Looking these up, the MRF157 only goes to 80MHz. It can't be True Audiophile if it doesn't have flat response to 400MHz.
Bluetooth is best, it goes to 2.4GHz.
Bluetooth is best, it goes to 2.4GHz.
Sorry, it's on my mind right now so any quip to the order of, "Not what I'd spend a half million on" is going straight in my head to "Yeah, a house"
Mea culpa. And Sisyphus isn't done with us in terms of rolling that current drive rock up the hill yet again
As long as we can reduce the distortion of commercial drivers with current drive, then it has it's place. The remaining question is how do we make the EQ easy?
Hi Jan, not much that I actually disagree with you. But again, may I iterate that I have other objectives in mind that are difficult in getting consideration here. If it had not been for Bill's reference to Purifi, nobody would have heard from me. In fact I have a bulk order of drivers from Purifi on order.
This is one of the best quotes I have heard:
"We don't so much hear distortion levels as distortion mechanisms."
The latter is what I have in mind, no matter what the current [no pun intended] status quo, which can change, but always with some difficulty.
I do know one thing, my general avoidance of using mathematical language that can sound like you know what you are talking about; I do generally but not exclusively avoid that. But you would be correct in saying that maths matter hugely, but they can also be used to put up barriers.
Often to start a conversation you have to start with establishing common ground, start with the familiar, then you build your argumentation on that foundation. This is the method I was taught and face-to-face it works very well. But on social media, I have found painfully, that does not work. You build the foundation and wait for a reply, which becomes "nothing new here" which is true, but missing the point. Once confronted thus, progress is impeded.
So let me shortcircuit it for you Jan: I am chasing distortion profiles of amplifiers that will pretty much conclude why amplifiers sound different?
I will either fail or succeed. I am not a betting man, but I suspect most people will be betting against it. I am Don Quixote tilting at windmills. Well, that suits me just fine. The worst that can happen is failure.
But I do have the right to ask two questions of people here, maybe even three:
1. Do you believe that all amplifiers sound the same?
2. Or are you in the camp that you have heard that amplifiers do sound different. You are convinced!
And if the people in 2. are right, then the third question must me.
3. How do you explain it? Nay, how do you prove it?
So call me Don Quixote, I am trying to find that out.
I do know that Earl Geddes says that the speakers are 90% responsible for what we hear and 10% is the amplifier. But I say that mechanisms would indicate that 10% are is more important than what it may look like superficially.
Also, FM distortions (Doppler, which I have seen mentioned here) are less objectionable that AM distortions. There is a stunning example of this on the Purifi website. That is where I got the mechanism quote from (full exclosure).
Cheers, Joe
PS: I remember on Blowtorch I was told that loudspeakers were not a topic that many there were interested in, so I should go away. Interesting, that seems to have changed? I think the loudspeakers interaction with the amplifier on the current side may finally lead to an answer and that is what I am exploiting: Measurements... and yes, maths too. I have an idea of how to do it. 😉
PPS: I have come up with a variable that I have designated Vre and it has received some acceptable reception. So yes, I do actually do maths. It is related to the proportionality between current, voltage, voice coil heat dissipation, and a correlation with [change of] dB-SPL @ 1M. So there you are...
Last edited:
Diyaudio is big and the black hole does what the black hole wants 🙂 It's the lounge after all.
I think you have made that abundantly clear for many years.
I doubt that very much. The king of word count will be heard!
[unattributed quote elided]
Again, I think we are all in agreement about that, but thanks for telling us about YOU again.
I doubt that anyone but you knows what that means, and I rather doubt that you do as well.
That is the heart of it, isn't it Joe? Your extremely poor written communications skills make it almost impossible to converse in forums like this. You believe that for some reason, if you say what you mean, people will not understand you. You choose instead to say something other than what you mean, then act surprised when people either disagree with you, or have no idea what you are talking about. When they challenge your statements you either claim that you didn't say what you said, or didn't mean what you wrote, or were misunderstood, or are under attack. The remarkable thing is that you think you are convincing face-to-face. If you really open conversations the way you do here, then I suspect people agree with you in the vain hope that you will stop talking.
Wow! That is the first new thing you have said here in a long time, and is pretty much the opposite of everything you have written here so far! This is exciting, and I am sure we are all keen to hear about your findings.
True.
I don't care about that
Thanks for letting us know, but I don't know what you are talking about.
No, you are not.
More gibberish. I look forward to hearing something meaningful.
Last edited:
And I am supposedly the wordy one? Why should I reply when there is no substance? Gibberish indeed!
At least you could be honest and answer the question? Is it 1. or 2. and why the objection to exclose?
Anyway, not my problem.
At least you could be honest and answer the question? Is it 1. or 2. and why the objection to exclose?
Anyway, not my problem.
Last edited:
Are personal attacks like this OK? Or are the rules more lax in the Lounge? Asking questions about the rules should not be a problem as it is a request only.
OK. Thank you. And I agree with you on the first two. And fair enough on 3. and yet the question remains unanswered.
I wonder if there are others here willing to disclose?
What if it turns out that amplifiers that are transformer-coupled have lower critical distortion artifacts that can be measured (but don't look on the voltage side). Think of amplifiers as 'current delivery systems' rather than voltage or current drive perse' (that just obscures the problem). Distorted current must mean less linear force (AM distortion). Pavel's driver measurements have revealed just that, so that is one measurement that is already provided. Seems that current-drive does have some advantages there, often heard as a clearer sounding midrange. Why not make all amplifiers do better?
Maybe tubes really do rule, for reasons yet to be fully revealed?
Good luck and godspeed Joe and perhaps you should also take the phase of the harmonics into consideration.
Below is a quote from art_h2.pdf I found interesting about probable correlation on phase of the 2nd harmonic dominant distortion residual to perceived sound for some people.
Nelson Pass said:
I think most GOOD amplifiers do sound the same. It's the BAD ones you must avoid. 😀
Rotel have used this Class AB circuit for years, still do AFAIK:
Power amplifier classes - Wikipedia
Good design. But slight weaknesses on Common-Mode distortion, and Crossover distortion. To reduce Common Mode, the + and - long-tailed pair inputs should be balanced. That is trickier than it looks.
Have I got to read all 70 pages? A Child of Ten can see the importance of setting the bias correctly! Mine had wandered low. That is what I was up to. 😀
I am convinced that amplifiers can and sometimes do sound different, some glaringly so. I would go so far to say that any two different amplifiers generally have measurable differences in their audio reproduction.
The real interesting (for me at least) question is, at which point do those differences get small enough so that they become inaudible.
Unfortunately, a representative investigation, with many different and characterized amps, droves of listeners tested multi-blind to make it scientifically acceptable, is so prohibitively expensive and time consuming that it won't happen. Especially since you can't monetize the results.
So we muddle on, using our intellectual and reasoning abilities to weed out the most glaring BS.
Jan
Last edited:
Thanks. I might have put my head on the chopping block. But I have an idea and it's something that hasn't been done before. But maybe I will hit jackpot? If I don't, I'll be quiet as a mouse. 😀
Actually, this is not where I am looking. If I say too much here it will just get ridiculed, but this is about using a less than perfect speaker trip up the amplifier in a certain way and actually make the amplifier the DUT. But don't look on the voltage side, OK? Wink, wink, nudge, nudge, say no more!
I am looking for something measurable, in a way I don't think anybody has done/tried before. At the centre lies that Vre variable and based on what I have been able to post earlier on Blowtorch, in fact three times. Then Scott Wurcer asked a question that indicated to some extent that he understood it. The incredible thing is that I could use SoundEasy to find a direct correlation that the force factor that we end up listening to was directly related to current even when there were changes there and not on the voltage side. To an extent, the blogs on the Purifi confirmed that (I am pretty sure I know who wrote it even though no name was mentioned and I think you would too - his first name is early in the alphabet). I already have some measurements that work one way, but instead of making the speaker the DUT, reverse it and make the amplifier the DUT, and then another, and then another, and then a tube amp (transformer-coupled). If there are differences there, then something is really going on and that then needs analysing. I am thinking of measuring amplifiers as current delivery systems, because no matter what amp you use, the force factor is current. And I am not the only one saying it now. Whew! It's recorded on Blowtorch.
In other words, in the too-hard basket. But maybe if a totally different tack was taken... I think I am partly there and maybe it might just work out. What's the big deal if I fail, everybody else has. 🙄
Edit. PS: I already know that a current source amp will look completely different than regular amps with this test. It's how other amplifiers might look different from each other.
Last edited: