English Muff’n tone controls

This topic has 19 replies, 3 voices, and was last updated 13 years, 9 months ago by Led Hendriani.

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June 21, 2010 at 3:39 am #80383

inPlexicated
Member

Initially I was kinda disappointed with how the pedal seemed on you tube clips.I was really hoping it would have that raw Hi-Watt/Marshall thing but the treble range is so thin and harsh.

2 years later I decided to see if there were new clips and there are-which is a good thing!

In 2 of the newer you tube videos you see that the users keeps the treble way way down which makes the pedal sound “normal”(useable) NOW it sounds freaking BRILLIANT!

In my estimation 65% of the high pot’s sweep is unuseable.Once the control get past 11’oclock it sounds like everything in the 2-3+kHz range is boosted by a billion db’s LOL! Its so bright that it makes a Dr Z MAZ seem a bit dulll.

Why is it so exaggerated? Is it because how the tonestack is placed in the circuit? or is it the capacitor value around the high pot??

SO my question is– Can the pedal be modded to tame the treble control??

I like clang and chime too but it would be nice to have the control to be able to be useable above just a 1/4 of it’s turn…there is always a brite switch option….

Me thinks some frequencies need a bit more shunting to ground -if you know what I’m saying.

Great pedal none the less!

EDIT: It could be one of the best tube pedals ever made but people are being turned off by the high control it’s too anti-intuitive.You could be selling WAY more of these things if you changed it.

June 21, 2010 at 10:57 pm #109698

julian
Moderator

Well if only part of the range of the pot is useful to you, then you could replace the pot with a different value.

Looking at a schem, I see it’s a 250k linear. I think you want to change potentiometer type to either logarithmic or reverse logarithmic. Changing the value might help as well.

I just googled the schematic and took a peak at it.

You could also mod the tone stack as a whole to be an exact copy of the Marshall tone stack (it’s very similar, but slightly different, if the schematics I’m looking at are correct.) I have to go right now, but I can describe the differences in a little bit.

June 22, 2010 at 5:45 am #109701

julian
Moderator

Hey, I’m back.

Check this out:

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

This program is a tonestack calculator. It takes popular tone stacks and calculates the EQ curve for them.

The English Muff’n indeed uses a Marshall Tone Stack, but the values are tweaked.

Here’s the Marshall Tone Stack:

(note, treble pot is linear, bass pot is audio (reverse logarithmic), and mid pot is linear.

Now here are the values for the English Muff’n (according to the schematics I found):
R1: 30.1 k
R2: 250k linear
R3: 500k log
R4: 10k log
R5: omitted
C1: 220p
C2: .1 u
c3: 22n (unchanged)

Of course, remember that the intensity of the treble will also relate to your mids and bass settings.

Replacing that 220pf cap with a 470 pf cap might just do it.

June 22, 2010 at 5:46 am #109702

inPlexicated
Member

Quote:

Well if only part of the range of the pot is useful to you, then you could replace the pot with a different value.

Looking at a schem, I see it’s a 250k linear. I think you want to change potentiometer type to either logarithmic or reverse logarithmic. Changing the value might help as well.

I just googled the schematic and took a peak at it.

You could also mod the tone stack as a whole to be an exact copy of the Marshall tone stack (it’s very similar, but slightly different, if the schematics I’m looking at are correct.) I have to go right now, but I can describe the differences in a little bit.

Thank-you for responding yes I have the schem now.I went to freestompboxes.org as another admin suggested.There was exceptionally good info there.If you happen to know the more typical Marshall values and you care to post i thank-you in advance.

June 22, 2010 at 5:54 am #109703

julian
Moderator

one other thing you might want to do is experiment with different 12ax7/7025 variants.

June 22, 2010 at 5:59 am #109704

inPlexicated
Member

Quote:

Hey, I’m back.

Check this out:

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

This program is a tonestack calculator. It takes popular tone stacks and calculates the EQ curve for them.

The English Muff’n indeed uses a Marshall Tone Stack, but the values are tweaked.

Here’s the Marshall Tone Stack:

(note, treble pot is linear, bass pot is audio (reverse logarithmic), and mid pot is linear.

Now here are the values for the English Muff’n (according to the schematics I found):
R1: 30.1 k
R2: 250k linear
R3: 500k log
R4: 10k log
R5: omitted
C1: 220p
C2: .1 u
c3: 22n (unchanged)

Of course, remember that the intensity of the treble will also relate to your mids and bass settings.

Great! thank-you I appreciate the effort.

I’m wanting to attenuate or change the frequency centre of the treble.So I assume you are suggesting in doing so it will lessen the effect of the corresponding controls?

Why do you think EHX decided to go with the values it did knowing the treble would shear shingles off a house?

Cheers!

June 22, 2010 at 6:18 am #109705

julian
Moderator

You know, I’m not sure. . . I’m still learning about this stuff myself.

One thing you have to consider is that people all have different guitars, different amps, and different cabs.

Your setup may be relatively bright and you might not need so much of the treble. Someone else might have a very dark amp/cab/guitar combo and need more.

Or sometimes people like to run effects chains in parallel and blend. Sometimes a lot of treble is beneficial. You can get some really great dirt tones with heavy treble in one parallel chain, and a really thick bassy distortion in the other.

June 22, 2010 at 6:31 am #109706

inPlexicated
Member

Yes actually I remember seeing that tonestack calcualtor before but forgot the address thanks-its a cool visual aid.

By “Marshall” tonestack you mean a cathode follower design?

Strange they chose the linear instead of a log.did they want to avoid copyright infringemnet? I figured that circuit has long been public domain.

The log pot works with how our ears work right? The linear pot sounds like it should work the way it sounds “increasing signal in a linear way” and it does, but it’s the whole db thing and our perception right?

looks on paper Vs how we really experience it.

IT would seem just changing the pot type would do it.The cap values may differ giving a different sound(than the marshall) however it was smoothing the treble contour is all thats needed.What would a reverse log do?

G

June 22, 2010 at 6:57 am #109711

inPlexicated
Member

Quote:

You know, I’m not sure. . . I’m still learning about this stuff myself.

One thing you have to consider is that people all have different guitars, different amps, and different cabs.

Your setup may be relatively bright and you might not need so much of the treble. Someone else might have a very dark amp/cab/guitar combo and need more.

Or sometimes people like to run effects chains in parallel and blend. Sometimes a lot of treble is beneficial. You can get some really great dirt tones with heavy treble in one parallel chain, and a really thick bassy distortion in the other.

I know what you mean about set differing set ups.But this type of consumer product people expect a balanced control function.I think it would have been extremely popular with people had they stuck with the classic circuit

I’ve used a treble booster for the last 25 years for the usual reasons.

One of my newer amps is a Dr Z Z-28 and it like pretty much all Z amps are very bright.Using a noramlly voice pedal still requires high-end attenuation.

The English Muffin’s high control is like no other pedal or preamp I’ve ever encoutered.Maybe it’s like an original tweed Bassmans after all it’s where the cathode follower design was first employed in a music amp.It’s treble control is like shattering glass too.

Now I know why,due to the values and the “lin pot” it’s literally doubling the treb in comparison to most amps.

Well at least now I can feel confident about purchasing one and changing the pot and maybe a cap or 2.

G.

June 22, 2010 at 6:12 pm #109729

julian
Moderator

I’m doing some graphing with Duncan’s tone stack calculator right now, and I tried a couple things:

at about 1/4 of a turn on a linear treble pot, the upper end of the treble is at about -10db. (let me mention that the tonestack is subtractive, it doesn’t boost frequenciess, it just subtracts them. All the way to the left it subtracts the most)

If I switch that to a logarithmic, it doesn’t hit -10 dbs until 1/2 of a turn. reverse logarithmic does even better, with it not hitting -10 dbs until 3/4s of a turn.

Increasing the 220n capacitor to 470k actually adds treble (and high mids.) I think one substancial difference with the Marshall tone stack is that it doesn’t scoop the mids as much. So while it adds more treble, it adds more mids, thus it sounds more balanced.

June 22, 2010 at 6:31 pm #109730

julian
Moderator

Here’s a graph:

cool colors are the Marshall tone stack, hot colors are the Muff’n tone stack.

The curves with less treble have every potentiometer set half-way. The curves with more treble have every potentiometer set half-way except for treble, which is cranked.

I can see why they designed it like this. They improved the bass response, which is generally something want more of nowadays, and they cut the mids more, perhaps to make it a bit more Muffy.

I think to tame the treble the best thing would be to change the pot to reverse-log 250k, and change the mid pot to 25k linear. This will also as a byproduct make it less scooped.

What I’d also do (and this is just me) is add a “bright” switch to add a 250n or so cap in parallel to the 220n cap to bring it to the typical Marshall spec and had some high-mids as well.

I’d tone down the EH .1u to the Marshall 22n and have a switch to add a 78n or so cap in parallel as a “bass boost” switch.

Increasing the mids cap increases the mid-scoop, but also lowers the center frequency of the mid scoop and lowers bass. So you could find a cap value you like as far as mids go, and then add a mid scoop switch that would wire another cap in parallel too.

If you wanted to, you could also add a tone-bypass switch.

June 22, 2010 at 9:24 pm #109735

inPlexicated
Member

Hey Julian,

Looks like the graph is a casualty.Thats okay though I’ve been looking at all the “curves”.I can see the scoop of the BMP and perhaps you’re right,maybe they decided to have a somewhat traditional product sound “Tube Pi” lol!

Yes being a passive tonestack it’s all subtraction without the triode powering the signal there wouldnt probably be much of a signal at the end left even with the pots turned all the way up.

The Bass is muddy (useless) after 1 o’clock so boosting it was pointless.The pedal wasn’t aimed at the heavy metal crowd.All they did was frustrate the consumer who desired classic rock tones -which by the config and graphics is the consumer it’s focussed on.It’s not a tube version of the Metal Muff.

Yes your idea for revisions are good.I also had thought of having switches to add or subtract values giving added flexibility.

The suggestion for tone by-pass actually maybe the best.That way not only is there less tonal degredation,I choose how I get to condition the signal’s EQ.I could also install a switch to add or remove a gain stage too.

I already intended to make a project of this.I think what I’m going to do is create a bank of tonestacks on a board and experiment on values.

“I love the smell of solder in the morning”

Again thanks bunches for your efforts Julian,you’ve helped tremendously,

Graham.

June 22, 2010 at 9:56 pm #109708

julian
Moderator

hmmm I forgot to put the graph up!

Haha!

Here it is:

June 22, 2010 at 10:02 pm #109709

julian
Moderator

But anyways, there’s tons of different combinations of pots and caps you can use, and they all interact a bit if you futz with it in Duncan’s calculator.

June 23, 2010 at 1:42 am #109741

inPlexicated
Member

Quote:

But anyways, there’s tons of different combinations of pots and caps you can use, and they all interact a bit if you futz with it in Duncan’s calculator.

Yes I know the permutations are endless…..

In a month I’ll be sitting on the floor of a white padded room, rocking back and forth with a laptop doing “final” tweaking :freak:

BTW do know if they make dual ganged linear/log hybrid pots? I’ve googled a bit..

Graham
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