john curl said:
I don't have to:
http://www.diyaudio.com/forums/attachment.php?s=&postid=585586&stamp=1109540374
I see you now appear to accept that an inductor is necessary after all.
I still consider it a minor liability, BUT it is only 0.5uH, AND any output wire has some inductance also.
Some people just don't want to learn something new. I don't understand it, but it does keep other major designers off this thread, since they don't want to waste their time being put down for making small improvement suggestions. Count on it.
Some people just don't want to learn something new. I don't understand it, but it does keep other major designers off this thread, since they don't want to waste their time being put down for making small improvement suggestions. Count on it.
Arguing
I'm amazed about how you guys are not able to take John's standpoint as what it is:
The experience of someone who designed and still designs successful amplifiers. And listened (well, thats the very reason why he and some others are successful, not only numbers, but _listening_).
Maybe even he is not able to explain the effect tecnically. So what? Why trying continuosly to belittle him? Why?
What are you doing in these forums? It's all done right now...low THD is already a nobrainer even for diy, and you, Mikeks, estuart, and others, are all way ahead respect to a mortal diyer. So what, 0.000...% will be an easy task for you. And if it's low THD, sonic differences seem not to exist for you, at least not if the difference is heard only by JC, CH, NP and others. So what? What are you looking for here?
Mikeks, for instance, what have you done in audio apart a paper on output protection? You don't give the impression that you have built and listened to even one amp.
You are arguing all the time that all you need is to measure, and if THD is low enough, then the amp sounds as it should, no coloration.
So what else are you looking for in these forums? It's already well possible to build an amp with 0.00....% THD, no need to look out for new designs. Just build an amp as you say, do some good R-C filtering on the VAS, tons of feedback and Error correction. It's all there.
What are you doing here, other than annoying 80% of the members? Does it make feel you like Galileo? (Your words
)
And a big cheer to the mods, who rather delete posts arbitrarily (hehe Kanwar, you didn't notice it yet, he...?? Do not mention Charles Hansen again, and beware of posting a link to another forum! It will evaporate...) instead of making an end to such an annoying member with an arguing : contributing ratio of around 10'000:1.
Tino
I'm amazed about how you guys are not able to take John's standpoint as what it is:
The experience of someone who designed and still designs successful amplifiers. And listened (well, thats the very reason why he and some others are successful, not only numbers, but _listening_).
Maybe even he is not able to explain the effect tecnically. So what? Why trying continuosly to belittle him? Why?
What are you doing in these forums? It's all done right now...low THD is already a nobrainer even for diy, and you, Mikeks, estuart, and others, are all way ahead respect to a mortal diyer. So what, 0.000...% will be an easy task for you. And if it's low THD, sonic differences seem not to exist for you, at least not if the difference is heard only by JC, CH, NP and others. So what? What are you looking for here?
Mikeks, for instance, what have you done in audio apart a paper on output protection? You don't give the impression that you have built and listened to even one amp.
You are arguing all the time that all you need is to measure, and if THD is low enough, then the amp sounds as it should, no coloration.
So what else are you looking for in these forums? It's already well possible to build an amp with 0.00....% THD, no need to look out for new designs. Just build an amp as you say, do some good R-C filtering on the VAS, tons of feedback and Error correction. It's all there.
What are you doing here, other than annoying 80% of the members? Does it make feel you like Galileo? (Your words
) And a big cheer to the mods, who rather delete posts arbitrarily (hehe Kanwar, you didn't notice it yet, he...?? Do not mention Charles Hansen again, and beware of posting a link to another forum! It will evaporate...) instead of making an end to such an annoying member with an arguing : contributing ratio of around 10'000:1.
Tino
I was trying to avoid using coils on the output of all Creek amps I've designed. The only exception was 5350 where I've used about 0.5uH on the output. All amps were stable with a pure capacitive load up to 2uF directly on the output terminals and more if there was a short lengh of wire in series with the cap. I would rather agree with John that it is better to avoid using an output coil if possible for the sound quality reason.
Alex
Alex
anli said:
I think the only thing I am quite sure of is that from purely sound quality point of view a good coil is no coil at all
. However it is nesessary to use it sometimes and for different reasons (stability into capacitive loads, o/p stage doesn't like RF injected into it, or to limit a short-circuit current rise speed to give protection enough time to deal with it as in Kanwar's amps) . It makes sense to build a coil if required with least distortion and other unpleasant qualities, like DC impedance etc.Alex
The lower the global feedback, the smaller the output inductance required to isolate the feedback loop from any capacitance at the output.
Thus, it is hardly surprising that JC, who advocates little or no feedback (but has never adduced evidence for this position), can get away with not using any coils in his amps.
Thus, it is hardly surprising that JC, who advocates little or no feedback (but has never adduced evidence for this position), can get away with not using any coils in his amps.
Folks, it defies common sense to suggest that a load-isolating inductor of a few uH impairs "sound quality" when connected in series with a loudspeaker system containing a passive crossover network with inductors of values in the hundreds of uH.
It is for this reason that members are urged to THINK for themselves, and not to abdicate reason on the alter of so-called "Gurus".
It is for this reason that members are urged to THINK for themselves, and not to abdicate reason on the alter of so-called "Gurus".
john curl said:
Red herring #3476321
Hi John
A very high damping factor at high frequencies isn’t particularly precious. At 20 kHz, a few micro henries of output coil inductance is a rather small contribution, compared to combined affects of cable, crossover and voice coil impedances.
Also, coil ringing when driving highly capacitive loads isn’t an issue worth sweating over if the output network is properly designed with the inductor resistively damped and incorporated into/with a Zobel network.
What were you doing 30 years ago, just dangling a bare inductor behind the speaker binding posts?
john curl said:
Do you sincerely believe that Halcro amps (a single example amongst many, many others) are only good for driving sub woofers? Or are you just making disingenuous, unsubstantiated generalisations?
Cheers,
Glen
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