz