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I have a board that calls for a 1N4739 Zener diode, which I thought I had. However, upon close inspection the diode I have is actually a 1N4733 diode instead of a 1N4739 called for in the circuit. I know the Zener voltages are actually different for the diodes, 5.1V for the 4733 compared to 9.1V for the 4739. Would it be possible to substitute the 4733 for the 4739 in the circuit (Photon Phuzz) with no real change in the fuzz? Or does the Zener voltage make a real difference in this circuit?
I just received a large order of parts for different projects and had I known that I had the wrong diode, I would have ordered the correct one. It seems overkill to order one diode so that the build is to spec, but I will do it if I have to, just in the future when I have the need to order other parts.
Thinking about what a Zener diode does, it will ‘clamp’ the signal to value of the Zener. So while the Photon Phuzz uses a +9v supply and 9.1v zener, that Zener will not impede the entire signal voltage swing. Still, any diode in that position on the schematic is going execute some heavy asymmetric clipping. However, a 5.1v Zener will certainly limit the signal voltage swing significantly. So, while the circuit will still work (somewhat) with the 5.1v Zener, it will certainly sound different with the 9.1v Zener. I recommend procuring the correct Zener for this project to get out it all that it was designed to deliver.
That is what I thought. I know Zener diodes can be used for voltage regulation so I figured that voltage through the circuit would be heavily affected using the one I have, especially since the Zener voltage of the diode I have is about half of the one called for in the circuit.
hey now,
photon here. it totally doesn’t matter. you can use any diode you want to there. the ONLY reason i chose the 4739 for this circuit in the first place was it was literally the first diode i pulled out of my diode drawer.
you can use anything as a sub. it may sound slightly different, but think about it… its being run as a 9.1v diode. you’re using a 9v supply. so odds are, you’re never even hitting the breakdown voltage of the zener.
i’ve built these with 1n34a and 1n60 germaniums, i’ve used 4148, i’ve used 4001’s, very little difference really that i recall. so i’d suggest socket the sucker, and try what you have in stock. you may find that even an led will sound ok. it’s designed to be a VERY forgiving circuit. there’s really no absolutes, and you have easily a 20% tolerance on all parts.
plug in what ya have, and try it. odds are it will work fine.
when i first built this, and the many i built after in the stupid simple overdrive series this came from, i totally wasn’t thinking about much of anything. it was literally the first crap i pulled from my junk drawer. it sounded great, so i drew the circuit. there’s no magic, there’s no mojo, there’s no need to stress.
one of the first rules of most jimi photon circuits is work with what you got. in this case, a 5.1v zener should make zero difference. if you’re concerned about it, use two of the 5.1v zeners you have in series, should be more than close enough at 10.2v <zeners are additive like that> for it to be fine.
seriously. just build the sucker.
if it really seems to be an issue, sub what ya got, order the proper part. but me?i totally would not worry about it.
hope that helps ya bud
peace
PjP
btw… the original incarnation HAD NO DIODE AT ALL. just an fyi
PjP
Jimi – Thank you for the detailed explanation. I suspected that only the Fvd of ANY Zener would take effect on the signal. But not having yet built one your Photon Phuzz circuits, I was unsure if a 5.1v Zener would exact its breakdown value against the audio signal. I love it when I learn something new – whether from building or the builder.
Absolutely great to hear from the board designer himself! I will definitely socket the diode and see! I’ve got a lot of them – 4148’s, 4001’s, 1N34’s, 1N914’s, D9’s, 1N4733’s and the 4739’s are on the way.
all good, guys! have fun, make loud fuzzy noises!
peace!
PjP
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