Fred
I know that there are many designs using gate resistors to increase stability.
Could you elaborate more clearly what effect it does cure ?
I ask because it will move the pole, introduced by the driving impedance and the gate capacitance, lower in frequency making dominant pole compensation more difficult (at least from a first glimpse).
Regards
Charles
I know that there are many designs using gate resistors to increase stability.
Could you elaborate more clearly what effect it does cure ?
I ask because it will move the pole, introduced by the driving impedance and the gate capacitance, lower in frequency making dominant pole compensation more difficult (at least from a first glimpse).
Regards
Charles
traderbam said:
No...on both counts......
traderbam said:
No...
traderbam said:
Which people are you enigmatically referring to...?
Have these 'people' presented hard evidence of the irrefutable kind that feedback is enherently bad for your health?
If so, please.....the suspense is unbearable....put your humble serfs out of their misery....Oh maestro.....enlighten your humble servant.
Re: Can I add an additional supplementary question?
Many prototypes....several of the double-pole, double-zero variety by a certain manufacturer in a store near you (since may, 03), as we speak!!
No difference......whatever!
Two-pole: high psrr sustained to higher freqs; low THD+N sustained to higher freqs; lower noise.
ALW said:
Many prototypes....several of the double-pole, double-zero variety by a certain manufacturer in a store near you (since may, 03), as we speak!!
ALW said:
No difference......whatever!
ALW said:
Two-pole: high psrr sustained to higher freqs; low THD+N sustained to higher freqs; lower noise.
ppl said:
Hi ppl,
I agree with almost everything you said.....i am just not sure about the last bit.....perhaps you might assist my understanding by throwing more light on the point?
cheers.
Oh...contrary to your statement, i think pole-spliting is a 'good thing'.......any tendency for the first non-dominant pole to, as you put it' 'bite', can be quelled by converting the system into a low pass shelving amplifier, (below), with the shelving zero used to nominaly cancell the first non-dominant pole.
Your recommended resistor in series with Cf is indeed 'good practice', but has a more pronounced effect on the location of the closed-loop pole, than on the shelving zero, as elementary calculation and simulation should reveal.
Attachments
feedback trends
"Have these 'people' presented hard evidence of the irrefutable kind that feedback is enherently bad for your health?
If so, please.....the suspense is unbearable....put your humble serfs out of their misery....Oh maestro.....enlighten your humble servant."
There are any number of amps on the market that employ must less negative feedback and even some with no loop feedback around the output stage. If one were really in suspense, how hard is it to build an amp and vary the amount of loop feedback and listen to the various permutations. I've done, Jocko has done it, and I have heard the results of a mod for a C-J tube amp that charged the open loop gain about 10%. It was a very real improvement and surprised me how sensitive the sonics were to small differences in the amount of loop feedback used. There are even op amps designed for less open loop gain than the typical 100 to 120dB at DC. I would imagine that AD and Burr Brown had reasons for this that were beyond the "high end hysteria" that some would attribute this trend to.
"Have these 'people' presented hard evidence of the irrefutable kind that feedback is enherently bad for your health?
If so, please.....the suspense is unbearable....put your humble serfs out of their misery....Oh maestro.....enlighten your humble servant."
There are any number of amps on the market that employ must less negative feedback and even some with no loop feedback around the output stage. If one were really in suspense, how hard is it to build an amp and vary the amount of loop feedback and listen to the various permutations. I've done, Jocko has done it, and I have heard the results of a mod for a C-J tube amp that charged the open loop gain about 10%. It was a very real improvement and surprised me how sensitive the sonics were to small differences in the amount of loop feedback used. There are even op amps designed for less open loop gain than the typical 100 to 120dB at DC. I would imagine that AD and Burr Brown had reasons for this that were beyond the "high end hysteria" that some would attribute this trend to.
Re: feedback trends
No Hugh.....i do not 'enjoy' insulting people.......
i just run out of patience with Mr Dieckmann, who confesses on the one hand that he is ignorant of the fact that the first two stages of an amplifier can be run in class-AB.......,
....and then proceedes, without flinching or blushing, to pour scorn on the source, (yours truly!), of his enlightenment on the subject.......ditto....traderbum.
It was for such as he that the word 'stupid' was invented...wouldn't you agree?
if i knew the particulars of the system to which you applied the worthy, and the manner in which it was applied, i would be better placed to opine on your misfortune.
AKSA said:
No Hugh.....i do not 'enjoy' insulting people.......
i just run out of patience with Mr Dieckmann, who confesses on the one hand that he is ignorant of the fact that the first two stages of an amplifier can be run in class-AB.......,
....and then proceedes, without flinching or blushing, to pour scorn on the source, (yours truly!), of his enlightenment on the subject.......ditto....traderbum.
It was for such as he that the word 'stupid' was invented...wouldn't you agree?
AKSA said:
if i knew the particulars of the system to which you applied the worthy, and the manner in which it was applied, i would be better placed to opine on your misfortune.
Re: Re: Can I add an additional supplementary question?
Is it no difference or the later? Are both of these replies in response to measured difference between single pole and double pole amplifiers? Could you clarify want you meant?
Is there some reason that the commercial amps with the double pole double zero you mention are anonymous. Is this a design secret that they don't want in the public domain, an invitation for the curious to try and figure out what manufacturer, or some other reason that remains a mystery to me at present? I would think such a proponent of this approach would be eager to point to an example of its commercial success. Why the big secret?
mikek said:
Is it no difference or the later? Are both of these replies in response to measured difference between single pole and double pole amplifiers? Could you clarify want you meant?
Is there some reason that the commercial amps with the double pole double zero you mention are anonymous. Is this a design secret that they don't want in the public domain, an invitation for the curious to try and figure out what manufacturer, or some other reason that remains a mystery to me at present? I would think such a proponent of this approach would be eager to point to an example of its commercial success. Why the big secret?
fdegrove said:Hi,
Oh, I see...just me cupper...
How much headwind does he want?
Wait a minute..Fred, Jocko + Frank?
Just add Eric and you have yourself a sinbin recipe...
But of course....
Cheers,
Hi fdegrove,
I think 'they' are rapidly learning that yours truly does not suffer fools gladly!!!
cheers.
why all the small i's
"..i am done with Mr. Dieckmann...."
I just tried to ask a few simple questions with no real malice. You would no doubt reply if I was to trade barbs, but everyone is tired of that and if you won't take the time to insult me in Latin anymore, so what fun is it?
I meant to ask if the no difference referred to the sonics and not the measurements. I still don't see what the secret is about which commercial amp(s) uses the double pole double zero topology and am interested, as are others, I would imagine.
Will someone else ask, since I have been boycotted despite my real efforts to drag this out of the mud and up to the level of civil discourse. I will try to be even more sensitive and leave out anything that could be misconstrued as malicious in this thread.
"..i am done with Mr. Dieckmann...."
I just tried to ask a few simple questions with no real malice. You would no doubt reply if I was to trade barbs, but everyone is tired of that and if you won't take the time to insult me in Latin anymore, so what fun is it?
I meant to ask if the no difference referred to the sonics and not the measurements. I still don't see what the secret is about which commercial amp(s) uses the double pole double zero topology and am interested, as are others, I would imagine.
Will someone else ask, since I have been boycotted despite my real efforts to drag this out of the mud and up to the level of civil discourse. I will try to be even more sensitive and leave out anything that could be misconstrued as malicious in this thread.
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