Treble Bleed.............

[soulman969]

I popped the hood on my ASAT Special this AM to see what value tone cap was used and lo and behold I see another cap soldered to the volume pot in the same position a treble bleed would go but no resistor in conjunction with the cap.

If this is intended to be a treble bleed it's not a very effective one since the tone rolls off immediately and significantly as soon as the volume is rolled back. Can someone tell me just what they've done there? I can easily replace it with the same treble bleed I use on all of my Teles but before I do I wanted to know just what part that cap is playing in the circuit.

Thanks guys.

[DanDoulogos]

That's just a "simple" treble bleed. Running a resistor across (parallel) the cap is Duncan style treble bleed, and running it in series with the cap is a Kinman style bleed.



You probably know this, but I'll add this for the casual reader...

As you turn the volume down, more resistance is added to the circuit. As the resistance goes up, higher frequency signal is filtered out, when the volume is all the way "off" - it really has just filtering out all the remaining signal. What that means is that as the volume is lowered, tone is lost. To keep some of the higher frequencies in the signal as you increase the resistance (i.e. lower the volume), you include a capacitor across the leads to the pot. Since a capacitor acts like an open circuit at higher frequencies, it will allow some of those higher frequencies to "bleed" out into the amp as the signal is being choked out by the volume pot.

Putting a resistor across the cap - the "Duncan" style mod - lowers the (effective) resistance value of your volume pot (it becomes two resistors in parallel with a capacitor). Less overall resistance means the volume does not turn off as quickly as it would otherwise. That gives you more room for subtle volume changes - the cap just allows the treble to bleed through as this happens.

Putting a resistor in line with the cap, (the Kinman style mod) also lowers the effective resistance of the volume put, but shapes where and how the volume tapers off - more of a swell at first, etc.

if you just put a cap across the volume pot leads - you have a very simple treble bleed, not changing the effective resistance of your volume pot, so it'll taper off as per usual, but because the treble bleeds through as it is being cut off - the effect is more abrupt.

Hope that helps.

[soulman969]

Thanks Dan. I've always used the Duncan style and I've familiar with the second option (Kinman) and the differences but it's the first time I've ever seen it done without the resistor. You've answered my question and it's much appreciated. I'll just convert what I have to my usual method of installing one and I'm good to go.

Let me also say this is a great site and resource for tech info and other knowledge on these fine guitars. Experienced players helping neophyte G&L owners is what's it's all about and after all these years I'm pleased to finally be a part of a G&L owners community.

Thank you again for taking the time to respond so thoroughly to my question.