Klons and Diodes

[Drew Hallenbeck]

I only build mine with "Unicorn Farts". (D9E)
Once those run out, I have a pretty good stash of D9K that are pretty close and will still be labeled "Unicorn Farts"! 

[mauman]

This is some great information! 

I've been using my Atlas DCA75 to test the diodes, but I noticed that it's testing at 5mA.  When I see the 0.35 Fv, should I be reading that at 1mA or 5mA?  I have a particular darlington Rangemaster I build (thanks Midwayfair for turning me onto those years ago), so I have only really used my Atlas to measure Germanium transistor leakage.  I believe the software can construct voltage curves if I can get it to run on my Mac.

Yes, the DCA75 will show you the full curve if you can get that USB link working, maybe with a Windows emulator on your Mac?

0.35V on a Ge diode would be closer to 1 mA than 5 mA.  Diode Vf is always relative to a current, and it's not much use without it.  The DCA75 (and DCA55) show you the measuring current (usually 4 to 5 mA.)  I have a Fluke VOM with a diode function, and it measures at 1 mA (I've deduced), so those results don't match the DCA.  I would guess that published Vf measurements not referencing a current would have been made with a VOM, so around 1 mA.

[Aleph Null]

I've got some 1N34A's lying around—my local electronics shop had a whole roll of them, so I bought a handful. They read around 500vF for me. I also have glass bodied 1N60's that measure in the 350–400 range. DM me if you want a couple.

Honestly, though. Any diode with a lower forward voltage will probably work fine. If it were me, I'd through in some 1N518's and up the current limiting resistor to taste just to be a contrarian.

[Timko]

I was able to scrounge up a PC to run the Atlas software on (emulation when you need to use the USB ports is shaky at best on a Mac), and the graphical results are pretty interesting!  I'm finishing the first of the 3 pedal etching this evening so I can build my own personal test pedal, and look forward to first giving these diodes the ear test then the graph test.   

One thing is for certain - while both the 1N270 and D9E diodes read around 0.35V between 1mA and  1.2mA, the graphs from 0mA to 5mA look very different.

[jwin615]

That difference is what's referred to as the "knee"
Outside of average Vf being lower on Ge diodes, that softer knee is the other major differentiating factor. Some believe that's what contributes to the more "organic" feel with ge diodes. It's more apparent with a circuit that you're just barely clipping, or "edge of breakup" tha it is in a full on distortion setting.
Tie two Ges in series, anode to cathode and take a look
You should get a higher overall Vf, but keep some of the knee characteristic. Handy when using Ges on a switch with Si or LEDs to keep the volume drop from being as drastic with the Ges but still getting that Ge "mojo"

One thing is for certain - while both the 1N270 and D9E diodes read around 0.35V between 1mA and  1.2mA, the graphs from 0mA to 5mA look very different.

[matmosphere]

Was it Midwayfair who did a subjective diode listening test with various diodes in the Klon.  I can't find the page unfortunately.

Yeah, and then people bought out the ones that I said I liked, and claimed that they were the most accurate, even though they demonstrably weren't even remotely accurate to the Fv of a typical germanium diode, in a pedal that most people never use as a distortion. Goddamn I hate every fucking thing about this stupid pedal. There's got to be some way of finding that post on the forum, unless I removed it out of spite.

Knowing the Fv of a diode is completely useless unless you know you're using the the same meter as the person who measured it. Just socket the diodes and use your ears for the ones you like. Screw accuracy.

Of all the things I have read about the Klon this is my favorite!

[lars]

I only build mine with "Unicorn Farts".

https://61brewthru.com/wp-content/uploads/2022/05/Duclaw-Unicorn-Farts.jpg
Might make for some interesting builds, especially depending on how many Unicorn Farts you "use".

[GrindCustoms]

Yeah but which ones have Unicorn Tears?


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You just made my day, thank you! 

[jimilee]

Yeah but which ones have Unicorn Tears?


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You just made my day, thank you! 

Always, unicorn years forever.


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[Timko]

After a few weeks of different diode testing, I realize that my ear is not that sophisticated .  I did like 3 variants of D9Es I have.  I also liked some D18s and some D9Gs.  I had some 1n34a's from various sources - some sounded good, some sounded meh.  After some testing, I did find that I tended to like diodes with a lower forward voltage.  I combined that with a few of the "Silver Pony" tweaks (more clean in the clean path, better balance on the gain knob) and a decrease in the R2 value from 2k to 680e made for a perfect sounding pedal for my guitars (vintage spec'd single coils or filtertrons) along with my fingerstyle were a perfect match.

Conclusion:  There is no such thing as a single magic part (well, I'm on team germanium transistor for treble boosters, but that's another fight for another day).  Parts are part of a system, and changing one affects how others respond.  That, combined with both the gear you're playing and the way you play are going to have more of an effect on your sound than some unobtainium part.

You can check out the build report section for my completed builds!  The 24mm pots in this thing look awesome .

[peAk]

but....but....but......what does the NOTAKLÖN use?