quick question about SHO

[egasimus]

Going simple since the missus won't let me devote time to the kind of projects that correspond to my ambitions
so I decided to build meself a SHO, and on vero, too I found the board completely by accident a while ago, I don't even like this build medium, but since it's such a simple circuit, I decided to give it a try.
So I have just a couple of quick questions about it and I'ma be on my way:

1. I see a 9V1 zener in some schematics. Would all hell break loose if I omitted it, and then power the circuit from 12V or so? (basically 9V@300ma unregulated)
2. A 10k lin pot in parallel with a 10k resistor makes a 5k log pot. Amirite?

[Suicufnoc]

1. Use the zener, it protects the Mosfet from overvoltage and really shouldn't be omitted.
2. Sort of.  I think you really want a 5k lin or 5k rev. log pot, but I'm thinking the parallel resistor might get you the Rev. Log taper you want in this case.

[StereoKills]

Definitely use the zener between Drain and Source, you risk frying your mosfet without it.

A nice read on pots (and their tapers) over at Geofex - The Secret Life of Pots
The section on changing a pot's taper to reverse log is at the bottom.
http://www.geofex.com/article_folders/potsecrets/potscret.htm

[davent]

There is an early SHO schematic that uses a couple 4148 diodes in place of the zener to protect the mosfet. However you do it, protect the mosfet.

http://analogguru.an.ohost.de/193/schematics/Zvex_SHO.gif

dave


edit:fixed spelling mess

[egasimus]

^ That's it! Thanks for pointing it out, this is what I'm gonna do.

[Joe]

FWIW an LED would probably work too.