The dreaded diode debate

[eh là bas ma]

I'm not a wine connoisseur, more of a wine kind-a-sewer ... I can't tell if the grapes that year were frostbitten, or what year, but I know when I taste wine whether I like it or it tastes more like vinegar...

I think there are two keys to unlock the cage of ignorance :

- Having the right words : signifier and signified, in linguistic science. We have to be able to name something before we get the concept accurately. For exemple in a forest, all i can see is trees and plants. If I knew the name of every and each things, I would be able to see a lot more.

- Paying attention : We have to be able to focus on something, more than 30 seconds.

I started to appreciate wine only after i heard many winemakers talk about it, while we were drinking it.

 

[Feral Feline]

I can do the wine thing far better than I do the diode thing... but I sincerely appreciate your well considered response. as always sir surly cat...

Well, sincerely, seriously I certainly didn't meme to be surly...

 

[jesuscrisp]

What am I missing?

Your ears it seems.

Seriously though, I personally think diode switches, especially elaborate rotaries like in the Palisades, are sort of overrated when it comes to making a pedal more versatile. Even more so because depending on the circuit it can really throw off the volume balance and lead to unintentional clipping after the clipping stage, which may or may not sound cool (and usually it doesn't).

Nevertheless, there certainly is a difference, but it's one you have to figure out yourself. I can't tell you what to hear and listen for. Just because I describe LEDs as more crunchy with a crackly note decay, silicon as sharp yet smooth and germanium as runder, warmer but fizzier, you won't hear it if you're not hearing it already. Or asymmetrical clipping giving you more clean bleed through than symmetrical.

Both for soft and hard clipping it's also about how much op amp clipping and compression you get before the diodes start clipping the signal. Yes you can get similar tones with nay configuration of diodes, but the clipping character and feel will be different at similar gain and volume levels.

 

[MichaelW]

I've got three electric guitars, two with P-90s, and one with humbuckers, so not a lot of options.

Well, the OBVIOUS problem here is that you don't have enough guitars.....I'd recommend (for the sake of science) a couple F styles. Tele (or 2 or 3) Strat, and a Jazzmaster....

 

[Locrian99]

I’d recommend breadboarding a distortion + and put a switch on it for changing the diodes. Just two types would work. A simpler circuit may high light the differences more for you. It’s also a fun circuit to try different mods with.

 

[Laundryroom David]

I’d recommend breadboarding a distortion + and put a switch on it for changing the diodes. Just two types would work. A simpler circuit may high light the differences more for you. It’s also a fun circuit to try different mods with.

This is a great idea.

Fwiw I hear a bigger difference between sym and asym clipping arrangements than I do differences between e.g. 1n34a and bat41 in a klone. That said, different 1n34a or other Ge diodes may give you something a little different. Leakage ya know.

But at higher volume, in a mix … yeah maybe not so much difference to be heard.

 

[jhaneyzz]

I’d recommend breadboarding a distortion + and put a switch on it for changing the diodes. Just two types would work. A simpler circuit may high light the differences more for you. It’s also a fun circuit to try different mods with.

That's a great suggestion...

I just printed out a schematic and I'll definitely do that.

 

[iamjackslackof]

My guess here (and it's simply a guess) is ear training. I'm not sure I hear a ton of difference with diodes either, but I've never spent much time comparing them directly. I can hear (often times) a Strat vs Les Paul in a song, because I've spent time trying to do that. I remember when I first heard people say things like "oh that sounds like an LP through a Marshall" I thought they were full of shit. Now I know you can *learn* to hear subtle differences like that, through ear training/effort. Same with picking out a major 7th vs minor 7th vs dominant 7th chord. Lots of people can, I can tell they all sound slightly different, but I can't hear one and say, yep it's definitely an X chord. But I'm working on that. You get there through ear training. Major vs minor, easy, and most people can do that pretty automatically with no training.
I bet you anything people like Wampler, Keeley, people here who have spent lots more time than I have comparing EQ curves and diodes and listening for subtle changes, can actually hear those subtle changes. But not because they have good ears or it comes naturally (with probably a few rare exceptions). Age and hearing damage can play a part as well, especially if the changes are most present in a frequency range you can't hear well anymore.

TLDR: Ear training.

 

[mdc]

You will never in one thousand years, all things being equal, hear any noticeable difference between two sets of diodes in any real world playing situation. I sincerely doubt anyone here would be able to consistently identify differences in diodes in a blind test once things were normalized for equal loudness.

Find a Vf that works for your use case (ie, gives you the combination of headroom and output volume that you need) and never think about them again.

 

[mdc]

Your ears it seems.

The OP was polite enough to ignore this, but I'm just going to point out how needlessly rude and unhelpful this was.

 

[Locrian99]

My guess here (and it's simply a guess) is ear training. I'm not sure I hear a ton of difference with diodes either, but I've never spent much time comparing them directly. I can hear (often times) a Strat vs Les Paul in a song, because I've spent time trying to do that. I remember when I first heard people say things like "oh that sounds like an LP through a Marshall" I thought they were full of shit. Now I know you can *learn* to hear subtle differences like that, through ear training/effort. Same with picking out a major 7th vs minor 7th vs dominant 7th chord. Lots of people can, I can tell they all sound slightly different, but I can't hear one and say, yep it's definitely an X chord. But I'm working on that. You get there through ear training. Major vs minor, easy, and most people can do that pretty automatically with no training.
I bet you anything people like Wampler, Keeley, people here who have spent lots more time than I have comparing EQ curves and diodes and listening for subtle changes, can actually hear those subtle changes. But not because they have good ears or it comes naturally (with probably a few rare exceptions). Age and hearing damage can play a part as well, especially if the changes are most present in a frequency range you can't hear well anymore.

TLDR: Ear training.

I agree with this completely. Which is one of the reasons I recommended the distortion +. One of my first builds I built an ocd on a 1.4 board I put the germ diode on a switch. After doing so and playing with the pedal I struggled to hear a difference with the 34a in or the 34a out. At one point I breadboarded the distortion + to play around with different diodes and other mods. And could clearly hear the difference between diode types in that circuit, revisit the ocd pedal recently and I could hear the difference now with the switch much more than I originally could. I think because my ears/brain had a better idea of what to look for.

In the end though @mdc is probably right no one will be able to hear it. But a lot of the subtle things we go for in chasing tone is more for us as the player as well. A slightly different tone can inspire us to really dig in, back off or have a new idea. I can think of multiple occasions where a particular sound helped me find “groove” if you will and I felt I played better because of it.

 

[traumprinz]

The best way to compare diodes is probably to have some sort of volume compensation after them to normalize levels. The volume drop when switching from silicon to germanium or LED to silicon/germanium is drastic enough that it's hard to objectively compare otherwise IMO. Comparing Schottky diodes to germaniums might give you a clearer picture since their Vfwds are similar but their knee is different.

Contrary to an earlier post, I'd argue that the soft knee of germanium is what is most desirable about using germanium diodes (at least in theory), not the low Vfwd. Otherwise you could use Schottky diodes anywhere a germanium is called for. The soft knee should result in softer clipping vs. harder clipping for silicon (and other types with a less soft knee), although germanium also starts clipping earlier than typical silicon diodes.

The Vfwd plays a role too, but it has more impact on headroom and potentially output volume if there is no gain recovery stage after the clipping stage (e.g. Univox Square Wave Fuzz, Electra Distortion).

I think the difference is fairly subtle and often overstated, and that you aren't going to find any kind of sound revelation by swapping diode types in a circuit, but I also disagree with this:

"You will never in one thousand years, all things being equal, hear any noticeable difference between two sets of diodes in any real world playing situation."

 

[manfesto]

Otherwise you could use Schottky diodes anywhere a germanium is called for.

You can, and lots of people do; A Klone with BAT41s still sounds more like a Klone than any other circuit, the coring circuit of the Promethium and the octave stage of the Parentheses work as-good-or-better when you sub in more consistent schottkys, etc.

For as long as people have been asking “what can I sub for a 1N34a in this circuit”, people have been suggesting “just use a BAT41” without much ado.

And it basically always works, because they’re diodes with similar forward voltage.

Is the softer knee of germanium measurable, probably even recognizable in a back-to-back ABX listening test against a BAT41? Sure.

Is it worth the price and effort? That’s a value judgment down to the individual builder and/or user (many of whom hear with their eyes and not their ears, let’s be real).

 

[jhaneyzz]

I really appreciate the points you all are making.

Kind of like eh lá bas ma was saying earlier, you're giving me the vocabulary to put words to what I am hearing allows me to realize i'm hearing them in first place.

I realize, after reading several posts above, that I have definitely recognized things you mentioned.

This will really help as I tweak my builds.

 

[szukalski]

It could also be how you're using your pedals. Maybe you're not getting enough juice through to clip the diodes?

Some circuits are pretty ignorant of diode type, others more so. I find the odd circuit here and there where removing the diodes doesn't change tone at all!

I just found this video the other day which was pretty informative:

 

[jhaneyzz]

It could also be how you're using your pedals. Maybe you're not getting enough juice through to clip the diodes?

Some circuits are pretty ignorant of diode type, others more so. I find the odd circuit here and there where removing the diodes doesn't change tone at all!

I just found this video the other day which was pretty informative:

I just rewatched this with what I've learned recently

very interesting. and I see what you mean about the need for juice.

 

[Alan W]

I've got three electric guitars, two with P-90s, and one with humbuckers, so not a lot of options.

I don’t want to be pushy, but from my sense of what drives you, — you should get a single coil guitar, just to grok all these interactions better. I’m not saying you’ll decide you want to mainly play single coils, but as a student of gain circuits, etc., it can be pretty demonstrative to see what happens when you hit things with a slightly different signal.

P-90s may be my favorite PU type, and I rarely play a humbucker that wows me (last time was a Throwback, unusually (to me) open and dynamic sounding for a humbucker). I just finished two years of mainly playing a Strat and a Tele, both straight single coil equipped, and I’m enjoying playing on some older guitars right now, that are not Fendery. It’s meant having to re-assess much of my signal chain, which I had changed pretty much during those 2 years.

 

[jhaneyzz]

I don’t want to be pushy, but from my sense of what drives you, — you should get a single coil guitar, just to grok all these interactions better. I’m not saying you’ll decide you want to mainly play single coils, but as a student of gain circuits, etc., it can be pretty demonstrative to see what happens when you hit things with a slightly different signal.

P-90s may be my favorite PU type, and I rarely play a humbucker that wows me (last time was a Throwback, unusually (to me) open and dynamic sounding for a humbucker). I just finished two years of mainly playing a Strat and a Tele, both straight single coil equipped, and I’m enjoying playing on some older guitars right now, that are not Fendery. It’s meant having to re-assess much of my signal chain, which I had changed pretty much during those 2 years.

I've definitely got the Tele itch. but I gotta sell some stuff. I've got the list made, just need to clean, photograph and post.

Then find the perfect tele....

 

[jhaneyzz]

It's interesting, after reading all these posts, watching that video and playing with the circuit emulator it mentions I went and played a few pedal's I've got with switchable diodes and yeah.... i couldn't pick it out in a song, but i think I'll be able to put words to the differences before long.

 

[Locrian99]

It is pretty crazy the difference a guitar will make. I almost feel like I need a different od/dirt pedal board for my strat vs lp.