really ?voodoo or dreaming, whats the difference 😀
Yes really. You give me an 'inadequate" PT with sufficient voltage and power and I will design and build a power supply with it that puts out clean DC and no mechanical vibration and close to zero EMI and whatever else is required. I didn't say it would be cheap 🙂
Yes it was tongue in cheek but the point was that, like everything else, PTs are not rocket science, you just have to know what you're doing.
any traffo that has sufficient voltage and power is never "inadequate" in my book, that is why i have a hard time to respond.....
MGH's belief system tells him that there are differences in sound in every aspect of amplifier design and build.....that choice of resistors, capacitors, cables and transformers makes a difference....being a non technical person makes him vulnerable to audio vodoos out there....
my belief system is that it is the final outcome that matters....the real challenge to any designer is to come up with a good sounding system using non boutique parts, or meager parts even....
MGH's belief system tells him that there are differences in sound in every aspect of amplifier design and build.....that choice of resistors, capacitors, cables and transformers makes a difference....being a non technical person makes him vulnerable to audio vodoos out there....
my belief system is that it is the final outcome that matters....the real challenge to any designer is to come up with a good sounding system using non boutique parts, or meager parts even....
So you're last statement agrees with my belief system... that choice of component does matter...it is implicit in your statement. However, your assuming I think boutique parts sound better than non boutique parts, which is untrue. Everyone has a belief system..mine is based on empirical evidence making comparisons of different components. Sometimes known physical laws explain what I hear and sometimes not. Not sure what you mean by nontechnical as I am experimental biologist with background in chemistry. I do know how to conduct a proper experiment.
Some physicists have had great success in biology, by applying existing known science to biological systems - for some reason people trained as biologists had not done this. Maybe it is time for a biologist to have great success in physics, by developing new science for physical systems (like audio amplifiers). Or does 'known physical laws' mean just 'known to most biologists' or 'known to science'?MGH said:
hi MGH,
In SE tube amp, filament noise was a problem in high filament voltage tube such as 211. will U considerate use HF (>65Khz) filament power supply for it.
In SE tube amp, filament noise was a problem in high filament voltage tube such as 211. will U considerate use HF (>65Khz) filament power supply for it.
Biology used to be a "soft" science but at least parts of it have come of age in recent years.
In my research area (developmental genetics), good knowledge of physics is more important than any knowledge of "what kind of flower/butterfly is that?".
If you deal with pulsed laser applications for example simple school knowledge does not get you far. And yes, the biologists around me, all (ok, there are exceptions) know how to conduct a proper experiment (starting with a controlled environment).
[Back to original thread topic]
In my research area (developmental genetics), good knowledge of physics is more important than any knowledge of "what kind of flower/butterfly is that?".
If you deal with pulsed laser applications for example simple school knowledge does not get you far. And yes, the biologists around me, all (ok, there are exceptions) know how to conduct a proper experiment (starting with a controlled environment).
[Back to original thread topic]
That is true...but the distinction can be murky. Crick and structure of DNA comes to mind, but he was both physicist and biologist, and his partner was Watson, a biologist.. both Nobel Laureates. I also know well known physicists who absolutely bombed in biology putting forth bad theories that had they had basic understanding of biology would have save them the embarrassment. A biophysicst who made great contribution to our interest is von Bekesy who elucidate the function of the middle and inner ear. He got the Nobel for that. He was originally trained as chemist. Fact is biology encompasses physics, chemistry, psychiatry, etc. There are many biologist who made great contribution science and modern medicine would not be possible without them. Also those involved in development of computed tomography (CT) and magnetic resonance imaging (MRI) important in medicine are biologists, chemists, and physicists. I'm involved in this.
Most biologist want to make a contribution in biology, not physics. Physics is tool for biologist to explore biology. But many pure physicists think they're experts in biology when they clearly are not.
I didn't realize I was submitting a manuscript to a science journal. I thought the context was implied. Let me make myself more clear. Let's say you have two PTs, one made with C-core and the other EI core (or toroid for that matter), whose specs fully meet the demands made by a tube amplifier circuit, and lets assume neither have audible hum. All other factors being equal, would you expect to hear a difference in sound...ie, pick your choice, dynamics, high frequency clarity, bass impact, soundstaging, etc. If all you believe is what matters is what you can measure with an oscillisope, the point is moot. But most of us probably agree that there's more to it than what we currently can measure.
It has been voiced before that different transformer topologies ie Toroidal vs EI vs R core vs C core with the same VA rating will behave differently to mains borne transient noise.
I can't speak for R and C cores but EI transformers are better at blocking mains borne noise than a similar Toroidal transformer.
My 2 x 100W Class A amp runs two 500VA toroidals with CLCC and the result is silky silence. (When it should be of course)
I can't speak for R and C cores but EI transformers are better at blocking mains borne noise than a similar Toroidal transformer.
My 2 x 100W Class A amp runs two 500VA toroidals with CLCC and the result is silky silence. (When it should be of course)
Last edited:
No.MGH said:
Do you literally mean oscilloscope, or are you using this as shorthand for any electrical measurement based on sound physics? I can certainly imagine problems for which a 'scope is an inappropriate tool, but that does not mean they cannot be measured.MGH said:
I might agree that there's more to it than what we currently do measure. I am not aware of any hard evidence of issues which cannot, even in principle, be measured.MGH said:
I would tentatively agree, that perceived differences in sound should be measurable. So, if someone states there was no measurable difference, the measurement was just of the wrong parameter.
In addition, there are perceived differences that cannot be measured because they are not there (also called imagination).
Everything else is Voodoo.
With regard to PT, proper voltage, power rating and internal resistance should be the main point. I just can't see what difference the core material/shape makes, if you do not run the transformer at the edge of core saturation. We are still talking 50/60Hz here, or not? Magnetic stray fields and mechanical buzz are not considered here by me.
Martin
I would add emi rejection as an important parameter to the transformer as well since we are relying on them to function in part as a low pass filter.
One thing to keep in mind with measurements, is that the equipment to do so is continually improving.
For example, most FFTs I've seen from the 60s/70s had a noise floor of -80dB. Today even a computer with a good sound card has a noise floor below -120dB. Harmonics that were not evident previously are easily seen.
I expect the same to be true of most equipment (Oscilloscopes withstanding as they are mostly limited to 8bit resolution and 2% accuracy, with more expensive ones going to 12 bits.)
The second issue is knowing WHAT to measure. Do we really understand everything necessary?
One thing to keep in mind with measurements, is that the equipment to do so is continually improving.
For example, most FFTs I've seen from the 60s/70s had a noise floor of -80dB. Today even a computer with a good sound card has a noise floor below -120dB. Harmonics that were not evident previously are easily seen.
I expect the same to be true of most equipment (Oscilloscopes withstanding as they are mostly limited to 8bit resolution and 2% accuracy, with more expensive ones going to 12 bits.)
The second issue is knowing WHAT to measure. Do we really understand everything necessary?
Good point
No, of course there is still a lot to learn. But our knowledge of sound perception is increasingly growing. If you take that into account at the engineering level, there is little left to worry about.
As an example, if I read construction threads by Wavebourn (just one example, there are plenty of skillful designers here) who takes the dynamic behavior of distortion and IMD into account (which can be measured), I am sure you end up at a "more natural" sounding system.
I agree that the key is knowing what to measure (and why).
Modern biology is in no way a soft science. I deal with nuclear magnetic resonance and X ray imaging of the human body.
Point well taken, I was just trying to point out different technologies involved in making PT. Yes, 50/60 Hz.
Let me give you an example from your field. You have 2 identical twins. You feed one of them lots of tomatoes for a year, otherwise they have identical diets. Would you expect them to look/act different after a year? I.e. clarity of smile, twinkle in the eye, spring in the step, apparent happiness, etc?
Ask 100 laymen and 95 of them will think one or the other person "looks" better. As a professional, if you acted to recommend a diet based on that "evidence" you'd be summarily fired.
The fallacy of your line of thinking is that you confuse purely subjective layman opinions with "empirical evidence". While a professional wine taster's opinion might be considered evidence, the listening opinions of random laymen on a forum is not. For all we know, you may be getting opinions from people who are tone deaf, have no critical listening skills and/or have severe hearing damage. If you want empirical evidence, assemble a group of listeners with tested and known hearing ability.
- Status
- Not open for further replies.