john curl said:
G'day John.
Here's an amplifier that doesn't contain a single FET:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=96853&highlight=
I'd like to see an "all FET perfection" amplifier with comparable THD performance.
Despite the often repeated FET square-law conformance better than BJT exponential charachteristic furphy, emiter-degenerated BJT's generally operate with significantly better to vastly better linearity than do FET's, and their gm is better too.
It's is not the devices that necessarily make a good amplifier - it is what the designer does with them.
Cheers,
Glen
G.Kleinschmidt said:
Check this out by Charles Hansen of Ayre audio...all VFET
http://www.diyaudio.com/forums/attachment.php?s=&postid=334963&stamp=1077770119
Kanwar
Upupa Epops said:
While it may be argued actual music may elicit modes of distortion not readily exited with various test signals, there is a definitive tool to unmask them and it is the null test with actual speaker loads.
No matter the technology, if different amplifiers pass the null test (this losely meaning spurious products both in amplitude and spectral structure below certain thresholds), then there should not be audible differences.
To substantiate a claim regarding which technology is "better" I think this kind of objective test - which could be widely accepted in both method and results - could provide a definitive veredict if there is one.
Rodolfo
Glen,
You have a history of commenting adversely on circuits you've never heard. I would suggest this is inappropriate; you cannot be credible without carefully auditioning everything you condemn, and besides, if you do this you might be able to correlate the sonics with the circuit and come to a few interesting conclusions.
Incidentally, I do agree with you about BJTs over FETs.
Your derisory comment about 'musical instrument' amused me. Single ended tube amplifiers are known to be colored, and lie in this category, yet people pay large sums of money for them. Why is this? Are you telling them they are wrong? You really need to try to understand this market. The conjunction of music and engineering requires a knowledge of psycho-acoustics, and there is plenty of evidence for this in the market.
Cheers,
Hugh
You have a history of commenting adversely on circuits you've never heard. I would suggest this is inappropriate; you cannot be credible without carefully auditioning everything you condemn, and besides, if you do this you might be able to correlate the sonics with the circuit and come to a few interesting conclusions.
Incidentally, I do agree with you about BJTs over FETs.
Your derisory comment about 'musical instrument' amused me. Single ended tube amplifiers are known to be colored, and lie in this category, yet people pay large sums of money for them. Why is this? Are you telling them they are wrong? You really need to try to understand this market. The conjunction of music and engineering requires a knowledge of psycho-acoustics, and there is plenty of evidence for this in the market.
Cheers,
Hugh
AKSA said:Glen,
Oh lighten up.
I asked for an all-FET amplifier design with comparable THD performance to the “ExtremA” amplifier, what Kanwar presented isn’t even close – so I’m entitled to have a giggle.
Also, I don’t have to listen to a SS amplifier when it is sufficiently evident from its design to conclude wether or not the design qualifies as “HiFi” or not. High fidelity means just that – minimal if any audible coloration. A lot of vacuum tube tube amplifiers are deliberately designed not to be HiFi. Some like it that way, but so what? I don’t know what point you are trying to make by mentioning valve amplifiers, besides demonstrating your obtuseness.
As for the coloured sound of valve amplifiers, I don’t need edification from you. I’m willing to bet $21.57 that I own more valve amplifiers than you do.
So what about the large sums of money countless people are willing to spend on “psychic hotlines” or for magnets and crystals and other nick-knacks for gluing to one’s forehead to cure ailments from indigestion to one’s marital problems? Talk about a totally useless line of argumentation
As for my needing to understand the market with which the likes of you and others are involved, I understand it perfectly well enough – BS sells.
Cheers,
Glen
Hi Glen,
Charles Hansen is one of the finest designer of Hi-End audio I have ever seen...
The schematic was of Ayre audio V3x amp, A zero feedback all VFET design......
The problem with you is very well illustrated by Hugh....Thanks to him...
Have you ever tried VFET, if not then who gave you the right to comment upon a VFET amp without having any experience of designing it ...
Kanwar
Charles Hansen is one of the finest designer of Hi-End audio I have ever seen...
The schematic was of Ayre audio V3x amp, A zero feedback all VFET design......
The problem with you is very well illustrated by Hugh....Thanks to him...
Have you ever tried VFET, if not then who gave you the right to comment upon a VFET amp without having any experience of designing it ...
Kanwar
Workhorse said:
Well, I agree that Charles Hansen may well be a competent audio designer, and that amplifier may even perform very well for what it is – a zero feedback all V-MOSFET amplifier.
Now you can recite that again if you want, and even further elaborate on what a closed-minded, nasty and horrible person I am, however, that is all beside the point. That amplifiers THD performance is hundreds of times worse that the design I cited as a reference of what can be achieved with BJT’s, so I hardly see its existence as being evidence in support of the dubious and thus far largely unsubstantiated assertion put forth by Borbely and others that BJT’s must be designed out of our amplifiers for the best sonic performance. Like, that’s even something that Hugh and I agree on.
Cheers,
Glen