I have an interesting question for Sir Nelson:
It says .8 doesn't use compensation cap, which is a great thing.
I wonder though, how is the square wave response with pure resistive load (or no load for what it matters)?
Do you accept eventual undershoot and over shoot or do you only look at the stability with a capacitive response?
Because it's my experience that even a big amplifier can be made stable with the right topology and right values without compensation cap, but I always found that suqre wave response will have some overshoot if no input shaping filter is introduced but yet remaining stable on a capacitive load with 2.2uF.
I am wondering if you shape out the signal at the input with the filter or you got rid of that and if so if you care about having a smooth square wave, which I think it is more for magazines and such than for actual functionality.
Hope my question came across clear.
It says .8 doesn't use compensation cap, which is a great thing.
I wonder though, how is the square wave response with pure resistive load (or no load for what it matters)?
Do you accept eventual undershoot and over shoot or do you only look at the stability with a capacitive response?
Because it's my experience that even a big amplifier can be made stable with the right topology and right values without compensation cap, but I always found that suqre wave response will have some overshoot if no input shaping filter is introduced but yet remaining stable on a capacitive load with 2.2uF.
I am wondering if you shape out the signal at the input with the filter or you got rid of that and if so if you care about having a smooth square wave, which I think it is more for magazines and such than for actual functionality.
Hope my question came across clear.
Last edited:
I like to avoid overshoot as a practical matter, as I have not preferred the
sound of many amplifiers that have it.
There is no undershoot, only limited RC time constant, which I don't find to be a
problem if the bandwidth is adequate, which is about 100 Khz or so.
It so happens that these amplifiers do not need capacitors (except as filters
across the supplies and bias circuits), but it was not a design goal.
sound of many amplifiers that have it.
There is no undershoot, only limited RC time constant, which I don't find to be a
problem if the bandwidth is adequate, which is about 100 Khz or so.
It so happens that these amplifiers do not need capacitors (except as filters
across the supplies and bias circuits), but it was not a design goal.
Thank you Sir Nelson!
Only one extra point here
! Let's say the amplifier is stable without any compensation cap, in other words it doesn't oscillate and it controls a capacitive load with no problem.
However on the square wave response it has overshoot.
Adding an input filter with 200KHz or so will fix it because it will limit the bandwidth and the overall response will be very pretty
Would this correct the sonic problem you find with amps that don't have a good square wave response?
In my opinion it would only mean adding a patch to the problem and mask it by limiting the input signal, but I would be interested in your take on this.
Only one extra point here
! Let's say the amplifier is stable without any compensation cap, in other words it doesn't oscillate and it controls a capacitive load with no problem.However on the square wave response it has overshoot.
Adding an input filter with 200KHz or so will fix it because it will limit the bandwidth and the overall response will be very pretty
Would this correct the sonic problem you find with amps that don't have a good square wave response?
In my opinion it would only mean adding a patch to the problem and mask it by limiting the input signal, but I would be interested in your take on this.
XA200.5 vs XA200.8
A question for Mr. Pass...
I currently own a set of XA200.5 which I love, and awaits a set of XA200.8 when they are ready to ship.
Can you tell me a little about what I can expect from the upgrade ?
I haven´t bee able to find much info on the differences apart from a new front end and lower output current ??
System: Arc Ref3, DCS Puccini + U-clock, Sonus Faber Stradivari, Clearaudio Champion Level 2/ SMEV/ Benz-Micro ACE-s, Arc PH7, Cables from Shunyata, Kondo and Nordöst.
looking forward to your reply.
A question for Mr. Pass...
I currently own a set of XA200.5 which I love, and awaits a set of XA200.8 when they are ready to ship.
Can you tell me a little about what I can expect from the upgrade ?
I haven´t bee able to find much info on the differences apart from a new front end and lower output current ??
System: Arc Ref3, DCS Puccini + U-clock, Sonus Faber Stradivari, Clearaudio Champion Level 2/ SMEV/ Benz-Micro ACE-s, Arc PH7, Cables from Shunyata, Kondo and Nordöst.
looking forward to your reply.
That's a hypothetical. An input filter might correct overshoot, and the square
wave would be more pretty, but it's a presumption to say that it's a sonic
problem. There are amplifiers that people think sound good without a pretty
square wave.
In all cases, the .8 products are examples of more and better in varying
degrees. In the XA200.8 the improvements are less in the way of bigger
hardware - most of what you will experience is the improvement of the new
front end and the single-ended current sources on the output stage.
Nevertheless, the result is pretty dramatic by all accounts. I think that when
you hear it, you will know what I mean.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.