I have a 1984 magazine which I refer back to now and again to remind myself how far and yet nowhere we have come in hobby audio electronics. In that is an interesting JLH paper where he discusses DS and his slide into ultra objectivism. Given what was happening in audio journalism at the time you can appreciate Doug's view. IMO any 'view' he has is based on both Engineering and experience (A lot of his designs out there) but 30 years of people not listening and you can see why he seems grumpy.
You have to keep things in perspective. While I respect both DS and RC immensely, I draw the line when authorities dismiss 'balanced designs' 'current feedback' and 'mosfet output stages' on the basis that there is no engineering justification.
There is no engineering justification for an Airbus A380, a Porche or any car that produce more than 100 BHP etc etc. you see where this is going? I am a pragmatist and that the best place to be as an audio guy. You can harpoon the bjectivists and the subjectivist with impunity and still come out smelling of roses.
There is no engineering justification for an Airbus A380, a Porche or any car that produce more than 100 BHP etc etc. you see where this is going? I am a pragmatist and that the best place to be as an audio guy. You can harpoon the bjectivists and the subjectivist with impunity and still come out smelling of roses.
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mixed up example there. The justification for the A380 was economic. As there was a business case for a frickin enormous plane the engineers were set to work.
Ref Porsche (and by extension CFA power amps) the justification is that people will pay good money for that pointless stuff. And if you start amptastic corp and market the slewmagic 400 then bump into DS and say you are doing it cos there are mugs out there who lap up the voodoo he would he dismiss you? Dunno.
But is there any evidence that the CFA designs are superior in anything other than bench drag racing who can wipe out more of the RF band with their HiFi? I've not seen any. Big difference between wanting to build something for the challenge and claiming its better. If we stick to doing things cos they are fun and there is nothing on TV we would kill most of the arguments?
Ref Porsche (and by extension CFA power amps) the justification is that people will pay good money for that pointless stuff. And if you start amptastic corp and market the slewmagic 400 then bump into DS and say you are doing it cos there are mugs out there who lap up the voodoo he would he dismiss you? Dunno.
But is there any evidence that the CFA designs are superior in anything other than bench drag racing who can wipe out more of the RF band with their HiFi? I've not seen any. Big difference between wanting to build something for the challenge and claiming its better. If we stick to doing things cos they are fun and there is nothing on TV we would kill most of the arguments?
You asked about correlation of speaker distortion with listening, and his papers on that particular subject are quite comprehensive and have not, in the intervening years, been refuted.
A very wise fellow once said, "Okay, this is a very unpopular thing to say in hobby audio, but... there’s really not much of a technical challenge anymore to getting an electrical signal from the microphone to the loudspeaker terminals relatively unmolested. I still enjoy designing and building that stuff, but I don’t kid myself that I’m doing anything that’s really advancing the state of the art in audio. I’m doing the equivalent of crossword puzzles or sudoku instead of writing literature or opening new fields in mathematics." Poor sap would never be successful in the high end audio biz.
While they do have engineering justification. The 3 example you took give different results (common mode parasitic rejection, slewrate and stability margin, secondary breakdown)... pros and cons) than other technologies. Now, to prefer them to other is a question of personal experience/preferences or environments, don't you think ?
Not exactly, SY. I was wondering who could, today, print the distortion specifications of an amp with the same numbers than the ones of a speaker...
With other words, if you ask-me what are the threshold distortion numbers for a transparent reproduction, i will answer: "Excuse-me i have an urgent appointment..." ;-)
On the thread "Sound quality VS measurements", the are talking cars and motors...
I seem to recall him saying very similar himself. But he IS doing it for fun and intellectual challenge. He is also a fan of the 'Blameless' architecture. So what is your point?
Edit for clarification: My use of "pointless" there was aimed at the boutique HiFi vendors who are pushing technologies that cannot to any reasonable person give any benefit. Other than Apogee full range owners does anyone need +/-60A peak current requirements etc. I would not cast any aspertions over the DIY work Ostripper is doing and he seems to be having a lot of fun pushing some boundaries as a hobby.
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Experiment by yourself (with designs as close as possible), and you will have an idea of the 'character' difference between CFA and VFA. After that, i beg you will not use the word "pointless" any more.
Same remark about BJT VS Mosfets lateral power devices.
And they are technical arguments i can oppose to BJT for power stages, like secondary breakdown or need of temp compensations. And, there too a difference in character of the reproduction.
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see my clarification. I am afraid to me, if a power amplifier has 'character' something is wrong with it or the listener has a bias. I am however willing to be proved wrong.
As you point out competent amplifiers have a tiny fraction of the distortion of speakers. I am confused as to how 2 amplifiers of a 100ppm or less can have any sort of character. Toole and Geddes and Linkwitz I believe are of similar views.
As you point out competent amplifiers have a tiny fraction of the distortion of speakers. I am confused as to how 2 amplifiers of a 100ppm or less can have any sort of character. Toole and Geddes and Linkwitz I believe are of similar views.
This is exactly what the Geddes metric does.
The SQ vs measurements thread long ago became a waste of time. It's a convenient way of keeping the gas bags in one place so that they don't disturb actual technical discussions, so it is not without its virtues.
Yes I saw that. The miniDSP has a pin strap for a little extra gain. The idea is OK let's just try it and see, I recorded the whole STR130 RIAA test record last night, I'll see what I got. I've worked out all the IIR coefficients for the standard table of historical equalizations (to ~.005dB).
I have noticed the same, and even for MMs where the generator impedance is low. For example Grado Platinum into as low as 2K - and quite a bit better than 47K.
I once did a demo in a shop with various loads on an Ortofon Jublilee MC. Started a 100R, then 47R, then 22R and finally when we hit on 10R there was an noticeable and obvious improvement. Since it has a DCR of 6 Ohm and hence effectively its source impedance, it seems with a number of cartridges benefits getting close to it and that it seems to get to a point where the load starts to "bite" and then perhaps finetune it.
It is definitely electro-dynamic damping we are tweaking.
Cheers, Joe R.
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My vintage Sony super duper TA-E88 has a pair of MC head amps, each having a selectable load resistance of either 40 or 3 ohms. Not stupid, they were.
Jan
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