madbeanpedals::forum

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?

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.)

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  ;D . 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.

Yeah but which ones have Unicorn Tears?


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Quote from: jimilee on November 19, 2023, 08:37:02 PM
Yeah but which ones have Unicorn Tears?

The ones from AliExpress, obvs

Quote from: jessenator on November 19, 2023, 08:51:33 PM

Quote from: jimilee on November 19, 2023, 08:37:02 PM
Yeah but which ones have Unicorn Tears?

The ones from AliExpress, obvs

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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&

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

Quote from: Willybomb on November 19, 2023, 09:44:45 PM
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.

Quote from: midwayfair on November 19, 2023, 10:41:47 PM
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.

Quote from: lars on November 19, 2023, 11:28:33 PM

Quote from: midwayfair on November 19, 2023, 10:41:47 PM
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

Quote from: Hefty on November 20, 2023, 12:23:24 AM

Quote from: lars on November 19, 2023, 11:28:33 PM

Quote from: midwayfair on November 19, 2023, 10:41:47 PM
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.

Quote from: jimilee on November 19, 2023, 08:37:02 PM
Yeah but which ones have Unicorn Tears?

The ones with the goop.


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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. 

Quote from: midwayfair on November 19, 2023, 10:41:47 PM

Quote from: Willybomb on November 19, 2023, 09:44:45 PM
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.

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"!  ;)

Quote from: Timko on November 21, 2023, 03:26:10 AM
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.

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.

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.

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"

Quote from: Timko on November 22, 2023, 03:20:21 AM
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.

Quote from: midwayfair on November 19, 2023, 10:41:47 PM

Quote from: Willybomb on November 19, 2023, 09:44:45 PM
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!

Quote from: Drew Hallenbeck on November 21, 2023, 03:07:36 PM
I only build mine with "Unicorn Farts".

https://61brewthru.com/wp-content/uploads/2022/05/Duclaw-Unicorn-Farts.jpg (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".

Quote from: jimilee on November 19, 2023, 08:37:02 PM
Yeah but which ones have Unicorn Tears?


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You just made my day, thank you!  ;D

Quote from: GrindCustoms on November 25, 2023, 12:12:56 PM

Quote from: jimilee on November 19, 2023, 08:37:02 PM
Yeah but which ones have Unicorn Tears?


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You just made my day, thank you!  ;D

Always, unicorn years forever.


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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 :).

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

:)