10v/ms vs 30-35v/ms?i see meny amp brands new models with 10v/ms slew rate.can compare with 35-40v/ms amps on sound reproduction performance?
After a bunch of built audio amplifier topologies, after years and years, I could say that the slew rate value matters less (i.e. if, it's 10 or 15V / us, so I mean close values), than the harmonic response of the amplifier.
So, I recommend that you improve the harmonic response of your audio amplifier (in other words, less odd harmonics in the case of solid state topologies).
As in the case of tubes, the even harmonic response is more pleasing to the human ear and in the case of solid-stage audio amplifiers this desideratum should be pursued (although it is more difficult, because semiconductors triumph over odd harmonics). Of course, a combination of topology with current reaction and voltage amplification, at least at the moment, is the best compromise when we want to get a maximum in audio (with solid state topologies).
i own booth slow and high rate.i read few days a go somewhere the high slew rate amps is faster in transients than others with low v/ms
REMEMBER THIS! It is faster if the slewrate is higher, but you remember an important aspect, indeed, big differences of slewrates matter, but it is much more important to have on the output of the solid state audio amplifier a small content of odd harmonics at various test signals (for different frequencies). It is necessary to achieve this goal to make the audio amplifier sound more pleasant. The rest of the technical details are less important.
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I've never seen slew rate specified in milliseconds. 35V/ms is awfully slow, I don't know any amp that is that bad.
I even think an amp with 35V/ms cannot do audio, 35mV/uS ??
Do the sums.
Where did you get this?
Jan
Slew rates on common chip amps:
LM1875 8 V/us
LM3886 19 V/us
LME49810 50 v/us
TDA2050 8 V/us
TDA7293 10V/us
TDA7294 10V/us
LM1875 8 V/us
LM3886 19 V/us
LME49810 50 v/us
TDA2050 8 V/us
TDA7293 10V/us
TDA7294 10V/us
Slew rate is given according bandwidth : the higher (in V/uS vs F) seems the better. This is partially false IF not considering Z and level ... IMHO, a lower bandwidth will be more satisfying IF noisefloor is lower and spectral density is higher 😉
SR is the maximum slope the amplifier can follow. it is the steepest when the wave is at 0-crossing.
lets calculate for a full scale sine wave with 20kHz, the amplitude be 30V.
A= peak amplitude; cos=1 at 0-crossing
30V*2*pi*20kHz= 3.77V/us
so any amp with a slew rate >4V/us can reproduce the signal without creating additional distortion.
There is no advantage of a higher SR.
lets calculate for a full scale sine wave with 20kHz, the amplitude be 30V.
A= peak amplitude; cos=1 at 0-crossing
30V*2*pi*20kHz= 3.77V/us
so any amp with a slew rate >4V/us can reproduce the signal without creating additional distortion.
There is no advantage of a higher SR.
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slew rate differ on frequencies?same amp on100hz other rate than 10khz.if i use an amp only to drive compresion drivers and try it on subwoofers? in my experiences and tests i made from my dynacord ev crown crest i found the high slew rate amps is better in general rule.another question is the load 8 or 4 ohm plays important role to slew rate? same amp gives other numbers on 8ohm and worse or better on lower impedance?
Slew rate is simply measures the amplifier's ability to respond to changes in input signals , not just audio but also in industrial systems.
ST says somewhere in its old TDA 20xx data sheets that too high a slew rate will cause problems.
In audio systems, as a thumb rule, more than 12 or so is excessive.
You have to then consider the power supply and speaker response too, and also the ability of us humans to appreciate the system response.
But if you can make out what kind of drum is being played, and clear vocals, all is well.
But if you can tell if a guitar is being played with a copper coin, or a plastic pick, then you are unusual.
Brian May, of Queen, used a copper penny as a pick, and plastic picks are more frequent among guitar players.
Very high slew rates are encountered in industrial servo systems, and the 2050 was also used there apart from audio systems.
ST says somewhere in its old TDA 20xx data sheets that too high a slew rate will cause problems.
In audio systems, as a thumb rule, more than 12 or so is excessive.
You have to then consider the power supply and speaker response too, and also the ability of us humans to appreciate the system response.
But if you can make out what kind of drum is being played, and clear vocals, all is well.
But if you can tell if a guitar is being played with a copper coin, or a plastic pick, then you are unusual.
Brian May, of Queen, used a copper penny as a pick, and plastic picks are more frequent among guitar players.
Very high slew rates are encountered in industrial servo systems, and the 2050 was also used there apart from audio systems.
When I made a phono pre amp, I put a socket, and used the TL072, but for fun I also put the 358 and 4558 to see what happened, playing 'Hotel California', which is my test piece because of the drum and guitar passages.
358 was dull, and 4558 was not so good, the 072 needed changes in impedance, and worked.
The 358 has a low slew rate, only 0.3 , 4558 also 1.2, 5532 about 9 and 072 is 13.
I was driving amps (2030/1875) with a lower slew rate than the 072, and settled on that.
It worked, and the friend I built it for was happy.
The tonal response also has to be assessed, and some people like more bass than others, and the speakers also play a part.
To sum up, choose what you feel is best. There is not much to choose from in most designs, and what you build or buy is also influenced by what is available.
358 was dull, and 4558 was not so good, the 072 needed changes in impedance, and worked.
The 358 has a low slew rate, only 0.3 , 4558 also 1.2, 5532 about 9 and 072 is 13.
I was driving amps (2030/1875) with a lower slew rate than the 072, and settled on that.
It worked, and the friend I built it for was happy.
The tonal response also has to be assessed, and some people like more bass than others, and the speakers also play a part.
To sum up, choose what you feel is best. There is not much to choose from in most designs, and what you build or buy is also influenced by what is available.
You should try your self the sound different of low slew rate and high slew rate in amplifier. You can build same amplifier's topology but with significant different of the slew rate. Design amplifier with high slew rate is easy. Several amplifier in this forum have very high slew rate.