Guitar Treble Bleed Circuit Diagrams

[WGTP]

http://www.aronnelson.com/gallery/main.php/v/WGTP/Treble+Bleed.GIF.html?g2_imageViewsIndex=1

I put this together for the Seymour Duncan Pickup Forum, but it would be a part of the circuit when your guitar is plugged into your favorite distortion box.

It basically effects the treble loss/boost as the volume knob is turned up or down.   

[John Lyons]

Cool. thanks for posting that.
It's a nice circuit to add to some pedal circuits that get
too dark when turned down.
John

[scottosan]

http://www.aronnelson.com/gallery/main.php/v/WGTP/Treble+Bleed.GIF.html?g2_imageViewsIndex=1

I put this together for the Seymour Duncan Pickup Forum, but it would be a part of the circuit when your guitar is plugged into your favorite distortion box.

It basically effects the treble loss/boost as the volume knob is turned up or down.   

It would not serve as a boost when turning the volume up.  When the pot is turned all of the way up, the woe lugs will have 0 resistance rendering the resister and cap completely out of the circuit.  This is common in many guitars .

[chi_boy]

This is interesting.  I've been mulling this mod over as I have been rewiring my strat.

I need a little help with the math on the Seymour Mod.  With the pot set at maximum volume, the cap/resistor are shorted out and don't change anything.  At minimum volume though, isn't the actual resistance calculated as 2 resistors in parallel?  So for a 250k pot set at minimum volume, the actual resistance would be 250k parallel to 100k or a net Resistance of ~72k.  Or am I thinking about this the wrong way?

Obviously the Seymour Mod has been around a long time and is used by many, but the math just strikes me as odd.  I'm just wondering if I have it straight in my head.

George

[scottosan]

This is interesting.  I've been mulling this mod over as I have been rewiring my strat.

I need a little help with the math on the Seymour Mod.  With the pot set at maximum volume, the cap/resistor are shorted out and don't change anything.  At minimum volume though, isn't the actual resistance calculated as 2 resistors in parallel?  So for a 250k pot set at minimum volume, the actual resistance would be 250k parallel to 100k or a net Resistance of ~72k.  Or am I thinking about this the wrong way?

Obviously the Seymour Mod has been around a long time and is used by many, but the math just strikes me as odd.  I'm just wondering if I have it straight in my head.

George

Don't take my word for it, measure it out.  When the volume is full on a 250k pot, the ther is 0 resistance between lugs 1 and 2, and 250k between lug 2 (hot) and ground. Zero ohms in parralel with any value will always be zero.  When the pot is turned all of the way down their is zero resistance between lug 2(hot) and ground thus no volume. regardless what value resistor and cap you use between lus 1 and 2, they will have no effect on the circuit when the volume is turned all of the way up.

[John Lyons]

Just a note that the hot lug (full Clockwise) is lug 3 not lug 1.
When the pot is turned full CW, lugs 2 and 3 are shorted together,
no resistance (or very little).
But yes, it's as scottosan describes.

[chi_boy]

OK, so I did as suggested and pulled out a 250k pot and a 100k resistor.  Soldered the resistor as shown in the Seymour Mod, between the hot and the center.  At full CW (viewed from front of pot) the resistance between the hot lug and the center lug was .3ohm and the resistance between the hot lug and ground lug was 275k.  At full CCW resistance between the hot lug and the center lug was 73.8k and the resistance between the hot lug and ground lug was 73.8k.

Still can't get my head around it.

[BAARON]

That is correct, chi_boy.  Now, measure from the center lug (output) to the ground lug, and you'll find that they're connected.

Another trick that reduces treble loss as you roll down your volume is to simply attach the tone controls to the middle (output) lug of the volume pot instead of the input lug.  (It essentially changes the placement of the tone control in the circuit when the volume is turned down.)  I find that it makes a big difference and keeps your tone clear, but without the skinny/bright sound you start getting when the volume is turned down with the brite caps added to your volume pot.

[stallik]

Yeah, I know this is an extremely old thread and, as my ISP forbids connection to the layouts gallery, I may be repeating what's been said already but..

Tried this treble bleed on one guitar then spent the last evening adding it to all of them. Best I've heard yet - think it's pretty close to what Fender are currently fitting to American Strat's & Tele's. Doesn't seem to loose any frequencies (to my old ears) just gets quieter

[iainpunk]

i used to have it on my explorer, untill i replaced all the electronics, and forgot to put it back. mine had different values tho, it left the treble at full volume and just cut the bass for the first half turn, then it quieted down everything.
really cool to use with fuzz and muddy distortion circuits

cheers

[stallik]

My values probably won't de mud a fuzz, the bass/mid/treble balance remains pretty constant. That's what I like about it.

[ashcat_lt]

This is a pretty old thread, but only slightly older than JohnH's thread over at GuitarNutz where he compares various types of treble bleed circuits, which some of you might find interesting.