Linear FET Amplification question.

Thread Starter

PatrickMalarkey

Joined Oct 2, 2021
111
IanO I have a general question for you, it's a request for your opinion on the issue I have about linear FET amplifiers and their merit if any of passing those harmonics that distinguish the various musical instruments. Here is my request of your opinion: Is there much of a chance that an all FET amp will not suppress those harmonics/intensities that help human hearing differentiate the various instruments; such that the FET amp (if linear) would be better than the Bipolar amp?
 

LowQCab

Joined Nov 6, 2012
1,931
You could have used a private message rather than making your question Public.

There is no such phenomenon as a Hi-Fidelity-Amplifier "suppressing Harmonics" or, "intensities", period.
.
.
.
 

Thread Starter

PatrickMalarkey

Joined Oct 2, 2021
111
You could have used a private message rather than making your question Public.

There is no such phenomenon as a Hi-Fidelity-Amplifier "suppressing Harmonics" or, "intensities", period.
.
.
.
I would have used a private line, but I don't know how to secure one, and I really don't want a lecture on it. Try to understand the need to keep replies respectful, posts responsible. The world turns a little more peaceably that way.
 

LowQCab

Joined Nov 6, 2012
1,931
I would have used a private line, but I don't know how to secure one, and I really don't want a lecture on it. Try to understand the need to keep replies respectful, posts responsible. The world turns a little more peaceably that way.
Simply click on the person's Avatar to send a Private-Message.
.
.
.
 

Audioguru again

Joined Oct 21, 2019
4,543
A high fidelity amplifier has a flat wide frequency response and very low distortion.
The flat wide frequency response passes all harmonics without suppressing or boosting any of them.
The low distortion adds nothing to the signal making it pure.
Then a high fidelity bipolar transistors amplifier or a Fet transistor amplifier sound the same.
 

BobTPH

Joined Jun 5, 2013
4,785
You are also confusing the linearity of the active device with the linearity of the entire circuit. Tubes, as a device, are more linear than any kind of transistor, but today’s transistor amps are far better than the typical tube amp.

Bob
 

AnalogKid

Joined Aug 1, 2013
9,985
Is there much of a chance that an all FET amp will not suppress those harmonics/intensities that help human hearing differentiate the various instruments; such that the FET amp (if linear) would be better than the Bipolar amp?
No. As in your other thread, no. There is no chance.

Field effect transistors are not magical. They have some properties that are identical to bipolar transistors, and some that are different. But none of the properties of either transistor type "suppress harmonics", and if you start a third thread, the answer will be the same. We don't know where you got your ideas about FET amplification, or what harmonics are and where they come from, but they are incorrect.

A completely horribly-sounding amplifier can be made out of all JFETs, all MOSFETs, a mix of both FET types, etc. And, a sweet and beautiful-sounding amp with perfect reproduction capabilities can be made out of bipolar transistors costing pennies. It is the topology and the engineering of the overall circuit design that sets the tonal properties of an amplifier.

ak
 

Ya’akov

Joined Jan 27, 2019
5,559
"High fidelity" amplifiers are defined by the fact that the produce output as close as possible to the input. The recording, microphone, or other input fed to a genuinely high fidelity amplifier will be reproduced with as close to no additions by the amplifier itself, and with as close to all of the content of the source as practical devices and current designs permit.

This is generally true, no matter which active amplification elements are chosen.

In practice, every amplifier adds distortion in various dimensions. The type and extent of this distortion are generally engineering tradeoffs. If the goal is accurate reproduction of timbre, the amplifier well designed for that function will do the best job for the cost permitted to the (competent) designer. The choice of amplifying device will determine other aspects of the design, not success at the goal.

On the other hand, most modern devices in the reproduction chain are not targeting high fidelity, they are designed to "sound good", focusing on producing subjectively "better" sound, which is not the same thing as accurate reproduction of timbre per se. They have even power response providing noticeable output in the bass, midrange, and treble ranges (this is why many speakers are 3-way design). They produce high dynamic range and large bass signals. The avoid distortion that is detectable as coming from the amps and speakers, which is not the same as distortion that "sounds good".

It is like food. "Good food" can have two definitions: something that allows the eater to experience the subtle flavors of the ingredients and the variety of them, and something that is highly seasoned and stimulates the palate by targeting specific aspects people are known to "enjoy".

This approach was pioneered by AR (Acoustic Research) in the US, and people will report that it "sounds better" because the basis for how good it sounds is not its ability to reproduce timbre accurately but to please the brain with something that requires no reference.

Sorry for the longwinded and sightly off-topic reply. We now return to our regularly schedules postings.
 

LowQCab

Joined Nov 6, 2012
1,931
Yeah but if you do an experiment with a lowly BJT, and investigate the qualities of
the "Magic-Blue-Smoke" that it produces when it blows, you will find only ordinary "Blue-Smoke"
just like so many other Electronic-Devices produce,
but when a JFET blows it produces a wonderfully Golden-Colored-Smoke that actually smells quite pleasant,
this is undeniable PROOF that they have "Magical-Properties"
not possessed by any other plain-old "ordinary" type of Semi-Conductor.
Therefore they are, without a doubt, the "Holy-Grail" of High-Fidelity, and their
prominence in the field of Audio-Reproduction must never be questioned.
.
.
.
 
Top