The dreaded diode debate

[eh là bas ma]

So far we mentionned Led, ge diodes, silicon, bat41, etc.

But there is still a good number of combinations that can give great and singular results. Like bat41 in series wit 1N4148, or ge diode in series with 1N4001 or Mosfet + led, etc.

I found out about these combos, mostly in build docs, where the vintage diodes were no longer in production. The person who wrote the build docs often suggests some combo to adjust the Vf, in order to emulate some rare diodes. I spent some time exploring these combos and it's very interesting.

Of course it depends on the circuit characteristics, that's what makes it so hard sometimes. Looking for a needle in a haystack sort of thing.

Palisades build is really good to experiment because the overdrive is a classic, and you can use the volume boost to adjust, depending on the clipping. But it's not necessary the best circuit for a lot of diodes settings. I had good results with a DS-1, to be able to appreciate some combinations.

You can find a lot of great ideas, useful in many circuits, here :

https://www.diystompboxes.com/DIYFiles/up/Build_Your_Own_DS-1_Distortion.pdf

I really like p.20 and 21 : a diodes blend pot !

I wonder if you can tell the differences between op-amps ? Can you hear TL72 doesn't do what 4558 does ?

 

[Feral Feline]

I wonder if you can tell the differences between op-amps ? Can you hear TL72 doesn't do what 4558 does ?

Visual Sound... what a name for a company!

 

[jhaneyzz]

Visual Sound... what a name for a company!

I see why he is shielded behind bulletproof glass... fanatics cannot be trusted...

FF... you are a class act...

 

[Locrian99]

This was somewhat interesting.

Busting the myth of magical op-amps and diodes...? | Everyone knows the the mystical 4558 op-amp IC chip is responsible for the best overdrive tones, right? I mean, even Stevie Ray insisted on it in his... | By Wampler Pedals | Facebook

26K views, 416 likes, 17 loves, 93 comments, 119 shares, Facebook Watch Videos from Wampler Pedals: Everyone knows the the mystical 4558 op-amp IC chip is responsible for the best overdrive tones,...

fb.watch

Unfortunately it’s a Facebook video thing.

Wampler doing several op amp and diode comparisons.

 

[eh là bas ma]

This video above (reply #42) compares only different 4558 chips, so I wouldn't expect a real difference, it can only be some "subtle slight difference". I do think that in some cases, along with other adjustments, it can take part in a more noticeable change of tone.

If he had tried other chips, like TL72, TL82, NE5532, OPA2134, LM358, etc... the changes would have been much more noticeable.

I am still ignorant in electronics, but i often read that the op-amp can't work alone, the sound's characteristics are shaped by the op-amp and the components associated to it.

The speaker says a lot "they sound basically the same". About TI4558 and JRC4558, he mentions a "subtle slight difference", like it's insignificant.

In both cases, I think he's missing the point. It's a question of little details if you want to get the best possible sounds from a circuit. "basically the same" isn't a valid expression from that perspective. You can't think like that, or you'll miss the details. Like eating a piece of cake with a big construction machine instead of a little spoon.

The same rule applies in every fields of activity in life, once you reach a point where it gets more and more difficult to improve yourself. Like playing guitar, for exemple.

At some point, these little details are adding up and start to make a real difference. That's how you level up from very good to excellent, I think : many little details that wouldn't change the game alone, but all together it gets amazing.

That's why whatever the size of the improvement you are making, it should always be a cause for joy and fullfilment ?

 

[owlexifry]

I've heard for a lot of very authoritative sources that at low gain, the diodes are not even in the signal.

for hard clipping diodes that simply clip to ground (eg DOD250) - this is absolutely true.

but for soft clipper diode pairs in an opamp NFB scenario, even at low gain, the diodes are still doing a job.
take them out and the sound changes dramatically.

what may be a significant difference to others' ears may not be to yours, for all sorts of reasons mentioned above.

 

[jhaneyzz]

This video above compares only different 4558 chips, so I wouldn't expect a real difference, it can only be some "subtle slight difference". I do think that in some cases, along with other adjustments, it can take part in a more noticeable change of tone.

If he had tried other chips, like TL72, TL82, NE5532, OPA2134, LM358, etc... the changes would have been much more noticeable.

I am still ignorant in electronics, but i often read that the op-amp can't work alone, the sound's characteristics are shaped by the op-amp and the components associated to it.

The speaker says a lot "they sound basically the same". About TI4558 and JRC4558, he mentions a "subtle slight difference", like it's insignificant.

In both cases, I think he's missing the point. It's a question of little details if you want to get the best possible sounds from a circuit. "basically the same" isn't a valid expression from that perspective. You can't think like that, or you'll miss the details.

The same rule applies in every fields of activity in life, once you reach a point where it gets more and more difficult to improve yourself. Like playing guitar, for exemple.

At some point, these little details are adding up and start to make a real difference. That's how you level up from very good to excellent, I think : many little details that wouldn't change the game alone, but all together it gets amazing.

That's why whatever the size of the improvement you are making, it should always be a cause for joy and fullfilment ?

I definitely don't subscribe to the "it just doesn't matter" camp. but I'm neither a musician first, nor an electrical engineer first. I am trying to train my ear, but I want to concentrate on the things that matter, not the things that barely matter.

 

[jhaneyzz]

This video above compares only different 4558 chips, so I wouldn't expect a real difference, it can only be some "subtle slight difference". I do think that in some cases, along with other adjustments, it can take part in a more noticeable change of tone.

If he had tried other chips, like TL72, TL82, NE5532, OPA2134, LM358, etc... the changes would have been much more noticeable.

I am still ignorant in electronics, but i often read that the op-amp can't work alone, the sound's characteristics are shaped by the op-amp and the components associated to it.

The speaker says a lot "they sound basically the same". About TI4558 and JRC4558, he mentions a "subtle slight difference", like it's insignificant.

In both cases, I think he's missing the point. It's a question of little details if you want to get the best possible sounds from a circuit. "basically the same" isn't a valid expression from that perspective. You can't think like that, or you'll miss the details. Like eating a piece of cake with a big construction machine instead of a little spoon.

The same rule applies in every fields of activity in life, once you reach a point where it gets more and more difficult to improve yourself. Like playing guitar, for exemple.

At some point, these little details are adding up and start to make a real difference. That's how you level up from very good to excellent, I think : many little details that wouldn't change the game alone, but all together it gets amazing.

That's why whatever the size of the improvement you are making, it should always be a cause for joy and fullfilment ?

Not true my friend..... he had a video IC as well and it was perceived as barely noticeable difference.

 

[eh là bas ma]

Not true my friend..... he had a video IC as well and it was perceived as barely noticeable difference.

That was a cheap trick. What's next ? He will pull a rabbit out of his hat, or some fudgecicle, put it in the TS808, and the public will say "it's barely noticeable" too ?

 

[jhaneyzz]

You spelled Fudgicle incorrectly... bitch..

 

[jhaneyzz]

 

[Feral Feline]

I like fudgesicles.

Some people are colour-blind, some are bilaterally challenged, some bat both ways, a few have perfect pitch... I'm just saying that we're all wired differently.

I've got zero math acumen, so it still amazes me when a store-clerk can't count back change to me properly or I totally confuse them by making up the difference in change so I can get a fiver back instead of $4.72 — (geeeeeze. doesn't anybody still prefer cold hard cash?).

So some people are great at hearing things, like my guitar friend with golden ears — I can't hear things he can; more so, the singer in his old band has phenomenal ears and can hear nuances across the treble range that guitar-buddy cannot!
I asked guitar-buddy about his ears and he said he'd been working on it since we were teens, that it wasn't intuitive and obviously didn't happen overnight.

Differences in diodes, as mentioned may come down to practice, ie ear-training. Spending time and learning, listening and trying to hear what others could only vaguely describe... "Sounds really warm, it has the brown sound." WTFudgesicle do those words even mean exactly, especially if we aren't all wired the same way? It doesn't matter — for some, for others it does.


Let me part this post with a couple thoughts:

1) Two things that are mostly metal, have four wheels, some paint, and seat two people — one's a dump-truck the other's a Ferrari.

2) Flour, water, Yeast & Salt — the basic ingredients used to make bagels and croissants, and so much more.

Sometimes I want a bagel, other times a croissant.​

What the hell do those two thoughts have to do with diodes?

Extrapolate.

 

[eh là bas ma]

I like fudgesicles.

Did you mean "fudgsicles" ?

From my experience, you should probably be more careful with how you spell this word on this forum. We wouldn't want any incident, right ?

 

[jhaneyzz]

Far more sensitive a subject than diodes...

 

[giovanni]

I haven’t spent any time comparing diodes or opamps for that matter, so I may be missing a lot of nuances.

But as an electrical engineer, having studied a lot of these circuits, I believe there are a couple things that are way more important than component selection, in the majority of cases: the circuit design and the eq. For opamp circuits in particular, circuit design is way more important than part selection. There may be circuits tailored to the specific opamp but usually can be adapted to others: no opamp is so “broken” that it can’t be replaced. Opamps are supposed to be ideal amplifiers, so the differences between them consist in how far from ideal they are, that is, how “broken” they are. Maybe very old devices will sound different in a TS but I’m skeptical that newer ones (including the 4558 variants, even compared to TL72) would be audibly different. But again I haven’t spent time doing these comparisons myself so I may be totally wrong. Eq can often compensate for the most obvious differences in opamps, like different bandwidth.

I also always keep in mind that, just like diodes have soft or hard knees etc, all other components in a circuit (including caps and resistors) have non linear behavior. That means they have a tendency to introduce distortion. The book “Small signal audio design” covers this topic extensively and it’s fascinating. There are many ways to minimize the effects of such non linearities, with the most effective one typically being circuit design: things like negative feedback are designed to increase gain and bandwidth and reduce noise (that’s literally EE101) so any such non linearities get mitigated in most opamp based circuit for example (I haven’t seen an opamp circuit that doesn’t use feedback), including non linearities in diodes in the feedback loop. I think this is why forward voltage is so important: circuit design cannot compensate for that. And also why I think we hear any difference as very subtle: the rest of the circuit is working to compensate for these differences! Hard clippers are the exception here since they are not part of the opamp feedback loop so I would expect the differences to be a bit more pronounced there.

Sorry for the way too long post, one final word about fuzzes is warranted since I definitely stepped into that one: fuzz circuits are much simpler than opamp ones and thus component selection (transistors) is much more critical. Transistors are also much simpler devices, far from ideal amps, so each device can be radically different from the next. That’s generally the case, although some fuzzes do use feedback as well, so they can tolerate different transistors.

 

[Cybercow]

OK... stop me if you've heard this one...

I've been building a lot of pedals lately that use germanium diodes.

I've got some of the rarest germanium diodes I've ever seen and they are cool as F@#$. Thanks Nathan...

I've built a Stockade with 8 different diode clipping options...

I've watched every YouTube diode comparison ever recorded.

Except for the volume difference brought on by the change in forward voltage... I can't tell a lick of difference.

I can definitely hear the difference in hard clipping, and I can convince myself that there's a difference in symmetrical and asymmetrical clipping (just barely) but not a difference in the "character" of the one (aside from the volume change)

Please... if I'm wrong, set me straight. but WTF?

IMO, you are spot-on. The extremely subtle nuances of various clipping elements, (not just diodes), are a challenge at best to detect aurally. And while there is a wide range of trace curve transients across the the clipping element spectrum of choice, such trace curve differences are also extremely difficult to detect with the human ear. I'm convinced, by the science of electronics, that all the marketing excitement about various diodes or other clipping elements is just hyperbolic cork sniffin'.

And like many of us who've already crossed this threshold, putting an 8-way switch for clipping element selection into a build is very much like adding a "Diode Decade" circuit. Welcome to the next level.

 

[Big Monk]

As with silicon transistors, which are quite literally all about hFE (anyone talking nonsense about how XYZ silicons have “this tone” or “that tone” are shitbat), silicon diodes are all about Vf.

Same goes for germanium diodes with respect to germanium transistors: Leakage plays a role in the overall effects the Vf or hFE have on the circuit because of the dynamic nature of how temperature affects those parameters.

 

[Joben Magooch]

I have a feeling that a lot of the differences we tend to notice are also influenced pretty significantly simply by KNOWING there's a difference, know what I mean?

When I swap a TL072 in for a 4558 obviously I'm aware of that change being made. And I suspect that alone causes me to "hear" it differently. Same with a lot of diodes and the like.

That's not to say there is no difference whatsoever but I suspect in a blind/double-blind test the differences would be much less noticeable to most. If I gave you an overdrive with a 4558 in it, then took it back and told you I was swapping in a TL072 (but in reality keeping the same 4558 in it as the first place), most would probably claim to hear a big difference between the 4558 and "TL072".

I do also think there is a tendency to equate louder to "better," within reason. You see this a lot in various comparison videos or "shootouts" - if you're comparing two pedals, amps, amp modelers, pickups, etc that sound mostly identical but one has slightly more output - most people will say the louder one sounds "better" and then fill in a variety of buzzwords to back that up accordingly: It's "more articulate, more definition, more clarity, more oomph," and so on. What they really mean is: "it's louder".

So I don't really know where I was going with all that but I guess to say that it seems to me like in many cases the changes or differences or improvements or whatever can often largely be attributed to 1.) knowing "something's different" and 2.) something being louder

 

[Feral Feline]

Right on Joben.

1.) Confirmation bias certainly plays a role in "biasing a circuit".

2.) As you noted about "Louder", I've been very much aware that this factor is probably mostly responsible for my preference for LED clipping.



Now, where did I put my MusicCord Pro cable...? I think it's losing its efficacy 'cause I can no longer hear a difference after more than a decade since they came out — time to replace it with a new one. Argh, they've gone up in price, $499. Well, at least they're still in business. Oh but wait...

Maybe I'll try this one, gotta be just-as-good or better than the MC-PRO as it's HI-FI :

Yeah! The wires are kept separate, no cross intermodulation of ... power ... stuff. Gotta keep it separated, for sure!

"A top-tier cable for the fraction of the cost."
Hmm $220 for the Level 2, but the Level 3 is only a C-note more, $330.
Hmmm.

Jeepers that's a good deal!

The Essential Sound Products MusicCord Pro ES is $999 !
BUT, ESP has wall outlets that'll improve my sound. I'm going to put that in my Band-Rider, all outlets my equipment is plugged into must be converted to ESP outlets...

Only $149, Cryogeniticcally Tweeted and Hoe-spittal graded, what a bargain!


I digress, sorry.

Maybe extract the snake-oil venom and spit out the extrapolation ...

... matching fV diodes, one that's $ilicon and the other that's ₲€₹₥₳₦৲৳₥.

 

[Alan W]

Right on Joben.

1.) Confirmation bias certainly plays a role in "biasing a circuit".

2.) As you noted about "Louder", I've been very much aware that this factor is probably mostly responsible for my preference for LED clipping.



Now, where did I put my MusicCord Pro cable...? I think it's losing its efficacy 'cause I can no longer hear a difference after more than a decade since they came out — time to replace it with a new one. Argh, they've gone up in price, $499. Well, at least they're still in business. Oh but wait...

Maybe I'll try this one, gotta be just-as-good or better than the MC-PRO as it's HI-FI :

Yeah! The wires are kept separate, no cross intermodulation of ... power ... stuff. Gotta keep it separated, for sure!

"A top-tier cable for the fraction of the cost."
Hmm $220 for the Level 2, but the Level 3 is only a C-note more, $330.
Hmmm.

Jeepers that's a good deal!

The Essential Sound Products MusicCord Pro ES is $999 !
BUT, ESP has wall outlets that'll improve my sound. I'm going to put that in my Band-Rider, all outlets my equipment is plugged into must be converted to ESP outlets...

View attachment 44119 Only $149, Cryogeniticcally Tweeted and Hoe-spittal graded, what a bargain!


I digress, sorry.

Maybe extract the snake-oil venom and spit out the extrapolation ...

... matching fV diodes, one that's $ilicon and the other that's ₲€₹₥₳₦৲৳₥.

Well, I was a member of that team for a number of years. The worst part about the entire power cord thing was that it made a positive difference, in double blind tests I took part in. And, even though I drank the cool aid, the notion that 3 feet of wire, after going through the hundreds in my house and the miles from the… would make an audible difference, just never made sense.

But this is also a reply to several of the other posts in this thread. Ear training is real, and is something that people interested in sound reproduction either do formally, or just pick up on from critical listening. Just as with color acuity, you can find online sites that have testing and training programs, often no cost. Try it!

Yeah, loudness trumps almost everything else. If you want to compare how things sound, make certain you match levels within a half db or so. Our phones have pretty accurate apps for this. (One I especially like is called Audio Tool, which includes function generators, etc.)

As was mentioned, a TS is not a great test bed for op amp comparisons. I’d opt for something more Hi fi, like General Tso, or Transcendence. I’m just about to embark on testing several (OPA2134, 2604 and 275), in the Pot & Kettle I finished last week (which has been almost a revelation to me!). Will include that testing in my build report.