Substituting an ICL7660 for an ICL7660S/TC1044S in the Kingslayer: OK or no?

[solderfumes]

I've been corralling the parts to put together a Kingslayer.  My local go-to electronics shop only had the ICL7660 charge pump in stock, and I foolishly bought it before I knew the difference between it and the TC1044S/ICL7660S/MAX1044.  I've heard people warning that there will be a whining noise due to the 7660's oscillator frequency being within the audible spectrum.  Will I be able to get around this by adding an appropriate (say, 100uF, 25v) filtering capacitor across the -9v and +9v rails, or is the noise coming from somewhere other than the voltage ripple?

[solderfumes]

I've now read this: http://geofex.com/circuits/+9_to_-9.htm

Am I correct in hoping that the Kingslayer will be OK because signal ground is ground while power ground is the -9v rail?  If not, can someone detail what are the special precautions one would take to correct the problem?  I can of course go find another charge pump online, but now I'm curious.

[jkokura]

No. If you use a 7660cpa instead of a 7660scpa you will experience whining/high pitch frequency noise. Adding another filter cap will not stop it.

You can try your pump out, but if it whines you'll need to aquire an scpa version.

Jacob

[solderfumes]

Oh I'm a dummy... I think the special wiring one would have to do is exactly the transistor trick detailed right underneath in that article.  Can someone confirm this?  I can't parse whether that's just one trick that might help or if it's the special wiring he's describing.

[jkokura]

Yeah, that article from RG has nothing to do with the issue at hand really.

Jacob

[solderfumes]

OK.  So what exactly causes the whining?  Where is the noise getting into the signal path?

[RobA]

OK.  So what exactly causes the whining?  Where is the noise getting into the signal path?

Everywhere. It's on the power rails and in the ground itself. You aren't going to clean it up with a cap or a bunch of caps or even caps and inductors and ... The best solution is to go with a charge pump that has a clock that's sure to be well above the audio band. Personally, I just stick with the LT1054 or the TC7660H. If you use the LT1054, you have to make sure that pin 1 isn't connected, but other than that it is a really good part to use.