Treble bleed circuit

[andyg_prs]

No regular pot goes completely open or zero, there will always be some resistance in 0-5ohm range that will let the bleed effect to be present barely on full volume, good news is that you need to be monitoring through a studio setup to actually hear that.

Anyways, 220pF is close to 180pF, which is what PRS uses. It should not give you a very prominent bleed effect as you roll down the volume. Check whether it's not 2nF, that would give you a very thin sound as you roll down, also check if you're using 50s or modern wiring scheme. If the parallel cap+resis setup was too much on the taper then try out the series cap+resis, it doesn't widen the taper as much.

Thanks - I'll check when I'm using a real amp at volume...this has been tested on my AX8. It's definitely 220pF....perhaps I made a mistake with the 100pF....I did test lots of times, but I'll look again. As I understand it though, the smaller the value.....the higher the frequency let through....so effectively it sounds brighter...




Can you tell the wiring scheme from this photo? Btw - the dull joints were there before I started!

 

[Hank-]

Looks like modern wiring to me from the pic. I am not sure about 1M ohms volume values & the value of treble bleed to go with, you might be getting a thinner sound due to that.

If ya gonna be removing that treble bleed cap in there now, you can try one quick variation, only unsolder the one leg of the cap on the middle lug of the volume pot and bend it all the t way owards the unsed lug of the tone pot, you can solder it or just bend it through the hole of the unused lug with tweezers. This mod will let you control the amount of the treble bleed using the tone pot. Just give it a try since it's a quick job and won't hurt anything either.

 

[eclecticsynergy]

a pot with a capacitor is a tone pot
but call it what you will

A tone cap rolls off treble by shunting it to ground.
A bleed cap simply lets some treble bypass the volume pot. No grounding involved.
The one in the vid has a bleed cap plus a trimpot to adjust the amount of bleed.

EDIT: What may be confusing is that the one in the vid is built into a pot, not a just cap & resistor kit.
But that's a replacement volume control.

 

[eclecticsynergy]

Hey guys,

I wanted to check something with you. I started with a 470 pf cap in parallel with a 220k resistor.....the sound still got much too dull as I started to turn down, so nowhere near enough trouble was bleeding through...but I was far more distracted with how the taper of the pot was impacted....almost no change in volume for the first 2/3 of travel.

So I went straight to just a 220pf capacitor alone. It works pretty well. But I would still allow more treble to bleed through ideally.

I went to 100pf, but even with the volume on full, it totally changed the sound of the guitar - it lost all the bass. So, for example, my lovely rich neck single coil no longer sounder like that, it was bright and thin sounding.

On a different forum I was told that my volume pot must be faulty. That when it is completely open, the capacitor should have no effect. Is that true?

Currently I've gone back to the 220pf capacitor alone.

Thanks,
Andy

Try a 180pF. It lets a little more through.

Another trait of a cap-only treble bleed is that it also affects the resonant peak of your pickups, making them sound more singlecoily as you roll back the volume. Very handy for humbuckers. Also the reason why bleed circuits for singlecoil guitars often use a cap/resistor network instead.

Many are unhappy with way a common cap/resistor/parallel bleed affects volume knob taper.
A cap & resistor in series as Hank suggested will be less troublesome. This is often called the Kinman treble bleed.

There is a third option which employs cap/resistor/parallel plus a very small value resistor in series.
I haven't tried it yet myself but Fender considers it superior and it keeps the taper very close to original.

Here's a link to a good comprehensive article including specs for a dozen bleed circuits listed by manufacturer.
https://stratocasterdesign.com/index.php/treble-bleed/

 

[Teleplayer]

Seems like you have it sorted with the simple 220pF cap. It should have the code "221" on it, to identify the value, but I had trouble viewing it in your photo.

The parallel resistor config is normaly used with "Audio taper" (a.k.a. LOG) pots. I guess your guitar may have a "Linear taper" type, which is likely to have the issue you mentioned.

Generally the larger capacitor will give increased boost of high frequencies, but too large a value will boost the mids as well as highs. That's why its hard to find the right value.

Another complication with choosing the capacitor value, is the treble bleed is dependent on the guitar cable you use. Eg. if you swap a 20' cable to a 10', it will make a bigger difference than changing the treble bleed capacitor value by 100pF. Changing to a wireless system would be another matter again, and not so easy to predict.

 

[andyg_prs]

No regular pot goes completely open or zero, there will always be some resistance in 0-5ohm range that will let the bleed effect to be present barely on full volume, good news is that you need to be monitoring through a studio setup to actually hear that.

Anyways, 220pF is close to 180pF, which is what PRS uses. It should not give you a very prominent bleed effect as you roll down the volume. Check whether it's not 2nF, that would give you a very thin sound as you roll down, also check if you're using 50s or modern wiring scheme. If the parallel cap+resis setup was too much on the taper then try out the series cap+resis, it doesn't widen the taper as much.

Thanks, what concerns me is that with 100pF the effect of the capacitor (the neck single coil losing nearly all of its bass / characterstics) is very very noticeable, with the guitar on full volume.

I guess this statement is either wrong or over simplified? https://stratocasterdesign.com/index.php/treble-bleed/ Treble bleed mod has NO effect on your guitar tone when the volume pot is on 10 as the capacitor (and its resistor if present) are short circuited.