Maybe one day Joe will publish the evidence he keeps promising, he seems to recognise the fact that his claims need evidence, that is a good sign. Maybe then there will be a proper discussion instead of the game playing.
No, cause i keep an ignore list, but what does that have to do with the rather innocuous and technically (as always) correct remark of PRR (post 185) on the basis of which you proclaimed him as a troll? They are different people and not some enemy team playing against you.
Thanks, my wife is Italian, actually she is Sicilian, so watch out!
My bed is awaiting....
Please don't take anything I said the wrong way and I am sorry if you or anybody else did. Please understand also it is late here and I am just feeling a bit fed up with things right now. I just want people to answer on substance from now on. Trust me, the ones I call the "usual suspects" know who they are, and they are not you. Goodnight, take care.
Being thick-skinned as I've grown over the years, I'll ask for the obvious about the working of a transformer. Passing electrical energy from primary to secondary the transformer drops secondary voltage with rising secondary current. Losses are with thermal energy, copper and iron 'resistance'. But what about the reluctance of two coupled coils, both opposing current change? Is the answer simply the energy in the electromagnetical field changes with changing power consumption at the secondary?
I see there's another fellow (from Finland) who's website appears to strongly support the current drive point of view - Frontpage | Current-Drive - The Natural Way of Loudspeaker Operation Lots of reading on the subject there, if anyone would like! Apparently, others in the audio world (besides Joe) are pursuing this.
@dave - you lost me when you said these T/S parameters are not always measured using a low Z signal source and that you have several high Z signal sources specifically for the purpose of driver evaluation. As I respect your status as a well seasoned speaker system designer, please explain.
My confusion comes from an engineering perspective, which favors standards from which data is derived. So when someone says a very low Z amplifier is a requirement for these measures, that to me is similar to saying a pulse generator should have a 50 ohm output. Obviously, most manufacturers of test gear agree and that's how it's done. Then someone comes along and says I use a pulse generator with 10K output for my RF measurements. That's when I get lost. What use could that possibly be? Why not just use the standard way of measuring?
If this is part of your "secret sauce" that results in a speaker system designed "from the beginning" more suitable (and more consistent) to use with amplifiers of higher Z outputs, then I have something to get a grip on. However I would still think measurement from the standard, then allow the software program to transform the result into new values by entering in the amplifier output impedance. Assuming of course that the software was programmed correctly to do this.
Thanks!
@dave - you lost me when you said these T/S parameters are not always measured using a low Z signal source and that you have several high Z signal sources specifically for the purpose of driver evaluation. As I respect your status as a well seasoned speaker system designer, please explain.
My confusion comes from an engineering perspective, which favors standards from which data is derived. So when someone says a very low Z amplifier is a requirement for these measures, that to me is similar to saying a pulse generator should have a 50 ohm output. Obviously, most manufacturers of test gear agree and that's how it's done. Then someone comes along and says I use a pulse generator with 10K output for my RF measurements. That's when I get lost. What use could that possibly be? Why not just use the standard way of measuring?
If this is part of your "secret sauce" that results in a speaker system designed "from the beginning" more suitable (and more consistent) to use with amplifiers of higher Z outputs, then I have something to get a grip on. However I would still think measurement from the standard, then allow the software program to transform the result into new values by entering in the amplifier output impedance. Assuming of course that the software was programmed correctly to do this.
Thanks!
From the above quoted website:
"(Note: Like in the book, existing faults are brought out at times even quite vigorously. However, the issues treated are universal, and nobody has reason to take them personally although recognizing one's own misconceptions may sometimes produce inconvenience. Yet of course there are always those who do, reacting with personal smear instead of technical facts. Examples can be found on Diyaudio.com. There is nothing surprising; it has always been so. That's also why Copernicus postponed the publication of his work De revolutionibus orbium coelestium until the last days of his life.)"
Awwwwwwe... So too bad. Must be a "touchy" subject, this "current drive" and why tubes have an identifiable sound.
"(Note: Like in the book, existing faults are brought out at times even quite vigorously. However, the issues treated are universal, and nobody has reason to take them personally although recognizing one's own misconceptions may sometimes produce inconvenience. Yet of course there are always those who do, reacting with personal smear instead of technical facts. Examples can be found on Diyaudio.com. There is nothing surprising; it has always been so. That's also why Copernicus postponed the publication of his work De revolutionibus orbium coelestium until the last days of his life.)"
Awwwwwwe... So too bad. Must be a "touchy" subject, this "current drive" and why tubes have an identifiable sound.
There is nothing so new above, transconductance amplifiers have existed for years, and chipsets to do it for many decades.
The Finnish guy DID state very clearly current drive DOES NOT WORK for low frequency drivers (where guess where is 90% of the energy).
Having just heard a system which claimed this novelty (again) but integrated the whole lot into a SINGLE cable driven loudspeaker system, I can honestly say it can sound pretty foul too, when wrongly implemented.
As for valve amplifiers sounding different.
They sure do,
They remove all the nastiness and harshness created by stuff made with sand, ESPECIALLY the stuff consisting of 1s and 0s switching the things on and off zillions of times per second.
If there was a good reason for recreating valve amplifiers, it was to cope with massive overloads in microphones, then cope with the horrible digital harshness introduced all along the line from there on...especially as it re-emerges sort of re-constructed from the DAC.
Joe isn't pursuing current drive per se, he thinks he's found a distortion mechanism by looking at the current supplied by the amplifier.
Anyway, mixed mode feedback has advantages Current Drive
Variable Amplifier Impedance
If there was a good reason for recreating valve amplifiers, it was to cope with massive overloads in microphones, then cope with the horrible digital harshness introduced all along the line from there on...especially as it re-emerges sort of re-constructed from the DAC.
All of those things add up through the chain, for sure, but you forgot the worst one; dynamic range compression. Even in the pure analog days, it was bad - but the digital world made it so much worse. The Loudness War - nobody wins.
If there is one thing I regret about building a "hi-fi" system it is that it has revealed just how terrible some (a lot of) music production is. On the other hand, well-produced/mastered music sounds simply unbelievable - so it is bitter-sweet.
Regarding tubes vs. SS. Both can sound excellent and both can sound terrible. All things being equal, I prefer my specific EL34 P-P amp over the SS options I have, but the only way i can explain it is with the common, detestable "audiophool" words like "presence" and "life". My family hears the same things I do (yet another worn-out cliche).
I've read through this thread and it felt like deja vu - as I am sure it has to many others. We've all been through this, over and over again. In the end, the proof is in the listening. I never get tired of listening to my tube amp but I have certainly tired of some solid state amps.
A SET build is next for me. Parts are on the way. Enjoy the rest of the discussion/argument everyone. In the end, it doesn't matter. We are spoiled for choice so I am going to enjoy it, and I am certainly not going to feel the need to defend my choices.
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@scottjoplin - Didnt Joe R make the LM1875 current mode amp thread? I'd call that pursuit, for lack of a better word.
Really appreciate the two links, as I've been recently interested in mixed mode feedback, i.e. mechanism for variable amplifier output Z and I have the LM1875 chip amp to modify / implement it. Thanks!
Really appreciate the two links, as I've been recently interested in mixed mode feedback, i.e. mechanism for variable amplifier output Z and I have the LM1875 chip amp to modify / implement it. Thanks!
Tubelab SSE might be a good option, mate. That's what I've decided to do. It's only going to cost me about $700 CAD (although I already have most of the tubes, switches and a few of the minor components).
T/S can be measured with both a voltage souce or a current source, but using a current model seems to be the preferred method.
K can’t find Brian Steele’s method of manually measuring a driver, but it uses a large R to make a voltage amp (and it has to have a stiff PS that doesn’t sag) act like a current amp.
I used a simialr circuit with FizzMeasure.
And then S=L WT2 which comes with a dedicated USB in current amp. And it actually uses the same algorithm as Steele outlined, instead of measuring the impedance curve and guessing the patameters as many products do.
dave
Attachments
That is ESA, he has been mentioned before, his book is the currently available resouse on current drive.
Here, i found the thread here:
The Secret of Tube Amplifiers Revealed - and much more!
And here:
NEW: Book on Current-Drive of Loudspeakers Published
And while i was looking for ESA’s (member ETA) thread i found this: Current drive amplifier?
and
Current drive for Loudspeakers
dave
he whole subject of using current drive, drives many, seems in particular those embedded in the mainstream way of thinking, into a state of disbelief.
dave
Not quite. It does not work in most speakers with a significant impedance rise at resonance.
Speakers that work with current amps (or high output impedance amps like SETS) at low frequencies do exist, either the resonace has been squashed either electrically like the Elsinore, or acoustically as with an aperiodic TL. Or the effect of the resonance actuallt. leads to an extention of the bass response (ie a SET on Vulcan with FE206x). Impedance interaction can also benefit the top (FE127e).
It helps if the driver starts with a low Qm (ie resonant peak is lower to start with), but it is not always the case (FE206 has highish Qm).
Back when I was looking into current amplification for speakers what turned me off to the idea was that so many "normal" (read: commercial) speakers have poor damping/control of the impedance peaks from speaker resonance, so I haven't looked into them much in quite a while. I've heard a few setups with them on nicer fullranges that did seem to work very well, however. I might have to drop back into the rabbit hole and start researching them again.
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