Diodes for dummies?

edo

edo

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I had to install the new axe edit to realize how many options each drive now offers as far as diodes and clipping. Now what? I mean, how do they affect the sound? Any info / rule we might take advantage of other than randomly experiment with different types on different models?
 
the weaker the diode (forward voltage something something) the more (earlier) it clips. But if you stack more diodes in series, it raises the clipping point (higher voltage) so it clips less, but same type of clipping. Positive vs negative, could not begin to speculate yet, but I hear a difference with more on + side vs more on.- side.

LEDs are strongest (highest clipping point) so they clip less (later) than something else. Different materials/construction clip different ways.
 
shatteredsquare said:
Basically diodes go on the end and they only tolerate so much signal, anything over that gets clipped. But stringing them together in series raises their combined clip level tolerance, so less clipping.
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Is it series or parallel? In the schematic Cliff posted, it was parallel. Adding more diodes reduces the clipping so I assumed that meant the current was split amongst the diodes. Placing them in series would have the same current flow...
 
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shatteredsquare said:
Why would it sound different to have 4 on the + side and 1 on the - side, vs 4 on the - side and 1 on the + side? Positive pushes the speaker out, and negative pushes the speaker in??
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It will basically sound the same, unless something else down the chain processes the sound asymmetrically too (the amp block likely does)

PS: even the drive itself if it has a non correctly biased transistor or opamp.
I assume the bias parameter in the axe has an influence on that too.
 
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I was referring to motor movement, a clip occurring on the positive side would be a clip moving the motor outward, vs a clipping on the negative side would be a clip jumping the motor inwards, inwards motor movement being more muffled, less as loud? I'm brainstorming out loud.
 
shatteredsquare said:
I was referring to motor movement, a clip occurring on the positive side would be a clip moving the motor outward, vs a clipping on the negative side would be a clip jumping the motor inwards, inwards motor movement being more muffled, less as loud? I'm brainstorming out loud.
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Your ears don't care for the phase of the signal (in absolute terms at least, phase difference between the two ears is important for spacial localization of the sounds).
If you flip the phase of a signal you won't hear any difference.

Even if you have a signal that's only positive (imagine half sine wave repeating, IOW a signal clipped at 0V on the negative side) the speaker would still move back and forth, the only thing that changes when you flip the phase is its average position (while moving) relative to its rest position. But that doesn't change the pressure wave produced.

PS: I don't know how a sealed enclosure could affect that though.
I mean, if the cab is really "sealed", when the speaker move backwards AFAIK it finds more resistance due to the air pressure increasing inside the cab and probably can't move inward as much as it moves outward for the same voltage applied.
 
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shatteredsquare said:
Why would it sound different to have 4 on the + side and 1 on the - side, vs 4 on the - side and 1 on the + side? Positive pushes the speaker out, and negative pushes the speaker in??
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In real amp saturation and cut off (positive and negative part of the signal) have different clipping. Feeding an assymetric signal into next stages led to different clipping (harmonic distortion). This, and the filtering, are the foundation of the gain staging system of guitar preamp. To cut a long story short, only Cliff could reply properly. :)
 
∞Fractals said:
Perhaps we can get a Cliff’s Note on this subject, although he might be working on other priorities atm.
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Your comment got me thinking - what is left to do? Optimize code to run quicker? Add a few more guitar and bass amps? Add more of each block? Add a few more oddball but cool effects like the FreqOut? Apart from small things and oddities it is a pretty complete box right now!
 
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App12 said:
Your comment got me thinking - what is left to do? Optimize code to run quicker? Add a few more guitar and bass amps? Add more of each block? Add a few more oddball but cool effects like the FreqOut? Apart from small things and oddities it is a pretty complete box right now!
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Good gobs man! Don’t stop innovation !!!

What ever he may think of… allow him to continue. Look how far we’ve come. Why stop now?

By the way, my understanding is that modeling new amplifiers is no small feat.
 
App12 said:
Your comment got me thinking - what is left to do? Optimize code to run quicker? Add a few more guitar and bass amps? Add more of each block? Add a few more oddball but cool effects like the FreqOut? Apart from small things and oddities it is a pretty complete box right now!
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I think @∞Fractals was referring to how diode clipping works.
 
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