Please Read and express your feelings and opinions....
I noticed that lately or maybe for the last five yrs, there is so much arguments,name calling, attacking cables , speakers , components makers and more, more of disagreement with members, even Audio dealers are being attack here...Very few know how to apologize when they are wrong.What can we do as Audiogon members to improve our communication to each other? How to give the informations, recommendation to members who need it? This is without involving Audiogon, any opinion or ideas , For me this is fun and place to learn in audio...thank you all
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Atmasphere 4-19-2018
I've been able to measure effects of fuses and power cords, which has
often put me at odds with some that make apocryphal claims about them,
but also those that I usually regard as 'objectivists' that won't take
anything seriously without good measurements. In the latter case, they
don't seem to want to cause their hand to move and make the
measurements, instead proclaiming that a fuse or power cord can't make a
difference. Without the measurements, their proclamations seem to me as
bad (and for the same reason) as those that make the apocryphal claims.
... Which serves to illustrate, IMO, that when it comes to many of the more controversial things in audio the truth is usually a good deal more nuanced than viewpoints that tend to be expressed by those at or near both extremes of the belief spectrum, and usually lies somewhere in between.
Similarly, others see the pops and ticks, rapid wear, uneven high
frequency performance, limited dynamic range, increased distortion, wow,
and flutter associated with ancient vinyl technology as "more
authentic".
Pops and ticks are often a sign of an unstable
phono stage with poor overload margins and in that regard, price has
nothing to do with it. People often confuse ticks and pops with the
media. But when an LP is produced, the producer has to sign off on the
test pressing, and one of the things they sign off on is the noise floor
of the LP including ticks and pops. I have plenty of LPs at home that
play the entire side without a problem- and I played some of those at
the recent AXPONA show as a demo of how important phono preamp stability
is. Speed variation is really a thing of the past- no machine made
today or anytime in the last 30 years has audible wow and flutter unless
malfunctioning.
I run a studio and an LP mastering facility;
LPs are usually uncompressed with regard to the digital release files
(this is because the industry expects the latter to be played in cars).
We usually have to request the files in a form untreated by DSP other
than normalization. Our cutter head is indeed ancient, being a Westerex
3D; the 1700 mastering amplifiers are cut off at 42KHz, which is the
practical upper FR of almost any LP- not that there is anything up
there, but most people don't realize that the LP has that sort of
bandwidth (and has since the late 1950s). As far as distortion goes- that
mostly occurs in playback, not record and in that regard is highly
variable according to the ability of the arm to actually track the
cartridge correctly, and how stable the phono section actually is. That
distortion is often much lower than cited by those with a myopic digital viewpoint.
It should be telling that Technics has chosen to jump
back into the LP market with 3 'table entries- all of which were seen at
the recent AXPONA. LP titles are far easier to find now and sales are
still on the rise; the market seems to like them despite their being
somehow 'inferior'. Usually when a succeeding
art replaces the prior art, the latter is usually consigned to the dust
bins of history and the occasional collector. But the LP isn't doing
that- all the pressing houses in the US are busy and often backed up 6
months. 1992, 26 years ago, was the year of least vinyl production.
@cj1965 You complained in an earlier thread about constantly going over the same ole subject matter and how it should be or is handled.... You might want to take a look at MANY older threads. This has all already been covered.
“... Which serves to illustrate, IMO, that when it comes to many of the more controversial things in audio the truth is usually a good deal more nuanced than viewpoints that tend to be expressed by those at or near both extremes of the belief spectrum, and usually lies somewhere in between.”
>>>Oh, my, what’s this, a compromise! An olive branch? Why would anyone call these things controversial? Except for an extremely small percentage, the results of these“controversial” tweaks are all positive. Calling them controversial appears to be nothing more than a ploy or wishful thinking on the part of long term deniers - the most vociferous most of whom never even tried the device under scrutiny. Give me a break! Are they trying perhaps to justify all the backslapping and cutting & pasting of their wild “scientific” theories they’ve been circulating for years trying to get some traction? Do the math.
No controversial audiophile tweak has ever been proven to be a hoax or a fraud. - old audiophile axiom
My opinion on the "failings" of yester-decade's gear is if those characteristics were desirable, why isn't anybody listening to wax cylinders on hand cranked phonographs? After all, the motorized, tube amplified, voice coil driven sound of the 30's was an evolution of that.
@timlub Nobody is building class A amps without measuring some voltage and current at the very least. I'm not designing circuits over here. Most of the heavy measuring has already been done. If I get my voltages and currents somewhere on the range of where the circuit has been measured at, there's good reason to believe that I'm achieving results consistent with those measurements. The hardest thing I've had to do is learn to listen for what distortion is. That has brought me into strong agreement with the belief that dynamics are closely associated with distortion. It took me a while to figure out I should just put the damn meter down and listen, twist pots, listen more, twist more pots, and just get it right. I'm very eager to measure what I'm listening to. I feel I've achieved good results trying to tune two channels by ear and I'm curious to see what those numbers really look like. Not that I'd change it. The sound is smooth, articulate, wide, tall, deep, and well centered. It's the best amp I've ever heard.
@geoffkait There mere fact that these snake oil tweaks get nothing but gloating adoration and no criticism for the results by those who try them strongly suggests that it's a psychological phenomenon, not an objective phenomenon. Since you're so fond of wrongly citing rational arguments as "logical fallacy", I'll point out your very real logical fallacy.
Excellent points... I am learning amp design very slowly. My old buddy is designing a couple of Pure Class A amps now, and he is no different.... He actually forms complete circuit layout in his head before he lays it down on paper... Then he builds, then he listens, then he changes, then he listens. When he gets it right, he'll etch his own boards. These days he is convinced that micro circuitry will sound best. Unfortunate for me, this is over my head. I can follow a schematic, but I don't have the knowledge to lay one out. The most that I can do is to make a few parts changes when finished understanding that one cap or resistor sounds differently than another.
My opinion on the "failings" of yester-decade's gear is if those
characteristics were desirable, why isn't anybody listening to wax
cylinders on hand cranked phonographs? After all, the motorized, tube
amplified, voice coil driven sound of the 30's was an evolution of that.
While that is true, its a simple fact that no-one is listening to 30's technology around here. The list of improvements is much to long to list here- and I'm sure you are aware of them.
...The hardest thing I've had to do is learn to
listen for what distortion is. That has brought me into strong agreement
with the belief that dynamics are closely associated with distortion.
+1
IMO/IME, about 95% of the time when audiophiles use the word 'dynamics' they are really talking about distortion and that word can be safely substituted into the conversation without changing its meaning.
The reason this is so is because the ear uses the higher ordered harmonics to sense sound pressure (GE demonstrated this in the 1960s but little was done with that research). This is probably due to the fact that pure sine wave tones don't exist in nature.
Its right at this point that our philosophies about how to get good sound probably differ; I am of the opinion that since our ears are so sensitive to these harmonics that its not a good idea to do anything design-wise to generate them and so specifically avoid doing that in our designs. This means that I don't use feedback because feedback, while suppressing distortion, also adds some of its own, and all of higher ordered harmonics which can be easily heard. So if I can do a design that does not make those harmonics, it will be smoother and not sound 'loud'.
I've been accused of using 'antiquated' technology in this regard and that is true, but SITs were a short-lived technology in the 1970s and there were no small signal and driver devices that were SITs- only outputs. Regular transistors just don't have the linearity **and** soft clipping to do the job. That is why tubes are still around BTW; if really inferior (and not just antiquated) they would have been gone long ago.
@atmasphere "Each 2150 uses global feedback (proudly: its manufacturer suggests that manufacturers who don't use feedback simply don't know how to do so properly)" About the Boulder 2150 from Stereophile. Different strokes for different folks.
I've heard noise about SITs coming back a bit on account of them being more efficient at converting and inverting AC and DC back and forth. Who knows.
"Each 2150 uses global feedback (proudly: its manufacturer suggests that manufacturers who don't use
feedback simply don't know how to do so properly)" About the Boulder
2150 from Stereophile. Different strokes for different folks.
That isn't quite true- but it is true that many who **do** use it aren't administering it correctly. The problem (known since the 1950s- see Norman Crowhurst) is that feedback makes distortion of its own thru bifurcation of the signal- and so adds higher ordered harmonics and intermodulations interpreted by the ear as brightness and harshness. And no-one has sorted out yet how to get an amplifier to clip graciously while using it. Here is an excellent article regarding the application of feedback and its pitfalls, several of which don't get addressed in many modern designs (and its not an 'anti-feedback' article):
I've got a SIT amplifier right now (and not just a Sony VFET either). It is one of the best solid state amps I've heard. Its too bad this technology got binned before it really was understood.
Anonymity in cyberspace is the breeding ground for all sorts of bad behavior including bullying and brow-beating. Some forums and forum moderators run a tight ship; others not so much. Methinks the governing thought is that we are all adults and should behave accordingly. That doesn't seem to work out so well does it? As someone mentioned, it is the nature of the beast.
Whether it is high-end audio, sports, hobbies, automobiles or your favorite food, everyone is entitled to their opinion - but one must understand and recognize that it is "their opinion" --whether it is based in fact or not. We come from different cultural and educational backgrounds. We all have something positive and constructive to contribute.
Maybe a few ground rules are in order (as long as they are observed and enforced):
It's important to remain civil and respectful. Agree to disagree.
Think before responding
Stay on point
Attack the problem - not the person
Educate not intimidate
Share. Enlighten. Have an open mind. But most of all, have fun.
I assume the discussion is concerning global negative feedback and not local feedback. My amps as well as several other major brands of tube amps use negative global feedback. VAC, one of my favorite major brands, states that their amps use 6 db of negative global feedback. The finest audio/music system I’ve heard is the VAC/Von Schweikert $1million system. I suppose Kevin could have built the amps with no or less feedback, but his design works great with it.
My amps have four variable points of negative feedback which I use the minimum for most recordings (some bad rock CDs need more feedback to make them listenable for my wife). I’ve tried no feedback amps and am dissatisfied with their sound (they were also Class A type).
Negative feedback is certainly a subject that generated plenty of heated debate. The one thing I don't think anyone can argue about is the importance of optimizing the topoly to behave decently before attempting to correct it's bad behavior. I think that's where the solid state crowd can learn from the tube crowd. Tube guys are obsessed with tuning a circuit to get good behavior from the gain devices because gain in their world is too scarce and too expensive to be throwing away on gobs of feedback.
To add a data point to Steve’s (Fleschler’s) input, my 300B-based class A biased VAC Renaissance 70/70 MkIII amplifier provides a choice of 6 different feedback settings, ranging from 0 (no feedback) to 7.5 db. All of those choices represent relatively modest amounts of feedback, even for a tube amp (for example ARC amps commonly have feedback in the area of 10 to 14 db or so), but nevertheless I prefer the 0 db setting. I suspect one reason for that is that my speakers (Daedalus Ulysses) have an exceptionally flat impedance curve. Presumably that tends to lessen their sensitivity to differences in amplifier output impedance, which in turn will vary among the different feedback settings, and will be highest at the 0 db setting. I’d imagine that with a lot of other speakers one of the other feedback choices would be preferable, depending on how the impedance of the speaker varies over the frequency range, and also on how much bass damping it requires (damping factor being inversely proportional to output impedance).
Thanks Al, I didn't know that older VAC amps have variable feedback.
My 125 watt Class A/B tube amps also have variable global negative feedback at reportedly 4,6,8 and 10 db. My similarly high efficiency speakers, unlike yours, have a difficult impedance curve with low impedance in the bass (3.2 ohms). I set my feedback to 4 db, or minimum. Until I improved my system with the SR fuses and Total Contact, I used to set it to 6 db for CDs and 4 db for LPs and 78s. Now everything sounds open and tonally firm at 4 db.
If I were to replace my amps, I would probably buy the VAC 200IQ.
kosst_amojan @geoffkait Please, Geoff, enlighten the unwashed masses here as to what this "sufficiently advanced technology" is that appears to us as voodoo.
Oh, I dunno, costco, but I suspect in your case it could be just about anything that looks at you a little cross-eyed. 🙄
Pop quiz. Multiple choice. Oh boy, oh boy!
Which of the following are not woo?
a. Green Pen b. Mpingo disc c. Silver Rainbow Foil d. Tice Clock e. Intelligent Chip f. Demagnetizing CDs
Wow... Ya got me there. School us, oh great and wise Geoff. Show us the errors of our measurement ways! Open our eyes to the 7th dimension and allow us to gaze upon your majestic madness!
Why measure and count when you can simply BELIEVE. And of course, you're probably forgetting all about the "new math" where 69 db of dynamic range is actually higher than 110, and 2% harmonic distortion is actually less than .02 %.
Hey buddy....get with the program. Vinyl and tube amps are actually better than digital and solid state. Didn't you know? They cost a lot more too so there's your "proof"....
Wow.....Geoff is silent for more than 4 hours, is that a record? .Did I say something to offend him? I certainly wouldn’t want to "hurt his feelings". We all have "feelings" that need to be respected and protected in "safe spaces"....not the "padded cell" safe spaces mind you, just the soft cozy safe spaces where folks can be free to "express their feelings" without anyone being skeptical or passing judgment.
Why measure and count when you can simply BELIEVE.
Unfortunately, the article linked is a source of misinformation. The reason is the article lacks a listing of the equipment used. The most we get is a photo of a 70s machine, which maybe might be the same as the 'first class deck' mentioned (one wonders why this obvious omission was made- was he embarrassed by his playback apparatus?); no mention whatsoever of the phono equalizer(!), all of which have an enormous effect on the results, yet the results are construed to seem as if they apply to all LPs and LP reproducers when such obviously can't be the case.
Wouldn't you want to know what is possible, rather than the results of 1960s tech? Here is an example of what I mean:
The standardised groove geometry on an LP record is
of a 2 thou* groove on a 5 thou spacing (the latter being based on 200
grooves per inch). As the diagram right illustrates, the absolute
maximum modulation of a groove is ±1.5 thou which is equivalent to 76μm
pk-pk modulation.
The above statement is false- LP reproduction has advanced since the early 60s when this statement was more truthful. Cartridges of the period were horrific and variable groove spacing only arrived in the 1970s (and of course, without variable groove spacing you could simply set the lathe for less than 200 grooves per inch... sheesh!). We use 2 mil modulation as 0VU reference as we are conservative- our 'antiquated' 1980s Technics SL1200 equipped with a lowly Grado Gold (which we use to make sure that a cut we are working on will be playable by the garden variety machine) can manage 3db more than that without complaint; the upper limit is obviously higher than described in the above quote and that's with cheaper gear. Newer arms without engineering bugs like the Techincs arm can do even better.
On the flip side (if you will pardon the expression) it turns out that much of the noise floor in LPs has to do with the pressings, not the lacquers, of which the latter have noise floors that are easily in the high -80s or low -90s (since the phono reproducer itself is actually the noise floor if the cutter head and stylus temperature are optimally set). At least one pressing house (QRP, associated with Acoustic Sounds in Salinas, KS) has found that by eliminating vibration in their pressing machines during cooling, the noise floor of the LP surface is dramatically reduced, approaching that of the lacquer. None of the test recordings for this article were made on such pressing machines, as QRP has only had them working in the last 5 years or so.
I think that getting good measurements is great, but this article is an example of Bad Science- IOW fake news.
Let us all celebrate the 1 year anniversary of the kosst, joining us here. It has been such a pleasure for me enjoying his nonsense, in him not trusting his ears, nor him not believing ours. MrD.
@cj1965 Its pretty obvious here who's doing the hand waving. You
can't back up your statements with either measurements or math. You
committed some pretty obvious errors in your math on another thread in
this section; maybe you might consider owning up to that- it would
improve your credibility if you could admit your mistakes.
So far no name calling, ideas and feeling we’re expressed, no heated conversation yet, I have not check this thread for quite a while, because of Axpona 2018, I attended for three days met some members here , told yah, they are much cooler in person...I would just like to add that, sometimes we don’t hear things the way they are. But we hear things the way we are, isn’t it? Ahah..I like to hear things the way they are....Yes we can get along....😀
Those who may be interested in some background underlying the exchanges above between Ralph (Atmasphere) and CJ1965 will find the following thread to be relevant, beginning with the post by Atmasphere on 4-17-2018 and continuing to the end of the thread:
You see, sir, that's how science works - full disclosure of the details.
Hm. Something that article certainly lacked! Based on what you say here, you don't think a little disclosure would have been a good idea? That certainly **seems** what you are saying; if anything, this should have been an objection that you raised about this article rather than stand behind it. Why the contradiction? Are you needing to make others wrong so much that you are willing to contradict yourself? This slight on your part is a bit of hand waving.
As for your other claims regarding what I've posted elsewhere, they don't even merit a response.
Hm. You made the claim that when you cut the voltage applied to a speaker in half, its a 3db reduction. Here's the math:
2.83 volts is 1 watt into 8 ohms. I hope we can agree on that...
So 1/2 of 2.83 volts is 1.415 volts. Using Ohm's Law, to calculate current we divide 1.415 with 8 ohms and we get 0.178975amps.
Power is equal to amps x current, now we know the current so:
0.178975amps x 1.415volts = 0.25 watts. That's a 6 db reduction, not 3 db.
Do you still think it does not merit a response, like- 'oh, I meant 'power' not voltage'? You were being pretty specific about voltage on that thread; perhaps you could clear that up.
Looks like we're seeing that cult of anti-intellectualism rearing it's ugly head here. I can't believe I'm reading somebody lecture a legit engineer on why he should ignore blatant failures of reason. It doesn't get more obvious than that.
You’re using the wrong formula - equating electrical power to sound power. The db formula for sound power is :
10 X log 10 (P/Po) db
where P is the measured sound power and Po is the reference level.
If you doubt me, look it up. I believe it’s spelled out pretty clearly in Wikipedia.
And sound power is a function of the force applied, (in this case the voltage) along with the area and displacement over which that force is applied. When you halve the force and double the area, you wind up with roughly the same sound power that you began with. But improved acoustical coupling with increased area improves net efficiency (electrical power in versus sound power out).
You’re using the wrong formula - equating electrical power to sound power. The db formula for sound power is :
I was using the right formula as I was referring to amplifier power, not sound pressure and was pretty clear about that.
When you halve the force and double the area, you wind up with roughly
the same sound power that you began with. But improved acoustical
coupling with increased area improves net efficiency (electrical power
in versus sound power out).
Again, halving the **voltage** reduces the force to 1/4th.
" Again, halving the **voltage** reduces the force to 1/4th. " - atmasphere
Really? Are you serious? What do you think voltage is, my friend? Voltage is "electro motive FORCE". Halving the voltage does not reduce the force to 1/4. It reduces power to 1/4 since the formula for power expressed simply with voltage and resistance is:
V squared divided by resistance.
Look, I didn’t come here to give lectures on Electrical Theory Basics. This is getting embarrassing. Please review your textbooks. I can’t continue to carry on a technical conversation with you if you fail to grasp the basics.
When is a force not a force? When it’s a voltage. Electromotive force is not (rpt not) a force, as fate would have it. Otherwise, Volts would have units of pounds or kilos or grams or whatever. It’s not the voltage that throws you across the room. It’s the amps, baby,!
Really? Are you serious? What do you think voltage is, my friend?
Voltage is "electro motive FORCE". Halving the voltage does not reduce
the force to 1/4. It reduces power to 1/4 since the formula for power
expressed simply with voltage and resistance is:
The problem here is that voltage does not exist without current. The two together are power. Even though we refer to speakers as 'voltage driven' that is a bit of a charged term (referring to the fact that many amplifiers are designed to act as 'voltage sources' and many speakers are designed to expect a voltage source to be driving it); but in fact power is actually making the speaker move. If you can somehow make a speaker move with voltage but *without* current, you will have a new branch of physics :)
A 3db reduction is halving amplifier power, which is what drives a loudspeaker. Its the 'force' that makes a speaker move and because of that if you reduce the voltage by half, the power to move the speaker is reduced to 1/4 of previous.
I believe that the references to force in this discussion are unnecessary and are contributing to confusion, and I believe that Atmasphere is correct. A short while ago I posted as follows in the other thread I referenced above, in relation to this matter:
Almarg 4-20-2018 Assuming that a speaker is operating in a reasonably linear manner, meaning for example that it is not being over-driven to the point that thermal compression becomes significant, it seems to me that the relation between acoustic power out and electrical power in will remain constant to a close approximation. And electrical power in will be proportional to the square of the applied voltage.
Therefore it would seem to me (and I believe also to Erik, Atmasphere, and Kijanki) that since a 50% reduction in applied voltage will result in a 75% reduction in electrical power in, which corresponds to a 6 db reduction in electrical power in, the result will be a 6 db reduction in acoustic power out.
My comment was seconded in that thread by Erik_Squires, who is particularly knowledgeable and experienced in speaker design. An excerpt from his post:
Erik_Squires 4-20-2018
... the SPL at a reference distance, measured in dB, changes
in proportion to the power OR voltage when either is expressed as dB
assuming there is no compression in the driver.
I believe that the references to force in this discussion are unnecessary and are contributing to confusion, and I believe that Atmasphere is correct. A short while ago I posted as follows in the other thread I referenced above, in relation to this matter: - almarg
Look up the formula for sound power. It is defined by a force exerted over an area and assigned a vector (dot product). The formula for electrical power consumed is entirely different and far simpler - based on measured voltage and current. Understanding the distinction between the two is what provides the necessary insight to explain why efficiency is increased when voltage is DIVIDED (series) among loudspeaker drivers and remains unchanged when SPREAD (parallel) across the same driver. This is trivial first year electrical engineering subject matter. I can’t help the fact that you don’t understand it - regardless of your so called "credentials", "qualifications", or number of posts on Audiogon. To pay adequate deference to the people who developed this body of knowledge, you have to pay attention to things like units. Mixing and matching units in these equations results in obvious error. Again, the formula for sound power is readily available on Wikipedia for all to see. It involves applied force and area which dramatically alters the net resulting analysis. Electrical power input is totally separate and distinct and you cannot ASSUME the two are equivalent. There’s a reason the graph shown in the web page for db conversion that Erik linked to has a value of -6db for voltage gain/loss and -3db for sound power. One look at the two formulae for sound power and electrical power will explain why if you care to devote the time to examine them closely. And with that, I’m done attempting to set the record straight. All I get are insults for my trouble. No good deed ever goes unpunished.
CJ1965 4-20-2018
There’s a reason the graph shown in the web page for db conversion that
Erik linked to has a value of -6db for voltage gain/loss and -3db for
sound power. One look at the two formulae for sound power and electrical
power will explain why if you care to devote the time to examine them
closely.
I'm not sure what you are referring to. The only graph on the page addressing db conversion that Erik linked to is this one, and it just deals with voltage, not power.
In any event, if (as it appears) you are saying that a 6 db reduction in electrical power into a speaker results in a 3 db reduction in SPL at a given distance, rather than resulting in a 6 db reduction in SPL at that distance, we'll have to agree to disagree.
Back to the discussion of zero feedback tube amps. I agree that they may sound good with certain speakers. The EAR 890 with 70 watts Class A power nearly oscillate when paired with Legacy Focus speakers with their low and non-linear impedance curve. However, the EAR 890 sounded just fine on the Legacy Signature IIIs which have a smoother curve and 1 ohm higher bass impedance. Same pre-amp and CD sources, wiring and cabling.
Geoff-I demagnetize all CDs prior to play with the Walker Talisman. It's easy and it works for me. The other tweaks I haven't tried or have an interest in.
My comment was seconded in that thread by Erik_Squires, who is particularly knowledgeable and experienced in speaker design.
You are far too kind. I’m not as knowledgeable as many others, and I certainly make my share of public mistakes. I hope that despite this I leave plenty of room for people to enjoy what they enjoy without imposing my own biases.
I’m sure after this endorsement I’ll suffer a relentless series of public mistakes to make up for it. I will say that I often use XSim to double check my math. Speaker building is not my day job and I am far rustier than I used to be on this, so whenever I’m in doubt, I whip up a sample circuit, and pull up the relevant charts to validate my work. I encourage others to do the same, and frankly, if you have speaker building (or even mere speaker wiring) questions, take your questions and XSim schematics over to DIYAudio:
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