General tech questions

Anti-mud Switch


On my '59 Single Anniversary I'm looking to use one position of the tone switch to roll off the lows so that the output of the guitar is left with just the highs.

Any suggestions for component types and values?


Mud switch is a low pass circuit. Use the same cap value in a high pass circuit.


For High pass you would generally use a coil or choke instead of a capacitor.


I'm not sure there are enough throws on a mud switch to do it and a low pass, but a series capacitor would give you a high pass.

I'd recommend putting the circuit on its own pot. Look up the bass contour circuit on the Reverend Pete Anderson. It's super useful.


Was hoping for something passive that would 'bleed' bass to ground in a similar manner that a cap 'bleeds' treble to ground. Not so simple without losing significant volume I fear, but I'll try calculating what size inductor coil and trimpot I can get away with to bleed off bass, thanks to all for your input! If I get it working to my satisfaction with the guitar still looking stock I'll report back.


That's exactly what the series capacitor does! Bass will "bleed" through the volume pot.

You don't need inductors or trimpots.

Try it outside the guitar, I think you'll be impressed.


You could have a look at Joe Gore's "ToneFiend" site, which has quite a lot on bass-cut mods to guitars.

The wiring is a little different - rather than bleeding off to earth, the signal simply goes through the capacitor on its way to the output jack.

The value of the caps will differ from a treble cut (i.e the standard cap you'll find), which would generally be a '473'/0.047mF for a Strat, and a '223'/0.022mF for a humbucker.

For bass cut, you're going to need an 'XX2' value cap - say '222'/0.0022mF - note the extra '0' after the decimal point.

I made a little remote box with four values in, which could be switched in or out. Values I went for (based on availability of generic components) were: '472', '332', '222' and '152'. The smaller the number, the greater the bass cut. The '472' is so subtle that it's possibly of little use as an overt 'effect', tone-wise. The other three I had put onto a four-position rotary (position 1 direct, then 332, 222, 152 to increase the cut), and plan to put it in a guitar one day...

Have a read here, Joe Gore's stuff for Premier Guitar. Includes this circuit, with 'real life' diagrams showing parts with wires between, rather than schematics, and a table of cap values on one of the latter pages.



The wiring is a little different - rather than bleeding off to earth, the signal simply goes through the capacitor on its way to the output jack.

While your post is very helpful, this line isn't exactly true. The bass is being bled to ground, it's happening either at your volume pot, or at the grid resistor of your first gain stage, depending on where you put the capacitor. You can't have an RC filter without the R, it's just a little harder to see in the high-pass scenario. This is why the cap values in your mod are different, because they're calculated based on a different resistor.

Anyways, the mod you suggest is really useful, and I recommend it to OP. It's just, because of the design of the switch, you can't do it using a mud switch. Best I can figure, you would need a single pole triple throw switch, so that you could break the center connection when you want the series cap in the high-pass position. If anyone can figure a way to do this with the existing switch, I'm all ears.


I've no doubt you're correct - I was posting from memory, and a starting point of ignorance about electronics. Thanks for chipping in.

That said, the little box I cobbled up was an interesting toy to play with. I used a couple of Fender Mustang three-position slider switches with the central position as direct, and each of the 'throws' to add in a different capacitor.

I also added a blend pot, which was switchable in or out via a Fender Jaguar-type two-position switch, but in practice the on/off switch was fine on its own.

I came at it from the Gibson varitone, which seemed to have a rotten selection of values, The only video I saw of it producing useable tones were from a guy playing a cream SG - I worked out that every time he changed the Varitone, he was adjusting the tone controls to 'offset' whatever effect the Varitone had (fattening up the thin sounds, brightening up the dull ones).

The notion of a four-position variable bass cut came out of the box, and owes a lot to Joe Gore's article, and the videos on his own site.



There needs to be a way to increase Gain while decreasing Bass. No doubt a passive circuit can be wired to be high pass, but so much energy will be lost otherwise.

I think of what happens on my Hi-Fi set-up Equalizer, the sound can get really thin.

But, then again if you choose that sound, just turn up the amp Volume...and never touch the Tone Control unless you want the Bass roaring back in.

Have you tried a "Nashville" set?

EXL150H d'Addario...

Cannot post pics on the site at the moment, Google it.


hmmm...not sure I want to lose the character of the guitar as it is by changing strings! I just want to find a way to dump some of the bottom end out of the tone by using one position of the 3-way tone switch. Pretty sure it's just a SPDT switch but my memory is foggy on that, if it has other unused contacts that allow a series cap for the signal then I'll use them, or perhaps go hunting for one that does but still retains the same toggle thread.


"Nashville" string sets have been around a long time, the one I highlighted is for Electric guitar.

Give a set a try, I think it is the sound you seek....≤$5?

They even make "Nashville" braced acoustic guitars.

They have a 12- string sound without the jangle...and you will have a root note already an octave higher.


Sure sound like an interesting way of stringing the guitar - thing is I only want to drop the bass out in one setting, I like the tone already of the straight guitar sound and the mellow sound on the other switch position. It's just that I want to drop out some bottom end on the third switch position. Those strings would mean I lose the straight sound of the guitar, which I love, so switching the tone switch isn't gonna bring that back...perhaps I just need to get real fast at changing strings mid-song!


You can always just add another neck onto that Annie!


Thanks Hofner, I have seen that before - it's a series circuit which should work fine on those type of guitars, but I'm looking for a 'shunt' circuit due to the type of switch used on the Gretsch. What I want is to leave the guitar looking stock, not add extra switches or pots. I'll be visiting a supplier today to look for some inductor coils and/or cores to do some test winding. Not sure how successful I'll be as I haven't done the maths.


Okay - just re-watched this one, thought I'd post it for anyone else who's interested:

seems to be plenty to investigate.

Hope you get a good mod out of it. Do consider a remote hobby box try-out like I did - you might find a combination that nails what you want.



Ok I've got it working now, instead of a 'passive treble cut' on both sides of the tone switch I now have 'passive bass cut' wired into one side using a small audio transformer to shunt low frequencies to ground. Hot-glued the little fella to the underside of the switch assembly.


Cool mod, Doppler. What value transformer did you use?

For the record, another bass filter option is the Fender Jaguar "thin switch", basically the cap mod described above. I added it to my Jazzmaster. The bass tone control is also cool, I installed that in an HSS Strat for a friend.


...or you could get an EQ pedal.

– wabash slim

I don't like adding stuff like modern pedals in the signal path. Thanks for the suggestion WS, along with your previous idea of modifying the guitar with a series cap but that is too much trouble for me to bother with...different type of switch required etc...quick & dirty is my thinking, and an easy mod to reverse later.


Thanks Mel, I used a little 3k-3k miniature audio transformer. Series cap is always an option but in this case I didn't want to re-wire the whole guitar to put a series cap in, just wanted to shunt low frequencies so it's an easy one to adapt to the existing switch.


All you need is a small capacitor in series with the signal. Inductor coils are for low pass. Start with a .001 or .005. It all depends on how much low end you want to cut off. Caps are cheap, but for this use a good quality film type, like $1 each.


Put the cap in series, and use the switch to bypass it in all but one position.


Thanks for the suggestion Billy, I was thinking again about how to do this just yesterday. Tricky with the existing switch as I pointed out above to the others who suggested a series cap. Regarding inductor coils being low pass, that's the rationale for using one as a shunt.

I want to retain 3 different sounds in the 3 switch positions and don't want to change the switch out for another type, or re-wire the guitar, at this stage. The switch is SPDT CO, so bypassing a series cap in 2 of the 3 positions results in the same sound in those 2 positions.

If there was a more versatile type of switch available that looks the same I'd love to know about it. Perhaps there are other switch types fitted to modern Gretsch guitars?

For now I'm going to play around with the existing little transformer - currently I'm only using one winding so I'll try both primary and secondary in series with each other and see if that gives a sharper roll-off of the low frequencies with less treble volume loss.

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