My ears and about 50 years of listening to music that hasn't necessarily the best sound. And two musicians that liked the older style amplification. There was a notable switch to the bipolar amp in 1960, replacing the FET amplifier. You got anything you'd like to say?

Correct me if I'm wrong, but did we ever go through a phase of JFET amplification in the 1950s? My understanding of the history is that bipolar amplifiers replaced valve amplifiers, and JFETs were always a bit of a rarity. True, early bipolar amplifiers were terrible, because designers were trying to use valve designs with the new devices, and it took a while to work out how to eliminate crossover distortion, which wasn't helped by H.C.Lin patenting the quasi-comp design.

 

My ears and about 50 years of listening to music that hasn't necessarily the best sound. And two musicians that liked the older style amplification. There was a notable switch to the bipolar amp in 1960, replacing the FET amplifier. You got anything you'd like to say?

Let's all bow down to your ears. They're clearly made of solid gold.

 

A high fidelity amplifier has a flat wide frequency response creating the same levels of all the harmonics as the input signal.
It produces distortion less than people can hear then nothing bad is added.

Old amplifiers produced drooping levels of low and high frequencies that some people like. Vacuum tubes and Fets produce extra even harmonics distortion that some people say sound musical. Then the output sounds different than the input which is poor fidelity.

 

Single phase AC can only ever produce an oscillating magnetic field. To start a motor, it requires a rotating magnetic field. The capacitor produces a phase advance in the starting winding, which makes a rotating magnetic field. Because the stator lags behind the magnetic field, once the motor is rotating a single oscillating field will keep it rotating in the same direction until the load torque creates too much lag.

Well I've read and understand most of what you've written, but I strongly disagree with you about the reason for that capacitor. I maintain it's to prevent the current surge in both the customer and power company wiring. And initially helps tremendously to increase the impedance by the motor-shunt-capcitor at low RPMs. At higher "running" RPMs it actually carries a "wasted" current (energy) and is thrown out of it's connection with the motor.
It's action of impeding voltage is that of a shunt L/C Resonance with the motor, as are the reason power distributor's use huge capacitors in shunt with their transformer secondaries, for customers who run enough motors to justify the cost of adding the capacitors. Yes there must be a certain amount of Farads to set-up the resonance, and that value varies with the number of motors driven by the transformer. Therefore distributors have their ways of disconnecting one or more of their capacitors.

 

As is my understanding, such frequencies are suppressed by linear Amplification

Where did you learn that bit of misinformation?
That's the opposite of what linear amplification does.
Accurate linear amplification means that all the components of the audio signal are amplified linearly (i.e. without modification).

 

Never pay any attention to what a Guitar-Player says about Electronics,
the Keyboard-Player "may" know a little about Electronics and how to create the desired Distortion.

NEVER take advice from anyone who fancies themselves as an "Audiophile",
you will be misled into all sorts of unheard-of-adjectives that basically only prove that
they are trying to elevate themselves above the disdainful masses,
who simply "don't understand", or, "can't appreciate"
the finer nuances of true-perfection in sound-reproduction.

After You spend decades working-out where the actual problems are in
the current "State-of-the-Art" Sound-Systems,
You will ultimately come to the conclusion that the Amplifier is
the most insignificant of a whole variety of problems which should be addressed first.

And, the "Big-Fat-Pink-Elephant-in-the-Room", is the Room its self.
.
.
.

 

There was a notable switch to the bipolar amp in 1960, replacing the FET amplifier.

No.

Throughout the 60's (not just in 1960) there was a notable switch to transistor amplifiers, replacing ***tube*** amplifiers. The vast majority of the solid state amps were bipolar, because power FETs were rare and expensive. They had the advantage of being inherently immune to thermal runaway, but that phenomenon became so well understood so quickly that FETs didn't become financially viable (in a broad sense, not in specialty devices) until the 70's. I was there.

ak

 

As is my understanding, such frequencies are suppressed by linear Amplification, and I can be quite wrong and appreciate my feedback.

Well, I agree - you are quite wrong, and have it exactly backwards.

A linear amplifier, pretty much by definition, is linear. Not logarithmic, not clipping, not frequency-filtering. Just plain linear. Nothing can pass all of the harmonics of musical instruments better than a linear amplifier designed for the job -

with an input voltage range that can handle the incoming audio signal without clipping
with an input stage that does not introduce harmonic distortion due to mismatched transconductances in the input transistors
with a voltage gain stage that has the bandwidth not to attenuate the higher-order harmonics
with a feedback loop that has enough low frequency response not to squash the bass
with enough open-loop gain (the gain-bandwidth product) to have at least 20 dB of negative feedback at the highest frequency of interest
with an output stage that can drive its load without clipping and without crossover distortion
and other stuff

I don't know where you got your idea of what the term "linear amplifier" means, but that source is incorrect.

ak

 

Correct me if I'm wrong, but did we ever go through a phase of JFET amplification in the 1950s? My understanding of the history is that bipolar amplifiers replaced valve amplifiers, and JFETs were always a bit of a rarity. True, early bipolar amplifiers were terrible, because designers were trying to use valve designs with the new devices, and it took a while to work out how to eliminate crossover distortion, which wasn't helped by H.C.Lin patenting the quasi-comp design.

I don't really know for certain about the first FETs, but for some reason I'm of the side that pins them to around 1950, and as a deliberate development of a solid state version of the vacuum )tube. That puts them in use by Elvis and the bigger names like Buddy Holly, of the 50's. Their sound is distinctly pleasant, even with playback on today's bipolar amp. so as far as what I would GUESS, yes there was about 10 years of use here in the States. I don't really have any idea about Great Brittain, but because of technological alliances between countries, I would figure yes, all the way to the origin country of the FET.

 

I went to a demo of some new Name Brand speakers. They were normal looking large speakers and they sounded great. Then two pretty young ladies removed fake covers over the speakers revealing fairly small speakers that were playing. After checking out the ladies I looked all over for the sub-woofer I heard but there was none. The big surprise gave me goose bumps.

Singers who use Auto-Tune pitch correction give me the creeps. Cher in 1998 sang I Believe with a voice that sounded like a keyboard. Drake and Justin Bieber obviously use Auto-Tune. I am glad that Adele doesn't.

 

Well, I agree - you are quite wrong, and have it exactly backwards.

A linear amplifier, pretty much by definition, is linear. Not logarithmic, not clipping, not frequency-filtering. Just plain linear. Nothing can pass all of the harmonics of musical instruments better than a linear amplifier designed for the job -

with an input voltage range that can handle the incoming audio signal without clipping
with an input stage that does not introduce harmonic distortion due to mismatched transconductances in the input transistors
with a voltage gain stage that has the bandwidth not to attenuate the higher-order harmonics
with a feedback loop that has enough low frequency response not to squash the bass
with enough open-loop gain (the gain-bandwidth product) to have at least 20 dB of negative feedback at the highest frequency of interest
with an output stage that can drive its load without clipping and without crossover distortion
and other stuff

I don't know where you got your idea of what the term "linear amplifier" means, but that source is incorrect.

ak

Yes well that's

Well, I agree - you are quite wrong, and have it exactly backwards.

A linear amplifier, pretty much by definition, is linear. Not logarithmic, not clipping, not frequency-filtering. Just plain linear. Nothing can pass all of the harmonics of musical instruments better than a linear amplifier designed for the job -

with an input voltage range that can handle the incoming audio signal without clipping
with an input stage that does not introduce harmonic distortion due to mismatched transconductances in the input transistors
with a voltage gain stage that has the bandwidth not to attenuate the higher-order harmonics
with a feedback loop that has enough low frequency response not to squash the bass
with enough open-loop gain (the gain-bandwidth product) to have at least 20 dB of negative feedback at the highest frequency of interest
with an output stage that can drive its load without clipping and without crossover distortion
and other stuff

I don't know where you got your idea of what the term "linear amplifier" means, but that source is incorrect.

ak

Well, you come across as somebody that knows what they're talking about and doing with my matters of acoustics. I'm going to direct any further efforts to something besides linear FET amplification, and by the way thank you for taking time to share your "thinks".

 

Ian

Correct me if I'm wrong, but did we ever go through a phase of JFET amplification in the 1950s? My understanding of the history is that bipolar amplifiers replaced valve amplifiers, and JFETs were always a bit of a rarity. True, early bipolar amplifiers were terrible, because designers were trying to use valve designs with the new devices, and it took a while to work out how to eliminate crossover distortion, which wasn't helped by H.C.Lin patenting the quasi-comp design.

IanO I wrote a response to you, so hope you can find it. This site and all the replies are terribly difficult to navigate.

 

I went to a demo of some new Name Brand speakers. They were normal looking large speakers and they sounded great. Then two pretty young ladies removed fake covers over the speakers revealing fairly small speakers that were playing. After checking out the ladies I looked all over for the sub-woofer I heard but there was none. The big surprise gave me goose bumps.

Singers who use Auto-Tune pitch correction give me the creeps. Cher in 1998 sang I Believe with a voice that sounded like a keyboard. Drake and Justin Bieber obviously use Auto-Tune. I am glad that Adele doesn't.

Audioguru, if you want a recommendation about good sounding affordable speakers, I'll write you some directions for something I did with two pairs of speakers. It's a reversible way of setting-up a phase-driven mid-range speaker in a 3 way system, ported or acoustic suspension. To my ears the sound is much better.

 

Never pay any attention to what a Guitar-Player says about Electronics,
the Keyboard-Player "may" know a little about Electronics and how to create the desired Distortion.

NEVER take advice from anyone who fancies themselves as an "Audiophile",
you will be misled into all sorts of unheard-of-adjectives that basically only prove that
they are trying to elevate themselves above the disdainful masses,
who simply "don't understand", or, "can't appreciate"
the finer nuances of true-perfection in sound-reproduction.

After You spend decades working-out where the actual problems are in
the current "State-of-the-Art" Sound-Systems,
You will ultimately come to the conclusion that the Amplifier is
the most insignificant of a whole variety of problems which should be addressed first.

And, the "Big-Fat-Pink-Elephant-in-the-Room", is the Room its self.
.
.
.

Hmhmph

 

I have not purchased or listened to a speaker system for sale for many years because I made my own speaker systems years ago and a few still work great today. My first speaker system was made by Acoustic Research in 1964.

I have an 18" 900W subwoofer still in its box that has never been played. I never designed and built an enclosure for it.

 

I have not purchased or listened to a speaker system for sale for many years because I made my own speaker systems years ago and a few still work great today. My first speaker system was made by Acoustic Research in 1964.

I have an 18" 900W subwoofer still in its box that has never been played. I never designed and built an enclosure for it.

The AR-6 YES !!!!

Sell the 18 and get 2-Eminence-"Lab-12"s from Parts-Express.
Here's the Cabinetry You'll want ...........
https://billfitzmaurice.info/THT.html
https://billfitzmaurice.info/T60.html
.
.
.

 

There are a few articles that focus on low noise Jfet transistors how they might be used to make a low distortion audio amplifier.
The operating point is a good start, getting a nice looking sine wave with low total harmonic distortion can be a challenge.
https://www.linearsystems.com/lsdata/others/LSK489_Application_Note.pdf

There is a DIY THD analyzer, magazine article with schematic and pcb. Other approach is to use FFT or
a simulator in order to get feedback on how excellant the JFET amplifier really is clean.
http://www.cordellaudio.com/instrumentation/thd_analyzer.pdf

 

I don't really know for certain about the first FETs, but for some reason I'm of the side that pins them to around 1950, and as a deliberate development of a solid state version of the vacuum )tube. That puts them in use by Elvis and the bigger names like Buddy Holly, of the 50's.

Nope. All of the big names in the 50's used 100% tube gear 100% of the time.

Responding to this and other posts ...

The first JFET was demonstrated in the early 50's. Practical, reliable devices for sale took about 5 years. Professional audio equipment using JFETs took a couple more years to appear, but were rare. And, these were not power devices.

The MOSFET wasn't invented until 1959, with reliable power devices coming many years later. By the end of the 60's they were creeping into audio gear, again in less popular and very expensive amps.

So, Buddy and Elvis? No.

BTW, the two guys who invented the transistor (yes, partly as a replacement for the vacuum tube, and partly as a replacement for mechanical switches in exchanges) were supposed to be working on a FET because it was their boss's pet project. They couldn't get it to work, so they invented the bipolar junction transistor, knocked off work early, and went Christmas shopping. Really. And, really pissed off the boss.

ak

 

not to call you a liar,

Nice.

You do know that we are talking about events in the 20th century, right? It wasn't all that long ago. And, people wrote stuff down. AND, some of those people lived into the 1980's, and could talk.

I can see many of your statements as coming from one of two places. A) you're a troll. b) you're lazy. There are dozens of sites dedicated to the histories of electronic devices, but any 6th grader knows how to spell "transistor" and use Wikipedia.

The development of the transistor and its later variants wasn't exactly a secret. In fact, it was in all the papers. And the Journal of the IEE (their name back then). And the Proceedings of the IEEE. And Electronics. And Popular Electronics. And Radio-Electronics. And Electronics Illustrated. And Wireless World (yes, they heard about it in Europe). I have some of the original issues, as do many of the regulars around here and on other forums.

You can read all about it here:

https://www.hobbymagazines.org/electronics/

https://archive.org/search.php?query=electronics+magazine+rack&and[]=mediatype:"collection"

https://worldradiohistory.com/

https://en.wikipedia.org/wiki/History_of_the_transistor

ak

 

but I strongly disagree with you about the reason for that capacitor. I maintain it's to prevent the current surge in both the customer and power company wiring. And initially helps tremendously to increase the impedance by the motor-shunt-capcitor at low RPMs. At higher "running" RPMs it actually carries a "wasted" current (energy) and is thrown out of it's connection with the motor.

There's a reason it's called a "motor start capacitor".

the reason power distributor's use huge capacitors in shunt with their transformer secondaries, for customers who run enough motors to justify the cost of adding the capacitors. Yes there must be a certain amount of Farads to set-up the resonance, and that value varies with the number of motors driven by the transformer. Therefore distributors have their ways of disconnecting one or more of their capacitors.

That's just power factor correction. If the power factor is corrected closer to unity, the secondary current reduces. This reduces the heating in the transformer allowing the use of a smaller transformer. The power companies prefer that the power factor is corrected at source (i.e.. where the low power factor load is operating) because that reduces current in their cables.
Resonance it to be avoided as it would lead to increases in supply voltages. There is always enough resistive load to keep the resonance damped.