Klon Buffer and Op-amp Biasing

[Blenji]

I like the sound and feel of the Klon Buffer (schematic below), but want to give it more headroom. Am I right in thinking that it's as easy as running a +9/-9 to the opamp, then the ground from R2 to -9 to give a vBias of 0v, that that will do the trick? Or would the ground of C1 also have to be tied to -9?



Many thanks.

[Mark Hammer]

The buffer in the Klon and some other pedals (e.g., the Visual Sound Truetone, and Catalinbread EP booster) use "charge pump" devices to increase the supply voltage, and improve headroom.

Charge pumps work by producing a high-frequency pulse with the incoming supply (generally +9v), and then summing those pulses in some fashion to provide other supply voltages, such as +/-9v or even higher. For example, see here: New Page 1

One of the advantages that such an approach provides is that one can still uses the same old +9v wallwart or brick supply, and do other "tricks" with it. This is particularly handy when a circuit requires a +/- supply and there is no easy means for turning the batteries off when not in use.

The schematic you show uses a "floating ground" provided by dividing the single-ended supply in half. You could provide higher supply voltages and divide those in half in a similar manner.

The caveat is that charge pump chips are somewhat limited in how much current they can provide. That won't be an issue for a unity-gain buffer where current requirements are minimal.