mastertech said:
An electric generator is based in the priciple that when a conductor crosses a magnetic field, an potential will be induced in the conductor.
So, electric generators, be it tiny or giantic, louspeakers and dynamic microphones all have the same principles.
Just connect a speaker to an amp mic input and speak in it...
And yes, a microphone, if large enough and submitted to a large acoustic pressure, would generate real power.
This has even been considered to generate power for aircrafts (jet engine noise).
Mr pass you mentioned infinite z
can i see the maths please, cause you confuse me
my calculations dont show infinite z
you see there isnt such a think as infinite in my maths, not yet
hi jorge welcome back
now that you told me i know, i thank you
cheers
can i see the maths please, cause you confuse me
my calculations dont show infinite z
you see there isnt such a think as infinite in my maths, not yet
hi jorge welcome back
now that you told me i know, i thank you
cheers
You will recall that I said a pure current source. There is
no such thing practically, as no practical device will deliver
current from an infinite source impedance.
You can get pretty close though, if you choose to define the
current value as 0 by cutting the wire to the speaker.
Otherwise when we are talking about current sources, we
are really talking about very high but finite impedances.
no such thing practically, as no practical device will deliver
current from an infinite source impedance.
You can get pretty close though, if you choose to define the
current value as 0 by cutting the wire to the speaker.
Otherwise when we are talking about current sources, we
are really talking about very high but finite impedances.
Hi Rodolfo,
I am pleased to read your Post#335.
Back in 1994 when D Self was writing and publishing his notes relating to amplifier linearity, but was completely ignoring output stage inductances and the effect of back-EMF amplifier input via its second input terminal - the NFB node via the output terminal - I challenged him that higher audio frequencies riding the back of bass notes would become distorted and that amplifiers should be tested by injecting a test signal into the output terminal.
He 'rubbished' my letter and replied;- "back-EMFs from reactive loads do not cause detectable intermodulation and even if they did, a higher feedback factor would surely reduce rather than increase the effect"
We must not forget that both a crossover network and cabinet air spring can cause considerable phase shift and back-EMF that is additive/subtractive to driver motor back-EMF, such that back-EMF is not simply due to loudspeaker drivers acting like 'microphones'.
** 15 ohm resistors in parallel with amplifier output.
On some (supposedly low distortion) solid state (NFB) designs I found that such a resistor audibly helped to reduce reproduced distortion whilst increasing test bench measurable distortion and heat dissipation.
I put this down to the resistor forcibly maintaining a lesser load angle and thus also reducing back-EMF induced cross-over distortion.
Still worth trying on many amplifiers !
Cheers ........ Graham.
I am pleased to read your Post#335.
Back in 1994 when D Self was writing and publishing his notes relating to amplifier linearity, but was completely ignoring output stage inductances and the effect of back-EMF amplifier input via its second input terminal - the NFB node via the output terminal - I challenged him that higher audio frequencies riding the back of bass notes would become distorted and that amplifiers should be tested by injecting a test signal into the output terminal.
He 'rubbished' my letter and replied;- "back-EMFs from reactive loads do not cause detectable intermodulation and even if they did, a higher feedback factor would surely reduce rather than increase the effect"
We must not forget that both a crossover network and cabinet air spring can cause considerable phase shift and back-EMF that is additive/subtractive to driver motor back-EMF, such that back-EMF is not simply due to loudspeaker drivers acting like 'microphones'.
** 15 ohm resistors in parallel with amplifier output.
On some (supposedly low distortion) solid state (NFB) designs I found that such a resistor audibly helped to reduce reproduced distortion whilst increasing test bench measurable distortion and heat dissipation.
I put this down to the resistor forcibly maintaining a lesser load angle and thus also reducing back-EMF induced cross-over distortion.
Still worth trying on many amplifiers !
Cheers ........ Graham.
Graham Maynard said:
Dear Graham,
why not to use the 15 (or less?) Ohm good quality resistor in series with the loudspeakers?
I guess that it cause lowering the power, but some back-EMFs might be stopped by this resistor.
This would attenuate back-EMF signal that comes to nfb.
Hi Rodolfo, your work even is interesting because the curve V(vest)+V (Vestw) that you have drawn is not seen often and represents much well the tension course of the Back-EMF, that depend entirely from this parameter.
To do clarity a time completely, the simplified formula that defines the ampitude of the back_EMF is: BluD, ( B= magnetics flux, l=length of wire that cuts flux, uD=mechanical velocity of diaphragm).
A thing that they say a few is that the Back-EMF is the truth ( and nearly only ) phenomenon of primary damping of the cone ( on account of the dynamicses of flux that is produced ). It stands to reason that from the point of view of the amp this tensions are a parameter of trouble in more, but the planner has to it know exact dynamicses of this forces. It's common opinion in this forum that is useful to short-circuit this tensions, but I believe that this select have to be appraised after an accurate study of the internal dynamicses of the a (dynamic) loudspeaker. You notices that the Back_EMF am maximum in proximity of the resonance of the cone, and that in that zone there are the maximum phase rotations. I am doing me a very divergent opinion by the majority of the members , and I believe that the back_EMF are able be a valid tool of reduction of the speaker THDS and IMD if the driver is able to " read it". My studies are slow, but I have elements to believe this...
Ciao
Mauro
To do clarity a time completely, the simplified formula that defines the ampitude of the back_EMF is: BluD, ( B= magnetics flux, l=length of wire that cuts flux, uD=mechanical velocity of diaphragm).
A thing that they say a few is that the Back-EMF is the truth ( and nearly only ) phenomenon of primary damping of the cone ( on account of the dynamicses of flux that is produced ). It stands to reason that from the point of view of the amp this tensions are a parameter of trouble in more, but the planner has to it know exact dynamicses of this forces. It's common opinion in this forum that is useful to short-circuit this tensions, but I believe that this select have to be appraised after an accurate study of the internal dynamicses of the a (dynamic) loudspeaker. You notices that the Back_EMF am maximum in proximity of the resonance of the cone, and that in that zone there are the maximum phase rotations. I am doing me a very divergent opinion by the majority of the members , and I believe that the back_EMF are able be a valid tool of reduction of the speaker THDS and IMD if the driver is able to " read it". My studies are slow, but I have elements to believe this...
Ciao
Mauro
Graham Maynard said:
Hi Graham,
No matter what Mr. Self has acclaimed in his technical notes, But i completely agree with you because the insight statements you are stating are absolutely right to the fact which lies between the Amplifier->Cable lengths->Passive Cross-over->loudspeaker behaviour in the Inductive domain which confers the phase-shift and back -EMF issues regarding this perspective coherency of reactivelessness.....
The tests done on work bench never confers the context what you encounter during field operations and i think Mr.Self is just refering to the traditional workbench test done in lab in controlled and favourable conditions...but EN-Field operation the scenario is somewhat different and engulfs the wide spectrum of different coherent parameters effecting the behaviour of Inductive kickback to what we refer to it as "back EMF"
The inductiveness surely relates to the output node as the back EMF is encountered at the output and thus also encountered by the inverting input node or feedback node of differential pair which certainly changes the distortion figures when driving real world loads......
cheers to you ,
Kanwar
padamiecki said:
Could be. I really don't know.
But I'm sure that most speakers will present a very ragged frequency response under such an amp. Speakers are designed to be fed from very low impedance sources.
If someone is willing to test, a whole new speaker system would have to be dsigned, and then compared to the same drivers in a classical design.
Otherwise, results will be meaningless.
Understanding amplifier output impedance
I must confess we (engineers) are responsible for creating some confusion with statements detached from a certain assumed context. Amplifier output impedance (also referred as damping factor) is a case in point.
A simple battery in series with a resistor, considered as a 2 terminal black box, exhibits a measurable output (also called source) impedance. In fact it can be determined by the quotient of the measured unloaded output voltage and the measured output current now with terminals shorted together.
For the sake of circuit analysis, the black box can be represented as an ideal (0 internal resistance) voltage source in series with the computed source resistance.
This also holds for AC, only now the impedance may exhibit frequency dependent magnitude and phase angle, as determined by the above measurement procedure.
An amplifier can be represented in exactly the same form - to a very good first order aproximation. Only in this case - and here is where confusion frequently arieses - the means to attain a certain (low) output impedance may be purely passive, or active.
A no feedback amplifier will exhibit what I referred above as "passive" output impedance in the sense the circuit topology and component values define "one way" the open circuit voltage and short circuit current from which the output impedance can be computed. (not a recommended method, the desirable low output impedance implies dangerous short circuit currents).
Andy_c presented and alternative and more useful method for evaluating output impedance, as the quotient of the *incremental* voltage change to current change. It is more useful since the output impedance is not a constant but depends among other variables on total current and to a lesser degree on output voltage.
An active system for its part, as is a negative feedback voltage amplifier, senses the deviations from desired output voltage and drives the power stage to compensate it. The effect when we measure the open circuit voltage to short circuit current ratio (or incremental ratio), is it results much lower than the one measured for the same output stage with no feedback. It is worth noting that a simple emitter follower implies local feedback and is thus an active topology.
The net effect is then to actively "build" an equivalent output impedance much lower than the starting one. This is why we say NFB acts to reduce output impedance (or improve damping).
For this to work as advertised, the output stage must have built-in the capability to obey what the feedback correction tells it to do.
And for this to be true for AC within the working frequency range, both the output stage and the whole control loop must keep the desired behavior.
From the standpoint of a 2 terminal "black box", it is irrelevant whether the effective measured output impedance is attained in a purely passive fashion, or actively with feedback.
Rodolfo
I must confess we (engineers) are responsible for creating some confusion with statements detached from a certain assumed context. Amplifier output impedance (also referred as damping factor) is a case in point.
A simple battery in series with a resistor, considered as a 2 terminal black box, exhibits a measurable output (also called source) impedance. In fact it can be determined by the quotient of the measured unloaded output voltage and the measured output current now with terminals shorted together.
For the sake of circuit analysis, the black box can be represented as an ideal (0 internal resistance) voltage source in series with the computed source resistance.
This also holds for AC, only now the impedance may exhibit frequency dependent magnitude and phase angle, as determined by the above measurement procedure.
An amplifier can be represented in exactly the same form - to a very good first order aproximation. Only in this case - and here is where confusion frequently arieses - the means to attain a certain (low) output impedance may be purely passive, or active.
A no feedback amplifier will exhibit what I referred above as "passive" output impedance in the sense the circuit topology and component values define "one way" the open circuit voltage and short circuit current from which the output impedance can be computed. (not a recommended method, the desirable low output impedance implies dangerous short circuit currents).
Andy_c presented and alternative and more useful method for evaluating output impedance, as the quotient of the *incremental* voltage change to current change. It is more useful since the output impedance is not a constant but depends among other variables on total current and to a lesser degree on output voltage.
An active system for its part, as is a negative feedback voltage amplifier, senses the deviations from desired output voltage and drives the power stage to compensate it. The effect when we measure the open circuit voltage to short circuit current ratio (or incremental ratio), is it results much lower than the one measured for the same output stage with no feedback. It is worth noting that a simple emitter follower implies local feedback and is thus an active topology.
The net effect is then to actively "build" an equivalent output impedance much lower than the starting one. This is why we say NFB acts to reduce output impedance (or improve damping).
For this to work as advertised, the output stage must have built-in the capability to obey what the feedback correction tells it to do.
And for this to be true for AC within the working frequency range, both the output stage and the whole control loop must keep the desired behavior.
From the standpoint of a 2 terminal "black box", it is irrelevant whether the effective measured output impedance is attained in a purely passive fashion, or actively with feedback.
Rodolfo
Hi everybody,
after lurking for a while, I'll add my 2c to this quite interesting discussion...
I would say more than just that. It seems to me that many people tend to "forget" that a loudspeaker is:
a) a non-linear device!
==> it is NOT possible to properly model the "Back_EMF" using only linear devices! (such as Rs, Ls and Cs).
[and that's not a minor thing: the distorsion of a loudspeaker can be several orders of magnitude higher than that of the amplifier driving it...].
b) a bi-directional transducer
==> any sound facing the loudspeaker is converted back to an electric signal!
That is, all the countless reflections coming from the environment in which the loudspeaker is operated (enclosure + listening room + ...), modified by all the resonances (and non linearities) of this complex environment, plus any other "extraneous" noise... all of that appears back at the loudspeaker terminals!
(not to mention that in a stereo setup one have the signal from one channel injected back in the other via this form of "acoustical coupling"...).
Given the transient and non-periodic nature of any real musical signal and the long delays of the acoustical reflections, at any given moment the "Back_EMF" signal can be quite different from the amplifier input at that same time.
Thus the effects on the (instantaneous) amplifier behavior may be much more substantial that those revealed by any simpler experimental conditions...
BTW, speaking about distorsion, perceived sound quality and "creative" unusual audio measurements...
IMHO I believe that unfortunately the only way to do a "real" test to qualify (and possibly somehow "quantify") the perceived "audio quality" (distorsions et al) of an audio system would be to actually drive a real loudspeaker in a real environment using a "real" signal (*) and then "look at" the real "output" of the system, that is, listen to and measure the real acoustical output of the whole system using a microphone!
(*) e.g. possibly those very same pieces of music signal one use for the listening test... or at least some "synthetic" test signal which is a good representation of a real signal. That is, it must be of a non-periodic, transient nature, with strong peaks followed by weak signals, with music-like timings, etc...
Needless to say, such a measurement would be rather tricky, if at all feasible. 🙁
...but it would be something quite interesting to discuss, anyway... and I have a few
rough idea on how something like that (maybe) could be done... 😉
after lurking for a while, I'll add my 2c to this quite interesting discussion...
mauropenasa said:
I would say more than just that. It seems to me that many people tend to "forget" that a loudspeaker is:
a) a non-linear device!
==> it is NOT possible to properly model the "Back_EMF" using only linear devices! (such as Rs, Ls and Cs).
[and that's not a minor thing: the distorsion of a loudspeaker can be several orders of magnitude higher than that of the amplifier driving it...].
b) a bi-directional transducer
==> any sound facing the loudspeaker is converted back to an electric signal!
That is, all the countless reflections coming from the environment in which the loudspeaker is operated (enclosure + listening room + ...), modified by all the resonances (and non linearities) of this complex environment, plus any other "extraneous" noise... all of that appears back at the loudspeaker terminals!
(not to mention that in a stereo setup one have the signal from one channel injected back in the other via this form of "acoustical coupling"...).
Given the transient and non-periodic nature of any real musical signal and the long delays of the acoustical reflections, at any given moment the "Back_EMF" signal can be quite different from the amplifier input at that same time.
Thus the effects on the (instantaneous) amplifier behavior may be much more substantial that those revealed by any simpler experimental conditions...
BTW, speaking about distorsion, perceived sound quality and "creative" unusual audio measurements...
IMHO I believe that unfortunately the only way to do a "real" test to qualify (and possibly somehow "quantify") the perceived "audio quality" (distorsions et al) of an audio system would be to actually drive a real loudspeaker in a real environment using a "real" signal (*) and then "look at" the real "output" of the system, that is, listen to and measure the real acoustical output of the whole system using a microphone!
(*) e.g. possibly those very same pieces of music signal one use for the listening test... or at least some "synthetic" test signal which is a good representation of a real signal. That is, it must be of a non-periodic, transient nature, with strong peaks followed by weak signals, with music-like timings, etc...
Needless to say, such a measurement would be rather tricky, if at all feasible. 🙁
...but it would be something quite interesting to discuss, anyway... and I have a few
rough idea on how something like that (maybe) could be done... 😉
UnixMan said:
Paolo:
You are right in that a speaker is both a nonlinear device and also a bi-directional transducer.
But both factors must first be qualified before being factored in the overall result, and anyway it is only possible to make progress by first segregating problems of different nature as much as feasible and tackling them one by one before reconstructing the complete picture.
The linear model is a very good aproximation, and as such allows to analyze and devise means for coping with undesirable effects in a convenient way. The issues of voice coil control and of load phase angle impact on amplifier operation are very real and manageable with the linear model.
The speaker nonlinearity is something about what little can be done except for acoustic feedback (which relates to the last part of your post).
With respect to microphonism, it was remarked in earlier posts that its magnitude is not only small, but also a low amplifier effective output impedance acts as a short circuit reducing even further its effects. The same goes for speaker distortion derived "back EMF".
As for new, different and innovative test ideas, the more the better. Useless ones will be weeded out, and who knows, it has happened and will keep happening that crazy or accidentally originated experiments lead to unexpected results.
Rodolfo
Hi Kanwar,
I can understand your earlier stated need for reliability using high current output bipolars for public performances - in a circuit that suits them !
Put a high power driver in an 'efficient' cabinet at the end of a long wire and drive it with a 'high-fidelity' amplifier and if it doesn't blow up it or pick up taxis or the local FM it often generates seriously lifeless sound because of internal amplifier inductance and the high damping factor.
( There little more publically embarrasing than sudden silence. )
Hi padamiecki,
Why not try it ? Some loudspeaker systems start losing treble detail with as little as 0.22 ohms in series. As Jorge suggests, it is down to loudspeaker design.
Hi Rodolfo,
But are there not differences between passive and active damping ?
Passive damping is always there, thus instantly acting and more likely to be resistive.
Active damping is NFB loop generated and has propagation delay which can lead to an inductive output characteristic.
Active damping can only be as good as passive if the feedback loop bandwidth is sufficient to cause negligible phase error at audio frequencies; one reason why Miller C.doms can cause sound reproduction problems.
But even this activitity holds only for as long as the amplifier is acting linearly and not running out of output current or being inadvertantly voltage clipped.
This is one reason why I am not yet convinced that digital amplifiers will sound as good as analogue. There is a fundamental switching NFB correction delay and then series output inductors. Digital might be okay for forward amplification into a resistor or a full range driver, but what about back-EMF control with a composite loudspeaker system ?
Hi Paolo,
Quite so.
And I wonder how many T-S exponents realise that voice coil inductance behaves non-linearly with amplitude too. Inductance falls with increasing amplitude such that back-EMF falls and resistive voice coil currents rise.
Little wonder that speakers get hot (or worse) when driven hard !
Cheers ........ Graham.
I can understand your earlier stated need for reliability using high current output bipolars for public performances - in a circuit that suits them !
Put a high power driver in an 'efficient' cabinet at the end of a long wire and drive it with a 'high-fidelity' amplifier and if it doesn't blow up it or pick up taxis or the local FM it often generates seriously lifeless sound because of internal amplifier inductance and the high damping factor.
( There little more publically embarrasing than sudden silence. )
Hi padamiecki,
Why not try it ? Some loudspeaker systems start losing treble detail with as little as 0.22 ohms in series. As Jorge suggests, it is down to loudspeaker design.
Hi Rodolfo,
But are there not differences between passive and active damping ?
Passive damping is always there, thus instantly acting and more likely to be resistive.
Active damping is NFB loop generated and has propagation delay which can lead to an inductive output characteristic.
Active damping can only be as good as passive if the feedback loop bandwidth is sufficient to cause negligible phase error at audio frequencies; one reason why Miller C.doms can cause sound reproduction problems.
But even this activitity holds only for as long as the amplifier is acting linearly and not running out of output current or being inadvertantly voltage clipped.
This is one reason why I am not yet convinced that digital amplifiers will sound as good as analogue. There is a fundamental switching NFB correction delay and then series output inductors. Digital might be okay for forward amplification into a resistor or a full range driver, but what about back-EMF control with a composite loudspeaker system ?
Hi Paolo,
Quite so.
And I wonder how many T-S exponents realise that voice coil inductance behaves non-linearly with amplitude too. Inductance falls with increasing amplitude such that back-EMF falls and resistive voice coil currents rise.
Little wonder that speakers get hot (or worse) when driven hard !
Cheers ........ Graham.
Graham Maynard said:
Hi Graham,
Well i dont use Bipolars at outputs , I use high power large die N-channel mosfets at output.....I cant agree with you that high damping factor yields "Lifeless-Sound" , It doesnot means than amplifier has no inductance at output, but it has and always interacts with the other parameters influencing the sound quality....
Regards,
Kanwar
Hi Kanwar,
From simulating the resverse injection of amplifiers I have noted that Mosfets do not have the same back-EMF driven reverse commutation through a fraction of their bias voltage as do many bipolar amps, so my above comment to you should have been limited to the likes of bipolar hi-fi, though as you say effects that are possible due to high damping will arise equally whatever the output devices.
Cheers ......... Graham.
From simulating the resverse injection of amplifiers I have noted that Mosfets do not have the same back-EMF driven reverse commutation through a fraction of their bias voltage as do many bipolar amps, so my above comment to you should have been limited to the likes of bipolar hi-fi, though as you say effects that are possible due to high damping will arise equally whatever the output devices.
Cheers ......... Graham.
Hi Graham,
So Do you agree that mosfet output stage is far superior than bipolar output stage....I am not satisfied with your statement that high damping factor doesnot restricts the effect of back emf in comparision with low damping factor amp...In fact Hi-DF counteracts more than LO DF ....
Cheers,
Kanwar
So Do you agree that mosfet output stage is far superior than bipolar output stage....I am not satisfied with your statement that high damping factor doesnot restricts the effect of back emf in comparision with low damping factor amp...In fact Hi-DF counteracts more than LO DF ....
Cheers,
Kanwar
Graham Maynard said:
Hi Graham,
do I understand you right that MOSFET's as output transistors are less prone to the EMF drawback issue due to the above quote of you?
What is actually happening in a real amplifier circuit with output transistors MOSFET's VS BJT's?
Another questions, would you say there are any problem with loudspeaker EMF and some amplifiers:
* at impedance peaks and impedance dips?
* at falling impedance area of loudspeakers impedance with rising frequency?
Would you say loudspeaker EMF is a problem for the second input node in all amplifier, eg. the feedback node, and is it the only or partial biggest problem, or what is the partial biggest problem from your standpoint?
Regards Michael
Graham Maynard said:
Yes Graham, this are exactly the 2 prerequisites I proposed several posts back (#148) so no contradiction here.
Nowadays there are no excuses for not achieving both conditions for home power levels at negligible cost. Wideband power devices are plentifull and the same holds for multimegaherz low noise and distortion audio operational amplifiers.
Rodolfo
Hi Kanwar,
I did not say that a high damping factor does not restrict the effect of back-EMF within an amplifier - it does, however, because of gate capacitance Mosfet damping is much more likely to be in quadrature than with bipolar amplifier damping at mid/high AF frequencies. (there are of course some poorly designed bipolar topologies too.)
It is when the damping is in quadratue that back-EMF can overcome biasing before the NFB loop regains control. Mosfet biasing has a longer low level transconduction base than the near switching characteristics of a bipolar, so a Mosfet common drain output stage is not as easily reverse driven into fractional bias commutation, and when it does happen, it simulates more gradually and further away from the zero ac voltage level - less dissonant ?
Mosfet amplifiers can sound very smooth and well controlled but I prefer phase coherent crossover/loudspeaker damping for clean hf detail, and this is why I stick with bipolars.
Hi Michael,
Any amplifier that has low amounts of quadrature damping can be bothered by some loudspeakers.
I'm only passing on obsevations, so I cannot say for sure exactly what will be a triggering factor.
Voltage amplifier current energisation of a composite loudspeaker changes considerably during the first cycle of any musically changing input as the loudspeaker builds up its back-EMF, and by the time that back-EMF has developed the music has moved on. If the amplifier correction is in quadrature I wonder where this leaves reproduction when the loudspeaker's electrical response is itself not in phase.
Cheers ........ Graham.
I did not say that a high damping factor does not restrict the effect of back-EMF within an amplifier - it does, however, because of gate capacitance Mosfet damping is much more likely to be in quadrature than with bipolar amplifier damping at mid/high AF frequencies. (there are of course some poorly designed bipolar topologies too.)
It is when the damping is in quadratue that back-EMF can overcome biasing before the NFB loop regains control. Mosfet biasing has a longer low level transconduction base than the near switching characteristics of a bipolar, so a Mosfet common drain output stage is not as easily reverse driven into fractional bias commutation, and when it does happen, it simulates more gradually and further away from the zero ac voltage level - less dissonant ?
Mosfet amplifiers can sound very smooth and well controlled but I prefer phase coherent crossover/loudspeaker damping for clean hf detail, and this is why I stick with bipolars.
Hi Michael,
Any amplifier that has low amounts of quadrature damping can be bothered by some loudspeakers.
I'm only passing on obsevations, so I cannot say for sure exactly what will be a triggering factor.
Voltage amplifier current energisation of a composite loudspeaker changes considerably during the first cycle of any musically changing input as the loudspeaker builds up its back-EMF, and by the time that back-EMF has developed the music has moved on. If the amplifier correction is in quadrature I wonder where this leaves reproduction when the loudspeaker's electrical response is itself not in phase.
Cheers ........ Graham.
Graham Maynard said:
Please explain and/or define with exacting attention to detail and with precision the following:
and:
Mr kanwar great to see you back
mr maynard
"lifeless sound"
i dont agree with that
mr kanwar
"So Do you agree that mosfet output stage is far superior than bipolar output stage"
i dont agree with that
mr kanwar
"Well i dont use Bipolars at outputs , I use high power large die N-channel mosfets at output"
i can understand why
mr kanwar if you like higher damping use bjt oops!
hi ms mikeks are you a writer of ew,is there a link where i
can download free articles,thanks in advance
cheers
mr maynard
"lifeless sound"
i dont agree with that
mr kanwar
"So Do you agree that mosfet output stage is far superior than bipolar output stage"
i dont agree with that
mr kanwar
"Well i dont use Bipolars at outputs , I use high power large die N-channel mosfets at output"
i can understand why
mr kanwar if you like higher damping use bjt oops!
hi ms mikeks are you a writer of ew,is there a link where i
can download free articles,thanks in advance
cheers
- Status
- Not open for further replies.