Neutron Filter Chokes and wiring question--getting rid of the 10K whine....

[celamm]

I've built the general guitar gadgets version of the "Neutron Filter" Mutron III clone.  I have it working, except I have a 10K whine at the output.  http://www.generalguitargadgets.com/index.php?option=content&task=view&id=135&Itemid=149 

I am not using batteries.  Just a 9V DC wall wart.  I am using the 7660 based charge pump as shown on the ggg schematic.

I have wired it so the + from the wart goes to "batt +" on the pbc, the ground from wart to the "batt -" and the ground from the input/output jacks to the "input stereo" side of R20.

Is this the best practice for wart hook up?  I cannot find much information about wiring this with a 9V DC wart, the 7660 in place, but without a battery.

Next question: to get rid of the whine the text on the ggg site talks about using chokes instead of the the jumpers in the 7660 area of the PCB.  Can someone suggest which chokes to use?  I see plenty on Mouser's site, but most look to be in the RF range.  If possible the choke would have to be small enough to fit on the PCB, or at least inside the enclosure.

I have zero experience with chokes so any suggestions on the best chokes to use would be appreciated.

Thanks in advance for any help....

--CL 

[R.G.]

A very simple and effective way to get rid of the whine is to replace the 7660 with MAX1044 or an LT1044. They are pin-for-pin compatible. These ICs run at a "whine" frequency that is above the audible range, so they cannot make audible whine when set up as in this circuit.

The 1044 is probably cheaper than two inductors, too.

[celamm]

Thanks RG I have purchased a few 1044's from smallbear and will give this a try....

A very simple and effective way to get rid of the whine is to replace the 7660 with MAX1044 or an LT1044. They are pin-for-pin compatible. These ICs run at a "whine" frequency that is above the audible range, so they cannot make audible whine when set up as in this circuit.

[celamm]

OK, it's in, whine is gone. I had to hook pin 1 of the 1044 to the 9V rail by soldering in a tiny bit of jumper wire.  I read this makes the whine frequency go up out of hearing range.

I am having some other issues which I'll post separately.  But this build is getting close to working!!