we are coming from different directions, its hard to get a handle on how people differ on viewpoints, very hard indeed, the web makes it much harder.
I think you know what I am saying, take a commercial japanese, english, or american transistor amplifier run totally with standing current to keep transistors turned on.
Turn down to the class B point and just above...that's what I am meaning...
but as its probably got feedback not sufficient, then sound quality MAY alter for the worse, its hard for a comparison.
point I was making is I haven't heard a class A commercial transistor amp better a decent AB one.
I'll retire now, explanation made, if insufficient, there is no hope for the human race🙂
I think you know what I am saying, take a commercial japanese, english, or american transistor amplifier run totally with standing current to keep transistors turned on.
Turn down to the class B point and just above...that's what I am meaning...
but as its probably got feedback not sufficient, then sound quality MAY alter for the worse, its hard for a comparison.
point I was making is I haven't heard a class A commercial transistor amp better a decent AB one.
I'll retire now, explanation made, if insufficient, there is no hope for the human race🙂
Sure. Your generalizations are just too wide to be accepted by people who has some other experiences than yours. 😉
Exactly!
Low distortion does not automatically equal a superior experience.
Low distortion amps feeding reference speakers can lead to a quickly fatiguing presentation. If you’re a sound engineering and your goal is to hear every flaw in a recording that’s great. If want to enjoy the experience, that’s not so great.
Plus worrying about .1% is silly. The biggest source of distortion in a quality system (SS and Tube) is usually the room its in. Followed by the speakers.
If it sounds good, enjoy it. Numbers be damned!
I believe that the triode is still the most linear (common) amplifying device made my man.
dave
A pretty nonsensical statement given that the most comprehensive measurements we can make still fall short of telling us what makes a good sounding amplifier -- there are no "proper" distortion measures to look at.
If the only tool you have is a hammer, you treat everything like a nail.
I'm not saying Class A or Class B is better, there are good and bad of both...
dave
I agree mostly
If I'm sound engineering (mixing, mastering) I don't want a fatiguing presentation.
With my tube amps and good speakers, I can hear every flaw, with perfect
imaging, with much less ear fatigue. This results in a better product and a
happier engineer. Another thing is to get beyond near field monitors, aka
glorified headphones, early in the process but that's another discussion.
Worrying about 0.1% isn't silly at all. It's -60db which is well within the dynamic
range capability of everything including some car audio. Mix in .1% of your
favorite car alarm sound track and see how long you can stand it ;-) whoop
whoop dee-doo-dee-doo
It's just that THD is useless as a measure of sound goodness.
Cheers
Michael
I think we're still making slushies. Tubes as devices, specifically the more linear triodes, are to my understanding far more so than transistors. Tube circuits however may or may not be depending on how well the designer conquers the device's (discounting transmitter tubes, etc.) near inability to deliver current.
What transistor is as linear unloaded as a 300B, 12AX7 or 6C45 in their optimum operating ranges?
I agree with you, BTW. It's easier to run a tube in a fairly linear mode than a transistor, certain FETs excepted. See Zen and its progeny. And I agree that the low-order harmonics that predominate in tubes are less irritating than the high order harmonics of most other gain devices. I am not a fan of ignoring some distortion "because it sounds OK" except in guitar amps. If you need a bright amplifier or a reactive interconnect to make your system sound good, then you ought to find out why and fix the culprit, whether it be speaker, preamp, DAC, whatever. My opinion for what its worth.
I was thinking more along the lines of "distortion" is not always car alarms. If an amp has some % THD, but you like the sound.... don't worry about the stat. Distortion is not always a minus, in some cases it is a plus.
I guess I was thinking that < 0.1% can sound bad and > 1% can sound great.
One amp I remember is used a lot in pro audio, the Hafler Pro 5000. It's THD
spec is under 0.1% THD from one watt to 325W/channel into 8 ohms, IMD <
0.01%, etc. This amp has "signal present" indicators, LEDs on the front, that
are driven from op amps tapped into the signal path. So far, so good, but these
op amps (comparators actually) "latch on" by feeding the output signal back to
the input (directly in the signal path), which causes a minute (<0.1% of something)
tick to be added to the signal when these indicators go on and off. They
would impart a very obvious buzz-saw like distortion to the most delicate
passages... The simple fix to pull the chips out, but how was this never caught?
The designers only cared about watts and THD and damping factor.
This is worth reading.
http://www.milbert.com/tstxt.htm
He is talking about tubes v. SS in a recording studio. Not for playback but the ideas are the same. He is basically saying what most here have said, that some kinds of distortion are better tolerated by human ears than others. But then he goes into some details about the nature of the distortion products, at least as it applies to studio mic preamps
This is good too although it does contain some opinion and has some technical errors. But overall not bad and worth reading
http://en.wikipedia.org/wiki/Tube_sound
http://www.milbert.com/tstxt.htm
He is talking about tubes v. SS in a recording studio. Not for playback but the ideas are the same. He is basically saying what most here have said, that some kinds of distortion are better tolerated by human ears than others. But then he goes into some details about the nature of the distortion products, at least as it applies to studio mic preamps
This is good too although it does contain some opinion and has some technical errors. But overall not bad and worth reading
http://en.wikipedia.org/wiki/Tube_sound
I don't think that anyone genuinely interested in "HiFi" sound reproduction is interested in continuously running their amplifier into overload.
As for tube amps Vs SS amps in this regard, run a typical tube amp into overload for too long it certainly won't be sounding nice when the power output valves start operating in class C because of blocking distortion.
In fact, my basic 10W SS class A amp trumps my 10W Williamson in this regard (apparent loudness under overload before becoming too objectionable).
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More likely the latter. For push-pullers; The simple test 0.5dB down from full power/ just off onset clipping into a dummy L should show how good the design is.
richy
Attachments
The VU meters in Ampex AG-440 series do the same. Diode switching noise. A savvy engineer would patch into the headphone jacks which were buzz-free for mixdown. Ampex isn't the only offender, either. Pro equipment is designed rugged and dependable. Sound quality is not always top on the list as long as it's adequate by the standards of the day. Those standards do rise over time. For instance you won't see many sessions being mastered at 16/48 today, the equipment will be set for 24/96 or better. Whether it actually can resolve that bit depth.... well...
Interestingly, the Ampex 350 series (tubes) has the same VU circuit, but nobody heard the buzz. It was buried in the higher noise floor (tape hiss), I guess. Those old 350 & 351 recording amps sell for big bucks on eBay to people who use them as mic preamps. In the day, they weren't considered anything special.
We're all in agreement. The standards of the day, and today, are THD oriented;
the expectation is just for lower and lower THD, for what it's worth. It's appalling
what crud can be added to the sound and still meet <0.1% THD specs.
Unbuffered VU meters are ~7K8 impedance with rectification, so they are only
barely acceptable in 600 ohm circuits; always patched out of the signal path
for mixdown. I'm surprised the 440 decks don't have meter drivers!
Ampex 350/351 are known as a "color" preamp for sure, which explains the
recent popularity. "Warm up your tracks with toobz!"
To get back to speaker distortion, here's a good article on the subject:
Loudspeaker Nonlinearities Causes and Symptoms
Figures 23 and 25 are of particular interest.
~Tom
Loudspeaker Nonlinearities Causes and Symptoms
Figures 23 and 25 are of particular interest.
~Tom
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