I've built the Anderton tremolo from the General Guitar Gadgets site, and it sounds great, but the problem I'm having is that it's eating batteries (two at a time), even when nothing is plugged in to the input.  I wired it as described on the site.  Is there a way I can make this pedal only on with input like my others.  What's throwing me off is the bipolar power.  Thanks.

No wonder it's eating batteries, you basically have it wired ON all the time!  GEO to the rescue!  Use the circuit from here (just the part inside the dotted line):

http://www.geofex.com/FX_images/splitter.gif

Here is a suggestion for future reference.  Consider adapting the circuit for a single supply.

I did just that with mine and it sounds great.  The interesting feature of this tremolo is that generally, there is not a lot of gain going on here.  A single 9v supply provides ample headroom for my personal guitar rig and pedal board.  

I do not have the schematic or my design files with me currently, but as I recall, I simply constructed a voltage divider to achieve a Vref of 4.5 volts and tied my Vref to pins 3 and 5 of the opamp instead of grounding those pins.  I further grounded pin 4 instead of providing a -9v supply.  The rest of the circuit is unchanged.  Of course, since I am talking off the top of my head, don't hold this out as gospel, but you get the idea.

There are a number of older effects out there that work fine on a single supply.  Just study the schematic and make the appropriate biasing adjustments and save the battery (and environment).

Best regards

Tom

That looks nice, except my BB size box is already full with the tremolo, especially since it has the two batts.  Is there any way I can do this with wiring, or maybe ditch one of the batteries and go 9V?  I really don't have room for another circuit.  Thanks.

Thanks Tom, I didn't see your post before my last reply.
-David

I agree. Change it over to a single supply circuit. I've done it with this circuit before and it sounds fine. Check out the Opamp-eration article on how to change it over.

Andrew