using the +18V and -9v configuration of a Klon Centaur creates Annoying frequenc

[Yoshi]

Hello. I incounter myself with a big problem. Im trying to use a voltage elevator like the Klon Centaur in a JRC4558 that is in a Ts-808 (protoboard)
The problem is that using this configuration creates a very High frecuency thats pears the ears. I think is like 9 or 10k but it really hurts

Is there a way to prevent that high frecuency?

I left the settings in the picture
thanks

[idy]

Is your chip a 7660SCPA?

If so, do you have pins 1 and 8 jumpered? (schematic does not show pin 1, this implies you are using the 7660A.)

The SCPA version is "super" in that connecting 1 to power (or jumper to 8, power+) doubles the frequency into ultra sonic.

For pedals you pretty much need the SCPA version. Maybe there is also 7660S that is ok.

[bean]

Is your chip a 7660SCPA?

If so, do you have pins 1 and 8 jumpered? (schematic does not show pin 1, this implies you are using the 7660A.)

The SCPA version is "super" in that connecting 1 to power (or jumper to 8, power+) doubles the frequency into ultra sonic.

For pedals you pretty much need the SCPA version. Maybe there is also 7660S that is ok.

Just to piggyback on this comment: In addition you can use the TC1044SCPA or TC7662B as a sub, and both require pins 1 and 8 to be tied together to push the operating frequency out of the audio range. However, the MAX1044CPA is also the equivalent of both of those (no "S") and is another good alternative.

[Rob Strand]

If you have a high frequency device, follow what the others have said,
https://datasheets.maximintegrated.com/en/ds/ICL7660-MAX1044.pdf
https://www.renesas.com/us/en/document/dst/icl7660s-icl7660a-datasheet

If you have a low frequency device then you would be best to change it.

For a low frequency device you can reduce noise by increasing the caps:
- C2 and C5 to 47uF to 100uF
- C1 to maybe to 100uF.
- C4 and C4 47uF to 100uF (optional)

All the caps need to be located close to the IC.

While it helps, it's not great advice since a high gain pedal with a the low frequency switcher will inevitably cause the switcher noise to be audible to some degree.

[Yoshi]

wuoooo thats brillant l..l,!!! thanks for the reply Im learning a lot

Im using the 7660S (you can see it in the picture)... when you say "jumpered" you mean that I need to connect Pin1 with Pin 8?

[idy]

Yes, you jumper pin 1 and 8, connect them.

There are lots of examples out there. MadBean's road rage shows a circuit with a switch that allows you to choose whether your chip needs this or not.

[bean]

You can also use caps with a low ESR (equivalent series resistance) for C3 and C4 (your schematic). It can make the charge pump operation a tiny bit more efficient. FWIW.

[Yoshi]

Wuooooo thats cool!!!

How can I do or use that ESR (equivalent series resistance) for C3 and C4 ?? it sounds interesting

[Yoshi]

You can also use caps with a low ESR (equivalent series resistance) for C3 and C4 (your schematic). It can make the charge pump operation a tiny bit more efficient. FWIW.

broooo thanks!! it works l..l,!!!!! you are the best

[bean]

Wuooooo thats cool!!!

How can I do or use that ESR (equivalent series resistance) for C3 and C4 ?? it sounds interesting

It's just a matter of finding the part with low ESR. IOW, it's a manufacturing spec.

Here's an example - 47uF cap with a practically negligible ESR: https://www.mouser.com/ProductDetail/667-EEU-FR1E470
This is another one, although it's scheduled for obselence. This is the one used in all the VFE pedals (which are typically +/-9v operation): https://www.mouser.com/ProductDetail/Nichicon/UMF1C470MDD?qs=STYa3Y5G4R67hN8%252BYHc2xg%3D%3D

Peter (the VFE guy) clued me into using this spec with charge pumps.