Bare Bones (single rail) Klon project question

[mordechai]

Hi...I found the "bare bones" (no charge pump) Klon-type project out on a different website, and want to try building it up.  It's my understanding that the 12V zener diode in the original circuit was selected for use with the charge pump that bumps up the voltage...but since the "bare bones" project gets rid of the charge pump, do I need this zener diode in the power section?  Would there be a problem with powering the circuit if I use it?  Should I use a different one (a 9.1V diode) or none at all?

[banjerpickin]

Can you post the schematic so we can see what was cut out and where that diode now sits in the power supply?  I'm familiar with the Klon charge pump and may be able to help, just never heard of that particular layout.  If you're talking about D4 (or Z1) it should probably stay in there to protect the V+ (+9v) part of the circuit from polarity inversion:

http://www.coda-effects.com/2015/09/klon-centaur-clone-and-mods-aion.html

I read somewhere you should use a 1N4739 (9.1V) if you swapped the charge pump IC to a MAX1044 to keep the voltage below the MAX1044's max voltage, if that helps.  I'm prepared to be corrected by the much better electrical engineers than myself in this forum, but it seems like you should be able to use either diode, strictly from a voltage standpoint, unless the TC1044 and 1N4742 are married in a way I don't see.

[mordechai]

Sure...I found this on the "other" forum so I hope it's okay to post the pic here.  I seem to remember someone saying, in some discussion thread on this or another site, that the simplified version should use a 1N4739 rather than the 4742, but I may be wrong about that.  Anyway I'd appreciate your thoughts.

[banjerpickin]

Sure...I found this on the "other" forum so I hope it's okay to post the pic here.  I seem to remember someone saying, in some discussion thread on this or another site, that the simplified version should use a 1N4739 rather than the 4742, but I may be wrong about that.  Anyway I'd appreciate your thoughts.

Sorry I went back and edited my reply after I thought some more, might want to take a look.  Are you referring to D4 on the schematic?  It looks like they removed the entire charge pump as a module, so IC ESD protection isn't an issue - I believe that was the original and primary purpose of D4/Z1. I just don't see how leaving the 1N4742 in, or changing it to a 1N4739, could possibly hurt anything.  You probably should include one or the other to protect against polarity inversion, just in case you plug up a center positive supply.

[slacker]

banjerpickin is right in the original circuit the zener is to protect the charge pump from over voltage in case you plug in an unregulated power supply or try to run it off 18 Volts or something. It will only protect it for a short while though if you leave too high a voltage connected for too long the zener could die and the protection is gone. You don't need it for the bare bones version, you could leave it in and it will provide some reverse polarity protection, like the normal reverse bias diode protection it can die if the voltage is reversed for too long. I would remove it and replace it with what ever reverse polarity protection you normally use.

[mordechai]

I usually use 1N4001 in my fuzz and simple overdrive builds...would that do the trick?

[slacker]

Yeah

[banjerpickin]

Glad I was (somewhat) of assistance!