Treble bleed with linear 500k pot

[Sean92]

I wired in a 500k cts linear pot with my 500k audio tone pot. I love having control over my volume, never going back to audio ones again. I do have 1 issue.. treble bleed.

It seems pointless having a linear pot "dimed" all the time, I like to play at 7ish and I dime it when I'm trying to stand out during a specific part of a song. This means I'm dealing with treble bleed, its minor but its still there.

Treble bleed is tricky for me to figure out. Not having a resistor adds way too much treble to the sound at lower volumes. Having a resistor in parallel makes your taper match amount of treble bled through, which defeats the purpose of having a linear pot as well. A series set-up is the only way to go, but series is usually not as effective as the other two.

What combinations would be most effective? For a 250k audio pot, with my 10.5k pickups I found .0022 and a 51k in parallel to be most effective.. but changing to 500k linear has made this bypass mod useless as I mentioned above.

Any knowledge of treble bleed circuits? I could use some advice here

 

[line6man]

The best thing for you to do is invest in a cheap set of alligator jumper clips. They go for a few dollars at hardware stores and/or electronics stores, and will allow you to experiment endlessly, without the hassle of soldering and assembling/disassembling the bass. Try every desired combination of resistors and capacitors, until you find the perfect configuration, and then solder the chosen components in the bass, and be done with.

 

[Steve Dallman]

Start with a cap and resistor in parallel. I'd start with around a third to a half of the value of the pot, and a 470pF cap...maybe 220k. If too dark, go up with the cap, or if too bright, go down.

If you can't nail it, try a cap in series with a resistor. Here the cap provides the bleed, and the resistor pads down the action of the cap. Same values to start.

These circuits play with the resonant peak of the pickup, so experimentation is needed.

Another suggestion...If your tone circuit is wired to the pickup, try moving it from there to the middle/output leg of the volume. This with guitars is known as "50's" wiring. It makes the volume lose less treble when turning it down, but it does reduce what the tone does as you turn the volume down.

Values depend on the impedance of what you plug into.

 

[walterw]

Treble bleed is tricky for me to figure out. Not having a resistor adds way too much treble to the sound at lower volumes.

try a much smaller cap by itself, like .0003μF; for guitars at least, anything approaching even .001μF just makes it way too nasty for my taste when turned down. (actually i hate treble caps on my guitars period, and i work the volume for clean to crunch transitions constantly.)

It seems pointless having a linear pot "dimed" all the time, I like to play at 7ish and I dime it when I'm trying to stand out during a specific part of a song. This means I'm dealing with treble bleed, its minor but its still there.

why would it be a problem? strikes me that if your sound is dialed in so that "7" sounds right for regular playing, then if kicking it up to "10" makes it brighter too, that's what you want for your "standout" parts!

i still don't think this is the ideal way to approach passive bass though;

in general, your best, clearest tone is to be had with the volume dimed. on top of that, if the soundguy has you perfectly dialed in the mix with your bass at "7" and you jump it up to "10" it's just gonna send him scrambling for your channel fader before something blows up!

better to keep the volume consistent all night long (which diming the bass volume does automatically) then step on a tone-shaping pedal like an EQ or something, dialed to add mids and highs but not low end, so you can jump forward in the mix for a solo or whatever without wrecking the low end balance between you and the kick drum.

 

[Sean92]

Hello all, I'm back with some results. I tried the following combinations:

I've come to the conclusion that although these are acceptable values for the guitar world... they absolutely suck for bass.
.0012 + 130k in series
.001 + 150k in parallel
.001 + 130k in parallel
.001 alone
Not even going to bother describing them, just turn around and never look back.

These ones were mediocre:
.0022 + 51k in parallel (messes with taper)
.0033 alone (too bright at lower volumes)
.0047 alone (too bright at lower volumes)

These are pretty good, but not 100% there yet.
.00047 + 220k in parallel (messes with taper)
.00047 + 220k in series (treble bleed is still present)

I had the best results with these ones, couldn't tell them apart much:
.00025 alone
.0003 alone

But still not 100% there yet.

I also tried putting the wire that goes to my tone from the volume from the outside lug of the volume to the inside.. but it makes the volume and tone pot act weird.

I still haven't found the perfect values for my bass, but I think I'm done mixing resistors in parallel into the equation.

Sticking with caps or caps + resistors in series.

 

[rufus.K]

Does potentiometer taper really make a difference on the bass guitar? | eBass
Rothstein Guitars • Serious Tone for the Serious Player
Have any qualms about using an audio taper pot instead? Since your making a low pass filter with variable resistance, the "usual values" may not be working for you because with a linear taper pot, your not putting the resistance in the expected range.

 

[PawleeP]

I wired in a 500k cts linear pot with my 500k audio tone pot. I love having control over my volume, never going back to audio ones again. I do have 1 issue.. treble bleed.

It seems pointless having a linear pot "dimed" all the time, I like to play at 7ish and I dime it when I'm trying to stand out during a specific part of a song. This means I'm dealing with treble bleed, its minor but its still there.

Treble bleed is tricky for me to figure out. Not having a resistor adds way too much treble to the sound at lower volumes. Having a resistor in parallel makes your taper match amount of treble bled through, which defeats the purpose of having a linear pot as well. A series set-up is the only way to go, but series is usually not as effective as the other two.

What combinations would be most effective? For a 250k audio pot, with my 10.5k pickups I found .0022 and a 51k in parallel to be most effective.. but changing to 500k linear has made this bypass mod useless as I mentioned above.

Any knowledge of treble bleed circuits? I could use some advice here

Tried the series style treble bleed on a 500k Audio P volume and it made it markedly less linear. The parallel setup seems better so far, but you will prolly need to experiment with values based on your pickup(s) and preference.