+/- 9v supply

[col]

I am propsing to use the layout as suggested by R G Keen to supply +/-9v to a build. I can only get the 7660 Ic so need to keep the whine out of the circuit. Looking at the web page that shows this are the two connectors on the jack socket shown correctly as the stereo lug that would connect the second ring on astereo jack is shown as signal. I thought that this should be the jack tip. I might be missing something obvious here and apologise if this is the case.
Alternatively, what value of capacitor would remove the whine produced by a 7660 chip?

Col

[zachary vex]

R.G. has instructions on his site to help reduce the whine using a battery switching trick to keep ground noise to a minimum.  the connection used is the ring connection (not the tip) which will short to the ground connection when a standard "mono" plug is inserted into a stereo jack.

you may be able to eliminate the whine from a standard 7660 chip for an effect that doesn't have high gain, but i think you'll want to get a MAX1044 (using whatever method necessary... perhaps ordering from small bear?) to raise the whine out of the human hearing range.  i've done quite a number of experiments with these chips and i will strongly recommend that unless you've had a lot of experience elminating noise, you may be very very frustrated using a non-MAX1044 as your power supply chip... especially in a high-gain pedal!

[col]

Thanks for that. I copied the supply part of the circuit from RG Keens NewTron off Geo which uses a 7660 chip. Has anyone used this and did it filter the whine out? I have looked for a UK supplier of a MAX1044 and haven't been able to find one. I will make provision for a dual battery supply just in case!
In the NewTron info he says that if whine does occur it can be filtered out using a cap, any ideas of cap values?
The pedal I am proposing to use it in is a 'woody'. As far as I can see there is only one part of the pedal with high gain which seems to be a treble exiter. I'll have to try it and see.

[Paul Perry (Frostwave)]

I believe the ICL7660 can be overdriven by an external clock.
So if you have a 555 timer to spare, you can run that in the ultrasonic range & shift the noise up. (see the ICL7660 data sheet for details).

[Mike Burgundy]

That's right Paul, it can. Works a charm!
7660 plus 55 plus peripherals are a LOT cheaper than a 1044...

[col]

I just noticed that the IC I ordered is the ICL7660SCPA which according to the spec sheet also has the increased oscillation facility of the MAX1044 by connecting pin 1 to +v. I've already cut the pin 1 off the ic socket and soldered it to the board so I'll just have to desolder and replace it and try it out. The spec sheet also shows you how to overdrive the oscillator off pin 7 using a timer so if the pin 1 scheme doesn't work I'll try that.

Thanks for the info.

[PaulC]

I was talking to a guy about a year ago that was in the aerospace field and did things like made the boards that went into skylab gear.  We were talking about this stuff and he had a great idea to help shield the chips.  Use a double sided pc board with plated through holes.  Build the pwr supply in one area and then build a grid of holes around it going to a ground plane.  Then make a small shield to go over it and insert it into some of the holes and solder it in.  

The shield cover does what you think - it isolates the chip from radiating junk.  The grid of holes around the pwr supply acts like a shield built into the board itself - it keeps the junk from radiating through the board material.  

Never tried it - but one day...

[col]

I finished the build last night ans the ICL7660SCPA does work like the MAX1044 if you connect pin 1 to the +9v supply. Thanks a lot for the help while I've been trying to get this sorted,

Col