Ironic how often that this magic word 'magic' is lobbed into discussion by people who profess not to believe in it
If you review that thread impartially you'll notice a blind spot in terms of the power supply details to the signal stages (THAT1200 and LM/OPA). Did you note that Tom originally claimed that the THAT1200 stayed in classA all the time?
No, wrong again - the ingredients would be: "merely adequate power supply", two copies of his amplifier connected to that supply, one of which is being driven hard by a possibly complex signal, which means that the power supply is modulating very badly in voltage and current; and the other copy is fed, say, very low level, high frequency signals in an IMD test.
If you think this is "crazy", consider a recording where in the right channel a bass guitarist is hammering out a frenzied riff, and in the left the drummer is delicately brushing the cymbals, at the same time ...
I don't believe in magic. Frank clearly does.
I read the thread impartially as I only ordered boards 2 weeks ago and noticed you doing your usual rubbish with picking nits everywhere yes. Tom designs ICs for a living. I therefore trust his judgement. Even if some of the internal buffers go into AB at some point there is nothing in the measurements to suggest a detriment to performance. None at all, but a huge benefit (measurable) in having the THAT chip in the circuit.
he published data for the power supplies for those stages. And measurements of the completed board. I don't see what you have to grumble about.
I read the thread impartially as I only ordered boards 2 weeks ago and noticed you doing your usual rubbish with picking nits everywhere yes. Tom designs ICs for a living. I therefore trust his judgement. Even if some of the internal buffers go into AB at some point there is nothing in the measurements to suggest a detriment to performance. None at all, but a huge benefit (measurable) in having the THAT chip in the circuit.
he published data for the power supplies for those stages. And measurements of the completed board. I don't see what you have to grumble about.
Yup you are crazy. If the full power channel has grot 115dB down from the fundamental there is no issue to answer. It's up there in SOTA territory with measurements. You fling components around and claim to have the answer. You are happy, which is good. Shame you troll so much.
So you agree then that he overlooked the detail that his signal stages were not purely classA?
I have looked for that data - link please?
Grumble? Moi?
Hmmm ... I must have bad colours on my TV because ... which one from here, https://yourlogicalfallacyis.com/, is this "argument" ...
You are still missing the point - I want to know whether the nature of the distortion varies when amplifying a subtle signal, when the power supply is unstressed vs. when it is heavily stressed!
Why? Because that is exactly the behaviour I hear in real amplifiers: delicate signal, no stress - everything's fine; delicate signal, another instrument comes in, full bore - a bit of a mess is heard! Some people have never experienced an audio system do this sort of thing correctly, so they can't handle the concept - but doesn't mean it doesn't exist ...
I don't think he overlooked anything. It is not IMO an issue. I'll take an immeasurable 'potential' smidge of x-over distortion for the 90dB CMRR you gain any day.
It was there, you argued with it around post 235. Tom gave numbers you argued semantics. The measurements do not indicate any area where this needs to be improved against established reference points. You clearly think its rubbish due to a class AB buffer deep in an IC and a +/15V regulator that he didn't share the exact design with you for. You are entitled to that opinion, but the end to end performance still stands as superb by any metric for that level of power.I have looked for that data - link please?
Grumble? Moi?
Why? Because that is exactly the behaviour I hear in real amplifiers: delicate signal, no stress - everything's fine; delicate signal, another instrument comes in, full bore - a bit of a mess is heard! Some people have never experienced an audio system do this sort of thing correctly, so they can't handle the concept - but doesn't mean it doesn't exist ...
Try a better amplifer? Or maybe, just maybe do some measurements to find out what is wrong with yours rather than just take pot shots at those who do measure?
So you say he did not overlook anything that he (and you) consider an issue. CMRR is not the issue, crossover distortion is not the issue. More goalpost shifting going on here
Link please?
Numbers (1mohm - 10mohm I seem to recall) were pulled out of a hat. Just the data please - what regulators did he say were being used? I'll examine the DSs myself.
Performance as determined by measurements, undeniably.
Not taking pot shots at anyone, except those who are very close minded; again, I have no arguments with Tom's effort, whatsoever. But if I had one of his units I would do the subjective equivalent of the sort of testing I've just been talking about ...
When I went to the recent audio show most amps I heard failed in this area - easy to hear the symptoms, when you know what to listen for. I was pleasantly impressed by the few which showed good behaviour, and top of the class was the Bryston unit ...
So you say he did not overlook anything that he (and you) consider an issue. CMRR is not the issue, crossover distortion is not the issue. More goalpost shifting going on here
Link please?
Numbers (1mohm - 10mohm I seem to recall) were pulled out of a hat. Just the data please - what regulators did he say were being used? I'll examine the DSs myself.
Performance as determined by measurements, undeniably.
No goalpost shifting. You pulled a ****-arsed theory out the hat that the THAT1200 would limit sound quality due to power supply with nothing to back you up other than your belief system. The bom is published in the thread which you can find in the vendors forum. I am not going to find links for you if you are too lazy to look yourself.
You also have not pointed to anything on the given measurements that shows this sound quality theory of yours in action. Why are you so afraid of data when presented?
In my brief look at the thread I can't seem to find any reference to the fact that it should have been measured with anything but a resistor. Maybe you know better or are you just guessing....? But since you know you may be so kind to guide me..??
Claiming superiority requires superior methods
Claiming superiority requires superior methods
Weeellll ... I am playing with an amp design, discrete, that manages -130dB harmonics at 20kHz, while dumping well over 3kW into 1 ohm. Of course, silly stuff - and assumes everything's perfect, including PS's - but demonstrates what the circuitry can do ... might be a touch more than $150 though, .
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The normal process is that standards are supplanted by improved standards, where there is shown to be a necessity.
Unfortunately no superior and reliable standards of test have been invented, but sustained assaults on the validity of the existing ones are being mounted. None of these have been shown so far to be anything but scientific (or personal) ambitions out of control.
It is said that the test regime will be incomplete until 'dynamic' testing is implemented. OK, go ahead and implement it and show us the results to demonstrate your case, and how it correlates with hearing tests.
Complaining that other people aren't doing it is wearing a bit thin.
Unfortunately no superior and reliable standards of test have been invented, but sustained assaults on the validity of the existing ones are being mounted. None of these have been shown so far to be anything but scientific (or personal) ambitions out of control.
It is said that the test regime will be incomplete until 'dynamic' testing is implemented. OK, go ahead and implement it and show us the results to demonstrate your case, and how it correlates with hearing tests.
Complaining that other people aren't doing it is wearing a bit thin.
The key word there is "necessity" - and the frazzled mess in the current world of audio I would have thought should supply some of the motivation ...
Some people are in better places to do this research, because they have easy access to the right gear - and because their heads are in a clearer space; everyone has history, for various reasons, and sometimes this strongly gets in the way.
Some people are in better places to do this research, because they have easy access to the right gear - and because their heads are in a clearer space; everyone has history, for various reasons, and sometimes this strongly gets in the way.
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