Be aware of the digital sonic artifacts (aliasing) in your KPA!

    Quote from ballantine

    About the clip 1 and 2 I can definitely hear the artifacts in your clips, but I never noticed that on my KPA with my profiles... I don't know if it is something only related to that profile or you have similar problems with other profiles.



    3) I don't understand. Are you setting every other gear's digital clock to slave? If not it's very regular that you'll have those clicks...



    Dan, In the interest of full disclosure, those sound files were done during the summer on the latest firmware at the time, and were already posted on this thread back then. You raise an important question about selecting "clean" when profiling, and I am reasonably sure I did that. I plan to do new clean profiles tomorrow with a more recent firmware version and will let you know what I discover.


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    Ballantine, In all my S/PDIF tests, my Avid HD 192, Crane Song Avocet, and a consumer D to A were slaving to the KPA, and trying 3 different brands of digital cable, I experienced random and varying ticks that would sometimes go away with a rig change, but only to return at a later time.

    In contrast I use my Kemper almost 100% through SPDIF so as to avoid the DAC latency. Never have clicks or pops, in fact it works perfectly. There has to be either something wrong with your unit or your settings but suffice to say it does work on other units. :)

    Quote from miles


    Ballantine, In all my S/PDIF tests, my Avid HD 192, Crane Song Avocet, and a consumer D to A were slaving to the KPA, and trying 3 different brands of digital cable, I experienced random and varying ticks that would sometimes go away with a rig change, but only to return at a later time.


    I too used to have a lot of clicks/crackles via SPDIF that would go away with rig change only to return later. But a while back KPA support did some changes to remedy the situation and with couple of the latest public beta FWs I have not had the clicks anymore.



    These files are five months old.
    Is this problem still present?
    It should take you a minute to check a clean sound with the actual version-


    BTW: Clean setting for the profiling does not make a difference, it just lowers the test signal volume.

    Have to say that I just noticed a "user" mistake I been doing, as I locked my input (clean sense 2,0, distortion sense 0,0) , and so had much more gain in some profiles than they should have. One of Andys EVH5150 rigs been on 1,8 (clean) and -3,3 (dist.) so with my locked distortion sense 0,0 that rig had much more gain than designated by Andy. That also increased the aliasing on such rigs, but it´s still there (but less) when unlocking the input.

    Quote from mikeb

    In contrast I use my Kemper almost 100% through SPDIF so as to avoid the DAC latency. Never have clicks or pops, in fact it works perfectly. There has to be either something wrong with your unit or your settings but suffice to say it does work on other units. :)


    There are clicks that you can hear and some that you can't but they are present.
    The last firmware (5.2) solved the spdif/click issue for me.

    Quote from ACY

    Have to say that I just noticed a "user" mistake I been doing, as I locked my input (clean sense 2,0, distortion sense 0,0) , and so had much more gain in some profiles than they should have. One of Andys EVH5150 rigs been on 1,8 (clean) and -3,3 (dist.) so with my locked distortion sense 0,0 that rig had much more gain than designated by Andy. That also increased the aliasing on such rigs, but it´s still there (but less) when unlocking the input.


    Why would distortion sense at 0 increase the gain over what was intended when taking the profile?

    I had my input locked at dist. sense 0,0, so Andys profile now worked with my 0,0 distortion sense, and not with Andys saved -3,3 distortion sense. So with my 0,0 the rig has much more gain than with non locked input and taking Andys -3,3 setting.

    Quote from ACY

    I had my input locked at dist. sense 0,0, so Andys profile now worked with my 0,0 distortion sense, and not with Andys saved -3,3 distortion sense. So with my 0,0 the rig has much more gain than with non locked input and taking Andys -3,3 setting.

    Ummmm...why would you not simply turn the gain down? While many of Andy's profiles are certainly playable out of box, they're even better if tweaked to your guitar and monitoring situation.

    Quote from ckemper

    These files are five months old.
    Is this problem still present?
    It should take you a minute to check a clean sound with the actual version-


    BTW: Clean setting for the profiling does not make a difference, it just lowers the test signal volume.


    Today I did some fresh testing with 1.5.2 installed and have found:


    [1] The aliasing I heard previously on clean profiles is now virtually non-existent--this is a very good sign.


    [2] The aliasing on high-gain profiles unfortunately is still there--not a good sign.


    [3] The distortion on clean profiles that I demonstrated on that previous sound file still exists. I created a brand new clean profile today that demonstrates the same thing I noticed months ago--on this sound file, what you hear on the first 4 strums is a Great River MP-2NV Preamp/DI direct to an Avid 192 HD via the KPA and into Pro Tools, and the next 4 strums are the profile of the Great River (both are A/B'ed from the profiler screen). All gains on all devices are set chilly-cool to avoid any chance of distortion at any stage, and what you hear, I believe, is the KPA still imposing a gritty distortion to an otherwise pristine signal. I used a Strat with a Duncan Custom Trembucker, and although the A/B'ed parts sound tonally a little different, it's partly because of the way I strummed it, and partly due to the profile itself.


    Great River-KPA Clean Test 1

    Edited 3 times, last by miles ().

    Quote from miles

    [3] The distortion on clean profiles that I demonstrated on that previous sound file still exists. I created a brand new clean profile today that demonstrates the same thing I noticed months ago--on this sound file, what you here on the first 4 strums is a Great River MP-2NV Preamp/DI direct to an Avid 192 HD via the KPA and into Pro Tools, and the next 4 strums are the profile of the Great River (both are A/B'ed from the profiler screen). All gains on all devices are set chilly-cool to avoid any chance of distortion at any stage, and what you hear, I believe, is the KPA still imposing a gritty distortion to an otherwise pristine signal. I used a Strat with a Duncan Custom Trembucker, and although the A/B'ed parts sound tonally a little different, it's partly because of the way I strummed it, and partly due to the profile itself.


    Great River-KPA Clean Test 1


    You mean that your KPA profile from your MP-2NV Preamp is set with gain at 0 and still distorts?

    Quote from miles

    Yes.


    The 2 parts on the clip sound different. Maybe the profile and the preamp are reacting differently to the same input level. It sounds a bit like the 2nd one is being overdriven just a bit. Are you able to make it as clean as the 1st part if you play with the clean sense or decrease your guitar volume?

    Quote from MadH

    The 2 parts on the clip sound different. Maybe the profile and the preamp are reacting differently to the same input level. It sounds a bit like the 2nd one is being overdriven just a bit. Are you able to make it as clean as the 1st part if you play with the clean sense or decrease your guitar volume?

    The clean sense is at 0.0, and don't pay attention to the tonal change, as I did this over and over with all kinds of variations in every possible gain stage, and the distortion was always there--of course if I turn down the guitar the distortion lessens, but I don't think that the distortion is really caused by me driving it, as much as it is the KPA imposing it. The difference in those two takes is that they were done a few minutes apart, and I probably didn't refine that profile, that time, and it doesn't matter really, refined or not... still distorts. My goal was to make the MP-2NV and it's interfacing to the profiling process to be as transparent as possible. I would love to wrong about this, but I have spent hours testing this one issue, and I can't find a fault that I may have overlooked... yet. :thumbup:

    Edited 3 times, last by miles ().