Hi Thanks for reading.
I have an asus stxII soundcard and am suffering a lot of treble loss, something about the card is attenuating the high frequencies.
The card uses 3 opamps, two muse8920 and one muse8820. I noticed from the datasheet the 8820 has a very low slew rate of 5V/µs, i have a few other opamps the opa627, the jrc 2114d , opa827, lm 4562 and the slew rate on these opamps is much higher 20-30 V/µs
With the faster slew rate opamps the treble loss problem disappears, but returns with the muse 8820, but the thing about the muse 8820 is that the midrange and bass sounds much better, more detailed than any of the other opamps.
Why do you think this is? Is a low slew rate detrimental for treble response, and beneficial for bass and midrange response. Why should this be, do you have an explanation for this.
I have an asus stxII soundcard and am suffering a lot of treble loss, something about the card is attenuating the high frequencies.
The card uses 3 opamps, two muse8920 and one muse8820. I noticed from the datasheet the 8820 has a very low slew rate of 5V/µs, i have a few other opamps the opa627, the jrc 2114d , opa827, lm 4562 and the slew rate on these opamps is much higher 20-30 V/µs
With the faster slew rate opamps the treble loss problem disappears, but returns with the muse 8820, but the thing about the muse 8820 is that the midrange and bass sounds much better, more detailed than any of the other opamps.
Why do you think this is? Is a low slew rate detrimental for treble response, and beneficial for bass and midrange response. Why should this be, do you have an explanation for this.
The fact that the midrange/bass sound better with the loss of treble is a normal reaction of our hearing/perception system. Systems with less treble always sound warmer and more detailed in the mid/lows. Its a psycho-acoustic thing.
The loss of treble is extremely unlikely due to low slew rate. Slew rate is a large signal phenomenon, and except for power amps with 10's of volts of output, 5V/us is ample.
These things are quite hard to diagnose without some test equipment. For instance, it may be that the stock amp has a frequency response that droops at the high end. Very often you see that replacing it with a fast opamp makes it oscillate and that can give the impression of more highs, but is of course not a Good Thing.
But since this is a soundcard, with free software like REW you can make a test in 'loop back' (input connected to output) and measure the card flatness.
Jan
The loss of treble is extremely unlikely due to low slew rate. Slew rate is a large signal phenomenon, and except for power amps with 10's of volts of output, 5V/us is ample.
These things are quite hard to diagnose without some test equipment. For instance, it may be that the stock amp has a frequency response that droops at the high end. Very often you see that replacing it with a fast opamp makes it oscillate and that can give the impression of more highs, but is of course not a Good Thing.
But since this is a soundcard, with free software like REW you can make a test in 'loop back' (input connected to output) and measure the card flatness.
Jan
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Anything over 20V/us slew rate is of no use.
Try a different playback software.
And on different playback devices.
Try a different playback software.
And on different playback devices.
I want to add, after looking at that soundcard, that it is a very good card and if you have loss of treble, something is seriously broken, and it is NOT because they used the wrong opamp.
The other thing is, how do you know it is the soundcard and not something else. And, important, how do you know there is loss of treble in the first place? Did you do any testing?
Jana
The other thing is, how do you know it is the soundcard and not something else. And, important, how do you know there is loss of treble in the first place? Did you do any testing?
Jana