Klons and Diodes

[Timko]

Hi all! After spending the past spring and summer focusing on other things (I was 1/2 of the team running Disc Golf Pro Tour in Kansas City for those who are in the disc golf scene), I'm coming back to the pedal world this fall and winter!  I finally finished up a couple of projects on my bench and began taking on a few new things.  A friend of mine asked me to build him a Klon.  Now I've built a few at various points in my pedal building career but never really gravitated towards them.  I've been more of a clean/treble boost guy, so much of my research has focused there.  But since I'm building him one, I wanted to get a deeper understanding of the circuit and the topology.

So this is a question about Klon diodes, a question that's probably older than time.  I've done a bit of reading already, and saw 2 things mentioned that are directing me in my builds:
* The diodes should have a forward voltage of 0.35v
* Keith at BYOC found that D9E diodes are a very, very close match sonically

I bring these two points up because I bought a collection of Russian diodes off of eBay a few years ago which contains both #1 and #2 above, but I found out that the D9Es (along with the other D9's series I have) measure in the 0.5v, not in the 0.35v.  I'm going to socket my personal build to to see what I prefer sound wise.  And I tend to believe more in values and math, and will gravitate toward finding a diode in the voltage range rather than one that someone says is close in their opinion sound wise.  But from those on this forum who have done a number of Klon builds, what has been your experience here?  Have you found that as long as the forward voltage is in that 0.35v, you're getting the sound you're expecting?

[mauman]

Kinda.  Remember that a diode's forward voltage is a curve that varies with the current, so you'll get a different Vf result if you measure with different currents.  I have some D9E diodes, and they consistently measure 0.3V at 1 mA, and 0.49V at 4.5 mA.

Some Russian Ge diodes with similar curves include D9J, D9B and D9V.  The readily available silicon BAT42 Schottky diode measures 0.27V @ 1 mA, but only 0.32V @ 4.5 mA, so it's similar but not quite the same.  Maybe close enough, though, you could do an A/B sound check for any audible differences. 

(PS: Ge diodes (and transistors) change characteristics pretty radically with temperature.  So in addition to using a consistent current, you also need to measure at a consistent room temperature, and not warm them up with your hands for example.)

[jessenator]

Echoing what mauman said, there are a number in the range you could try, rare and common, expensive anr affordable. I'll definitely agree that the soviet era ones are excellent replacements in other circuits requiring Ge clipping diodes, too (super-fuzz in particular), as well as being slightly more affordable than NOS American fare.

As far as tonal qualities… you'll get differing opinions, as well as differing opinions on whether or not there needs to be a difference if opinion   

If you want my most neutral of 2¢, I'd say experiment to see/hear what you want out of it, but I know that cost can be a factor. Heck, I couldn't decide so I made a board with switch-selectable pairs. You could go totally unorthodox and try silicon diodes, LEDs, or even two-legging certain transistors. Although I'll admit my own bias was "screw the mojo" and find something I liked the sound of with this circuit, so take that with some grains of salt.

I found this article/page to be a nice inspiration: https://www.guitarpedalx.com/news/news/a-brief-hobbyist-primer-on-clipping-diodes

If you want my subjective 2¢, help yourself to a whole salt lick  . I found these to be my favorites/ranking:
1N270
1N60P
BAT43
D9E
1N5817 (noticeably quieter)

Hot take: i found the three versions of 1N34A I had to be too farty/dull and I personally don't recommend them at all.

[jimilee]

Yeah but which ones have Unicorn Tears?


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[jessenator]

Yeah but which ones have Unicorn Tears?

The ones from AliExpress, obvs

[jimilee]

Yeah but which ones have Unicorn Tears?

The ones from AliExpress, obvs

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[mauman]

If you want to see a large number of Ge diode curves, including the ones discussed here, try https://www.freestompboxes.org/viewtopic.php?t=32837&

[Willybomb]

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

[midwayfair]

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.

[lars]

Just socket the diodes and use your ears for the ones you like. Screw accuracy.

This. Sometimes you find oddball components with no markings, you put them in a circuit, and the clouds part with a ray of beautiful noise.

[Hefty]

Just socket the diodes and use your ears for the ones you like. Screw accuracy.

This. Sometimes you find oddball components with no markings, you put them in a circuit, and the clouds part with a ray of beautiful noise.

I agree and clouds part differently for every ones ears

[midwayfair]

Just socket the diodes and use your ears for the ones you like. Screw accuracy.

This. Sometimes you find oddball components with no markings, you put them in a circuit, and the clouds part with a ray of beautiful noise.

I agree and clouds part differently for every ones ears

It's mostly steam that escapes when my ears part.

[Doorlord]

Yeah but which ones have Unicorn Tears?

The ones with the goop.


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[Timko]

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. 

[playpunk]

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.

I think you're an influencer, by any definition. Get ready for your photoshoot.