Converting the SHO design to be used as a buffer?

[wormfooduk]

I really like the sound of the SHO with my US telecaster, im not sure what it does but even with volume set so that its level with the bypass signal, it seams to really meat up the single coils. its the version with the 10m resisters and the zener diode in so i guess its just giving the guitar pickups a better impedence to work with. Anyway what do i need to do to the circuit to convert it into a buffer that i can build into other designs. 

[jkokura]

Remove the knob and use one resistor to set the gain to unity? Or use an internal trimmer to set the gain?

One thought - why don't you try building a Buffer using the 10M input resistors - it might get you that sound?

Jacob

[wormfooduk]

the fet has to have something to do with it 

Anyway thanks. ill give it a go.

[earthtonesaudio]

The only way I can see to make a SHO into a "good" buffer without adversely changing the sound is by adding a buffer to the output.  If you're using it at unity gain you don't need anything special, just a voltage follower.  Can be another transistor or an op-amp.

[DougH]

In general, common source MOSFET stages make poor "buffers" because they have a high output impedance. The definition of a "buffer" is a stage with roughly 1x gain that drives a lot of current. In other words, low output impedance. If, on the other hand, you're just looking for a low gain preamp that gives you the sound of the SHO, then follow the other suggestions about using a fixed resistor to set it to the gain you want.

[R.G.]

See: http://geofex.com/Article_Folders/mosboost/mosboost.htm

You can get a buffer by simply taking the output from the source. You can get an inverting buffer by taking the output from the drain if the source and drain resistors are equal. In that case, the output impedance is about equal to the drain resistor, and that's usually 5K to 10K, typically close enough for buffering in pedals.

[wormfooduk]

Thanks for the info ill have a read