More linear FET amplification

Thread Starter

Patrick Malarkey

Joined Aug 28, 2021
16
Cascode Field Effect Transistors, with the amplified voltage across the Drain Resistor, can be used for straightening the Transconduction Curve for a more linear output in acoustic reproduction. FET amplification is one of the "electronic" reasons for "the older style" instruments having better sound to most musicians. And us. Do you remember the band behind Elvis?
 

Audioguru again

Joined Oct 21, 2019
3,822
The vacuum tube and Fet distortion was one-sided (not symmetrical clipping) which caused harmonics that were even-numbered and were exact double and quadruple of the original undistorted frequencies. Some musicians think that an undistorted sound is "dry".
 

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Thread Starter

Patrick Malarkey

Joined Aug 28, 2021
16
Cascode Field Effect Transistors, with the amplified voltage across the Drain Resistor, can be used for straightening the Transconduction Curve for a more linear output in acoustic reproduction. FET amplification is one of the "electronic" reasons for "the older style" instruments having better sound to most musicians. And us. Do you remember the band behind Elvis?
 

Thread Starter

Patrick Malarkey

Joined Aug 28, 2021
16
Can I ask you a question, since you obviously know a few things I don't know. Do coupling and bypass capacitors in linear amplifiers have the effect of altering an audio signal to a sinusoidal-varying-voltage-signal that mimics the original instrument sound. And was the reason for FET amplified sound preferrence possibly caused by direct coupling used in Tube and FET amps. Those amplifiers used little gate or control grid current which might contribute to a lack of coupling or bypass capacitors being used, thus the preferred sound? Do you understand my meaning of the altering of an audio signal by a passive element and resistance in a circuit (basic sinusoidal waveforms)?
 

Thread Starter

Patrick Malarkey

Joined Aug 28, 2021
16
Can I ask you a question, since you obviously know a few things I don't know. Do coupling and bypass capacitors in linear amplifiers have the effect of altering an audio signal to a sinusoidal-varying-voltage-signal that mimics the original instrument sound. And was the reason for FET amplified sound preferrence possibly caused by direct coupling used in Tube and FET amps. Those amplifiers used little gate or control grid current which might contribute to a lack of coupling or bypass capacitors being used, thus the preferred sound? Do you understand my meaning of the altering of an audio signal by a passive element and resistance in a circuit (basic sinusoidal waveforms)?
Or do you mean voltage divider biasing wasn't used and caused clipping at the smallest end of gate or control grid voltage? Such would have been an almost inconceivable undersight by amplifier design teams.
 

Ian0

Joined Aug 7, 2020
3,752
Can I ask you a question, since you obviously know a few things I don't know. Do coupling and bypass capacitors in linear amplifiers have the effect of altering an audio signal to a sinusoidal-varying-voltage-signal that mimics the original instrument sound. And was the reason for FET amplified sound preferrence possibly caused by direct coupling used in Tube and FET amps. Those amplifiers used little gate or control grid current which might contribute to a lack of coupling or bypass capacitors being used, thus the preferred sound? Do you understand my meaning of the altering of an audio signal by a passive element and resistance in a circuit (basic sinusoidal waveforms)?
For “bypass” I presume you mean ”decoupling” capacitors across the power supply? Their absence may cause unwanted coupling from other parts of the circuit, but not distortion.
Coupling capacitors simply remove any DC offset, so do not make waveforms any more sinusoidal. Unless a very poor ceramic type is used, neither do they introduce distortion, although they may change the shape of very low frequency squarewaves.
Direct coupling is very rarely used in valve amplifiers, mainly because the DC output voltage of each stage is always higher than the DC input voltage.
 

LowQCab

Joined Nov 6, 2012
1,296
This Thread sounds like You are trying to understand Distortion.
It's not clear what You are trying to do.

For Hi-Fidelity reproduction,
zero of the "esoteric" blather makes any measurable difference,
unless You do something unusual,
but then it's no longer Hi-Fidelity.

For Musical-Instrument "Amplifiers",
which are DESIGNED to create Distortion,
You will be creating a single "Effect" which may seriously limit
your options when it comes to creating a particular character of "Tone".

I would suggest that You first spend about a year playing-around with
various Graphic-Equalizers and Compressors first,
they make a huge difference.

For Distortion, any of the recent Software-Amp/Cabinet-Emulators will give you
literally thousands of options, as well as many "Preset-Tones" that are excellent.

When using a Software-Emulator,
a modern, very High-Power, High-Fidelity, Transistor-Amp,
along with a pair of High-Power "PA" Speakers,
will produce any "Tone" you can possibly imagine, and it's also in Stereo.
.
.
.
Larry Carlton, perfection on the first take.
Steely Dan, Don't Take Me Alive
 

Thread Starter

Patrick Malarkey

Joined Aug 28, 2021
16
This Thread sounds like You are trying to understand Distortion.
It's not clear what You are trying to do.

For Hi-Fidelity reproduction,
zero of the "esoteric" blather makes any measurable difference,
unless You do something unusual,
but then it's no longer Hi-Fidelity.

For Musical-Instrument "Amplifiers",
which are DESIGNED to create Distortion,
You will be creating a single "Effect" which may seriously limit
your options when it comes to creating a particular character of "Tone".

I would suggest that You first spend about a year playing-around with
various Graphic-Equalizers and Compressors first,
they make a huge difference.

For Distortion, any of the recent Software-Amp/Cabinet-Emulators will give you
literally thousands of options, as well as many "Preset-Tones" that are excellent.

When using a Software-Emulator,
a modern, very High-Power, High-Fidelity, Transistor-Amp,
along with a pair of High-Power "PA" Speakers,
will produce any "Tone" you can possibly imagine, and it's also in Stereo.
.
.
.
Larry Carlton, perfection on the first take.
Steely Dan, Don't Take Me Alive
This Thread sounds like You are trying to understand Distortion.
It's not clear what You are trying to do.

For Hi-Fidelity reproduction,
zero of the "esoteric" blather makes any measurable difference,
unless You do something unusual,
but then it's no longer Hi-Fidelity.

For Musical-Instrument "Amplifiers",
which are DESIGNED to create Distortion,
You will be creating a single "Effect" which may seriously limit
your options when it comes to creating a particular character of "Tone".

I would suggest that You first spend about a year playing-around with
various Graphic-Equalizers and Compressors first,
they make a huge difference.

For Distortion, any of the recent Software-Amp/Cabinet-Emulators will give you
literally thousands of options, as well as many "Preset-Tones" that are excellent.

When using a Software-Emulator,
a modern, very High-Power, High-Fidelity, Transistor-Amp,
along with a pair of High-Power "PA" Speakers,
will produce any "Tone" you can possibly imagine, and it's also in Stereo.
.
.
.
Larry Carlton, perfection on the first take.
Steely Dan, Don't Take Me Alive
 

Thread Starter

Patrick Malarkey

Joined Aug 28, 2021
16
LowQcab
To respond to you, I would like to get away from processed acoustics. From the studio recording to home playback, I like natural but good, vocals and "deep or rich" instumentals, the processed version sticks in my ears worse than an elbow. For years I've heard musicians voice their preference for the old style sounds of the 1950's instruments, to me that's FET amplified instruments.
The harmonics to the fundamental frequencies of instruments vary from one instrument to the other, in their intensity but not so much the fundamental note frequency. So the question arises, does non-linear amplification maintain musical sound quality better than linear bipolar amplification and if so how/why?
All in the quest for better sounding audio enjoyment.
 

Ian0

Joined Aug 7, 2020
3,752
The first working JFET appeared in 1953. I would doubt they were commercially available before the 1960s, so all 1950s music would be valve amplified, and microphones would have been transformer-coupled.
JFETs and Valves would both give a similar spectrum of distortion, mainly 2nd harmonic for preamp stages. As transistors became cheaper more could be used, giving more gain, more feedback and lower distortion. Preamp stages were still class A.
In 1975 came the NE5534, which is still one of the best even though it's more than 40 years old.
The processed sound has very little to do with distortion, it's caused by the effects of noise-gates (which don't operate fast enough or turn off too early, and miss the beginnings and ends of phrases), pitch-shifters which put bad singers back in tune, devices to shift samples in time for singers who can't keep time and the general use of sampled music.
Real music, simply and properly mixed and unprocessed still sounds good.
 

Thread Starter

Patrick Malarkey

Joined Aug 28, 2021
16
All in the quest for better sounding music, IanO.
IanO,
I'm trying to understand my assumed agreement between musicians,
of old style instruments having better sound quality than their modern counterparts. Also I'd like to let you know that because of site-peculiarities and hardware differences I'm finding it difficult to spell my words properly "let alone" convey anything with much thought.
 

Thread Starter

Patrick Malarkey

Joined Aug 28, 2021
16
The first working JFET appeared in 1953. I would doubt they were commercially available before the 1960s, so all 1950s music would be valve amplified, and microphones would have been transformer-coupled.
JFETs and Valves would both give a similar spectrum of distortion, mainly 2nd harmonic for preamp stages. As transistors became cheaper more could be used, giving more gain, more feedback and lower distortion. Preamp stages were still class A.
In 1975 came the NE5534, which is still one of the best even though it's more than 40 years old.
The processed sound has very little to do with distortion, it's caused by the effects of noise-gates (which don't operate fast enough or turn off too early, and miss the beginnings and ends of phrases), pitch-shifters which put bad singers back in tune, devices to shift samples in time for singers who can't keep time and the general use of sampled music.
Real music, simply and properly mixed and unprocessed still sounds good.
Thanks, you're using some terms I'm not familiar with, my apologies. You seem to have read my comments in which::: I'm having a great deal of difficulty with software or hardsare if hkuvr gkg a public.
<Email was deleted, email will bring the Spambot>
 
Last edited by a moderator:

Ian0

Joined Aug 7, 2020
3,752
The moderators will delete your e-mail address. The forum does do private messages. I'm happy to explain privately or publicly any terms I have used with which you're not familiar.
 

LowQCab

Joined Nov 6, 2012
1,296
LowQcab
To respond to you, I would like to get away from processed acoustics. From the studio recording to home playback, I like natural but good, vocals and "deep or rich" instumentals, the processed version sticks in my ears worse than an elbow. For years I've heard musicians voice their preference for the old style sounds of the 1950's instruments, to me that's FET amplified instruments.
The harmonics to the fundamental frequencies of instruments vary from one instrument to the other, in their intensity but not so much the fundamental note frequency. So the question arises, does non-linear amplification maintain musical sound quality better than linear bipolar amplification and if so how/why?
All in the quest for better sounding audio enjoyment.
.
There is no such thing as "un-processed" Sound, NONE, ZERO,
but there may be certain aspects of a particular type or character of
the numerous forms of processing that You don't care for.

When a high-quality Op-Amp Amplifier is not Clipping,
it does not alter the character of the sound in any way, other than to Amplify it.

When a Class-A-B Transistor-Amplifier is pushed into Clipping,
it will always sound like crap.
That's because it has Symmetrical-Clipping, and creates "Odd-Order-Harmonics". (corrected)

When a Tube-Amp is pushed into Clipping,
the Clipping is "Non-Symmetrical", and creates "Even-Order-Harmonics", ( corrected )
which are generally easier on your Ears,
plus there is a variety of other "Distortion-Anomalies" thrown into the mix
which are generally caused by poor Amplifier design,
which is quite often done on purpose to produce a desired "Tone-Character".

Most Musical Instrument Electronics have terrible Frequency-Response, on purpose.

Older Equipment does not sound "better".
The people who insist upon retaining ~50 or ~60-year-old "Paper & Wax" Capacitors,
( which have been deteriorating for 40 of those years ),
and claiming that these totally defective parts create a "Unique-Tone",
are beyond help or reason.
Then they can't figure out why they keep burning-up Tubes every couple of weeks.
NO-NO don't touch the Capacitors !!!,
just "fix it" so it doesn't burn-up Tubes, ( yeah-right ).

Older Equipment is strictly for bragging-rights, and story-telling,
none of it is "magic".

Experienced usage of Graphic-Equalizers will
achieve around ~60% of the Sound You are looking for,
the rest can be achieved with Software-Emulation, with unlimited possibilities.

Musical-Instrument-Speakers, and their associated Cabinets, are 90% garbage,
and are at least ~50% of Your "Tone" when You do it the old-school way.
They create a tremendous amount of distortion, and have a definite "Character".

The same story applies to Microphones, they're not "magic",
they just have different Frequency-Response-Curves and Pick-Up-Patterns.
.
.
.
 
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Thread Starter

Patrick Malarkey

Joined Aug 28, 2021
16
The moderators will delete your e-mail address. The forum does do private messages. I'm happy to explain privately or publicly any terms I have used with which you're not familiar.
I'm going to post on a different device, hopefully more favorable to writing. You can look for the name Patrick Malarkey, as of this moment zero posts. Also, I'm not an engineer, just familiar with technician level topics, a music lover, and a concept definition person. I'm also known to be creative, maybe to the fanciful extent, but tempered with at least some thought. Ill need at least 5 hours to post on the other device, but you can expect that post before retiring this Friday evening. David E. Furlong
 

Audioguru again

Joined Oct 21, 2019
3,822
LowQCab, are you confusing Even Order and Odd Order?
You wrongly said that "Symmetrical clipping creates Even Order harmonics" instead of correctly saying odd harmonics.
You wrongly said that "Non-Symmetrical clipping creates Odd-Order-Harmonics" instead of correctly saying even harmonics.

Odd harmonics sound bad and even harmonics are musical but both are added distortion.
I agree that old electronics cut highs and lows that some people say "sounds warm".
Some people like the old sounds that had added even harmonics and no highs and lows (like an old AM radio?).

I looked up the definition of "deep and rich sounds" and vocabulary.com said "Resonant".
A lousy old speaker fed from an old tubes amplifier sounded boomy and resonant because the damping factor was poor.

True hifi sounds dull and dry to some old people.
 
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