Thank you RJM1.
Can you comment a bit what your circuit does
and how and why it works.
These guys with electric guitars have done this for ages.
Also thanks to jerluwoo.
I will try your circuit.
Can you comment a bit what your circuit does
and how and why it works.
These guys with electric guitars have done this for ages.
Also thanks to jerluwoo.
I will try your circuit.
The three transistors each amplify signal and their output is 180 degrees out of phase with the input (plus some delay). this signal is added to the input signal which cancels most of the fundamental. The signal is then amplified by the op-amp to give approximately the same output level as the input with greatly increased distortion products.
(Vin -(Vin + distortion))* gain = output
(Vin -(Vin + distortion))* gain = output
Yes, we can add distortion to produce a "favorable" sound. But distortion is distortion, whatever the order.
But when distortion is already adequately low, then I'll pay attention to the harmonic structure. I.e. not wanting even extremely lower THD by sacrificing harmonic structure.
The "poor" ccs as posted by wahab, will create good harmonic structure but the distortion is intolerable. But it has one merit. When the circuit has poor stability, I will check if that ccs will solve my problem.
Depend on circuit, higher bias will tend to bring not only lower distortion, but also good harmonic structure. So I always check if adding only a few hundred mA will turn the structure positively.
In a bootstrap circuit, a feedback usually connected to the middle of 2 resistors. Connecting the feedback (e.g. the bootstrap cap) closer to the positive rail (instead of to the transistor base) will augment the second order. So 3K3/3K3 can be replaced with 2k2/4k4 or even 1k5/5k1. Usually I use no higher than 3K3 towards the positive rail.
Choice of parts (transistors)
Parts (transistor or opamp) are usually famous for good sound when they tend to produce good harmonic structure, or augmented second order.
When a device tend to produce higher odd order, usually it is very hard to lower the 3rd order so to make a good monotonic structure. But when the device tend to give augmented 2nd order, it is usually easy to lower all of the distortions, or to make a good harmonic structure.
Darlingtons have terrible harmonic structure that it has a reputation for a bad sounding device. Motorola MJ11015 and similar darlingtons are very hard to tweak, but Motorola 2N6284 tend to give good harmonic structure.
For opamps, in arbitrary circuit OPA2134 tend to give augmented 2nd order. It is easy tho to lower the 2nd order without introducing 3rd order in a carefully designed circuit.
OPA111 has even higher tendency than OPA2134 to augment the 2nd order in an arbitrary circuits.
In summary, each transistors have their own "sweet spot". Some wide, some narrow.
Parts (transistor or opamp) are usually famous for good sound when they tend to produce good harmonic structure, or augmented second order.
When a device tend to produce higher odd order, usually it is very hard to lower the 3rd order so to make a good monotonic structure. But when the device tend to give augmented 2nd order, it is usually easy to lower all of the distortions, or to make a good harmonic structure.
Darlingtons have terrible harmonic structure that it has a reputation for a bad sounding device. Motorola MJ11015 and similar darlingtons are very hard to tweak, but Motorola 2N6284 tend to give good harmonic structure.
For opamps, in arbitrary circuit OPA2134 tend to give augmented 2nd order. It is easy tho to lower the 2nd order without introducing 3rd order in a carefully designed circuit.
OPA111 has even higher tendency than OPA2134 to augment the 2nd order in an arbitrary circuits.
In summary, each transistors have their own "sweet spot". Some wide, some narrow.
2nd harmonic is a frequency doubling.
If you DSP that in the time domain,
need not suffer 3rd or higher or IMD.
In immediate terms: A full wave
rectifier, followed by square law
distortion produces a pure 2nd.
But only if the input was a pure tone.
If a mix of tones, you get IMD also...
In physical terms, the Sitar effect:
String touching a Jawari each half cycle.
If you DSP that in the time domain,
need not suffer 3rd or higher or IMD.
In immediate terms: A full wave
rectifier, followed by square law
distortion produces a pure 2nd.
But only if the input was a pure tone.
If a mix of tones, you get IMD also...
In physical terms, the Sitar effect:
String touching a Jawari each half cycle.
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The circuit above is half a Gilbert cell, with deliberate and controlled leakage from one port
Hi lineup, you revived your own thread from being dead.
This is what i do: i use tube pre with just the right amount of second harmonic before the clean solid state buffer. No global feedback. Very happy with the sound.
I do not want to open can of worms, i like my preamplifiers with musical emotional sound. Clean, yet smooth. I am sure others will disagree, saying bs like 'sound reproduction should introduce no distortion'.
I was accused by some bimbos here when i used tube pre with second harmonic distortion, its called effect box by them, that i am insulting the artist! And putting shades on lisa.
Total nonsense.
Fine tuning or voicing or dialing just the right amout of distortion is required if one cares about emotional content of the music.
In the fight between brain and heart, heart is always right.
This is what i do: i use tube pre with just the right amount of second harmonic before the clean solid state buffer. No global feedback. Very happy with the sound.
I do not want to open can of worms, i like my preamplifiers with musical emotional sound. Clean, yet smooth. I am sure others will disagree, saying bs like 'sound reproduction should introduce no distortion'.
I was accused by some bimbos here when i used tube pre with second harmonic distortion, its called effect box by them, that i am insulting the artist! And putting shades on lisa.
Total nonsense.
Fine tuning or voicing or dialing just the right amout of distortion is required if one cares about emotional content of the music.
In the fight between brain and heart, heart is always right.
If you color the sound deliberately your using an effects box. Nothing wrong with that, I use EQ sometimes on playback, but the music is still going thru effects. If a device is transparent its not.
https://en.wikipedia.org/wiki/Effects_unit
https://en.wikipedia.org/wiki/Effects_unit
There are software plugins that will let you play with different amounts of harmonic distortion why not try that.
Wheather you color the sound deliberately, or due to the shortcommings of the design, everything distorts. Every speaker distorts, every amplifier distorts... (excluding extinct halcro)
So when you introduce distortion not deliberately, that does not clasify as effect box?
Actually everybody's using a box effect once a song mastered on a set of active or passive monitors in a controlled recording studio space is listened in a different place played by different amps and speakers...A mastering session can be done on half a million dollar equipment which usually you can't even dream using at home.
There is a tradition in engineering generally, that "engines" should all do something in a clearly defined, measurable way according with specifications, so we can know whether individual products comply with some standard or expectation. Unfortunately, audio and music in particular, is a sensory, cultural and psychological experience, so an amplifier, for example, can meet all the manufacturer's specs but still not satisfy our important, undefined ones and as alluded to above, it's only part of a system that may struggle to satisfy anyway.
Popular brands have all used various design tricks over decades to improve the sound quality and satisfaction we get when we play and hope to enjoy our choice of music. Well, anything that improves a brand's image and sales volume has to be a good thing, regardless of whether their products meet the highest of laboratory standards, if that's what you think should interest buyers. 50 years ago, new audio technology always impressed audio enthusiasts but not so today, whilst there is still a strong trend among them, toward obsolete technologies that mostly suck from a technical POV.
Popular brands have all used various design tricks over decades to improve the sound quality and satisfaction we get when we play and hope to enjoy our choice of music. Well, anything that improves a brand's image and sales volume has to be a good thing, regardless of whether their products meet the highest of laboratory standards, if that's what you think should interest buyers. 50 years ago, new audio technology always impressed audio enthusiasts but not so today, whilst there is still a strong trend among them, toward obsolete technologies that mostly suck from a technical POV.
Interesting topic, i also would like to learn how, I do remember at the time I was still playing with LTSpice, I noticed that if you get a pretty good 2nd harmonic profile the harmonic distortion also increases.
so...following 🙂
so...following 🙂
Sometimes simpler is better.
Perhaps try a spring reverb unit out of a organ or guitar and see if that juices up the sound to your liking.
Spring reverbs add a pleasureable spaciousness to the sound, and are not only distorting but feeding back to some extent...
Should sound fantastic and measure, distorted...
Perhaps try a spring reverb unit out of a organ or guitar and see if that juices up the sound to your liking.
Spring reverbs add a pleasureable spaciousness to the sound, and are not only distorting but feeding back to some extent...
Should sound fantastic and measure, distorted...