Profiling a Reference Amp - Clean vs Distortion

    In reading thru the literature I see that when profiling, you want to tell the Kemper which you're doing: a clean profile or a distortion profile. My question is suppose that you create a clean profile. When you dial up the gain on a clean profile, how will this differ from the distortion profile for that same amp?


    My guess is that what you're really doing is hearing the effect of saturating the pre-amp tubes on the reference amp as opposed to the power amp tubes. Therefore the quality of the distortion won't be as rich. So separate profiles are created for the Clean, Crunch and Lead channels in order to more accurately capture the various stages of tube saturation of the reference amp.


    Could one of you engineering geeks :) confirm this for me or else set me straight? I imagine this might be useful to others as well. Thanks.

    The KPA will still know if it profiles a distorted amp or channel or clean, even when choosing the right or wrong setting at the beginning of the profiling. The test algorithm times are only slightly different in volume when profiling. Meaning the clean amp will be run louder with the test tones than the distorted amp...the result will still be the shame and the KPA even will tell you that you have chosen clean instead of distortion or vise versa. That doesn't alter the results tho. :)

    The first part of the profile process - seams to find the point where the amp starts to distort - by increasing the level (a lot).


    Since a distortet amp starts to compress this signal - it will not be VERY loud.


    If the same signal would be send into a clean amp it would be VERY loud.

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    to point on point answer your question is that according to KPA any clean profile can be distorted until hi-gain and any high-gain profile can be cleaned up.This enables you to create a lot of different characters on your different profiles. Don't forget, you are taking a snapshot of the amp when you are profiling it and the profile itself can be worked into many different sounds that the basic profile of your amp can give you.


    The clean or distortion setting for the actual profiling session has nothing to do with your amp sound as the KPA will detect automatically if it's a clean or distorted amp.

    OK, so why are profiles created for Clean, Crunch and Lead? Why not simply create a good Clean profile and let the user dirty it up as he wishes? Is it done simply for convenience (pre-set to crunch or lead so fewer twiddling to do)?


    How can a profile simulate the amp in power tube saturation vs when just using pre-amp distortion? Simply by running the test sounds thru it? How much does the fine-tuning portion of the profiling (where chords are played and picked up thru a miked speaker) contribute to allowing the profile to distinguish pre-amp distortion vs power tube distortion?

    While changing the gain parameter - the KPA increases / decreases the amount of gain - but it may not sound like changing the gain knob on the real amp.


    Think of the KPA's basic amp sound like this:
    Filter1 (Amp) - Distortion Algorithm - Filter2 (Cab)


    During the profile process (and refine) will the parameters for the two filters be defined and stored.
    The KPA also detects the amount of distortion and some other parameters for the internal amp modeling.


    This gives you a great snapshot of your current signal chain - with the current amp settings.


    If you like to get some more gain - just turn the KPA gain knob - you can even get more gain as the real tube amp can produce.
    But this is all you get more/less gain with about the same sound (the two filters will not change by this).


    When changing gain on a real tube amp - you may get a complete different sound - because the frequency response of the amp changes as well.


    This all depends on the tube amp type.


    So to accurate capture the sound of a tube amp we need many profiles for different gain settings.


    The KPA controls can be used to tweak the profile to your liking.


    It's a little bit like sampling in the old times (single vs muli samples).


    It may be the next generation of profilers where multiple sets of filters can be stored and extrapolated to fit the real amp.
    In this case we would need to profile many times (different tone stack and drive settings) and the KPA could capture all this and create an accurate model of each amp.

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    Elvis,


    I'm not sure I'm getting what you write about pre Vs. power amp distortion.
    The Profiler has no way to know if the pre or the power section of the profiled amp are distorting.
    The Profiler asks whether you're creating a clean or distorted profile so that it's able to better recognizing the amp's behaviour and create the profile's file.
    Anyway, increasing the gain in a clean profile will not give you the same sonic result as profiling the amp distorted, because the Profiler has no idea how the clean amp is going to distort until it tests it.

    OK, we're getting there. But in order to capture the rich, full power tube distortion of the reference amp, how does the Kemper accomplish this? To achieve it on the reference amp you'd have to dial up the master volume to 5+ in order to fully engage the power tubes. Are you saying that to capture this on a profile you'd have to set the amp up this way so the Kemper could pick this tone up from the miked speaker cab? And if so, do people understand that this is a requirement in order to capture the very best distortion tone from the amp? Because as we all know, there's a world of difference in quality between pre-amp distortion and power amp distortion.

    again, what you do is to create a snap shot of your amp....


    so let's say you profile an amp with 2 channels, one clean and one distortion...


    then you'd dial in the clean sound you like, find the best mic position and possible add a mic-pre to the mix and profile this clean channel. Once you have your profile of this clean channel you can create variations or dial in a even more precise clone of your tube amp via the amp section controls....save these separately and leave your original profile as basic DNA of your clean channel...


    now you repeat this for your distortion channel, dialing in rhythm and lead tones and profiling these then, fine tuning and again, leave the original profile alone so you can always go back and create a new sound....


    the clean sense and distortion sense will only help you setting up a correct profile but these settings are also smart and know if you are profiling a clean or distorted amp and kind eliminating user mistakes...


    as far as pre-amp and power amp distortion that again can be part of your profiling process and you have to dial in these ideas as well...what I found helpful is to create a spread sheet with the different values for each amp setting that I profile so I can get an idea of the interplay, feel and sound of all these settings. Then fine tune the profile and of course archive the ones i don't like or need...


    Factors in profiling are Channel Volume/ Gain and Master Volume as well as Speaker, Cab size, Mic, Mic Position, room and if you run it through a mic pre amp or blend it with other mics etc...just experiment...


    clear enough? :)

    Quote from elvisscottyandbill

    do people understand that this is a requirement in order to capture the very best distortion tone from the amp? Because as we all know, there's a world of difference in quality between pre-amp distortion and power amp distortion.


    I think so. The proficient profilers dial in the sweet spots for their amps and profile.

    On a side note, I'd not call a profile a "snapshot"; this term evoles a staticity which doen't belong to the concept IMO. A profile is like a model in a ... modeller: starting from it you can use all the machine's controls to shape your sound, exactly like in any other digital device on the market.

    Quote from viabcroce

    On a side note, I'd not call a profile a "snapshot"; this term evoles a staticity which doen't belong to the concept IMO. A profile is like a model in a ... modeller: starting from it you can use all the machine's controls to shape your sound, exactly like in any other digital device on the market.

    Looks like it works, BUT, as far as I’m learning the device, I can definitely see the difference. I prefer to keep knobs very close to <0>. Otherwise there is a big chance to loose THE TONE and character of a real amp. In fact, it is obvious: there is a very big difference in any tube amp behavior from clean, saturated to high gain. Every element of signal chain is involved and behaves differently. Thanks to THE KEMPER, now I can keep so different characters in one box. Probably Kemper is the future trend of digital guitar processing.

    Quote from viabcroce

    On a side note, I'd not call a profile a "snapshot"; this term evoles a staticity which doen't belong to the concept IMO. A profile is like a model in a ... modeller: starting from it you can use all the machine's controls to shape your sound, exactly like in any other digital device on the market.


    Yes. I just wanted to make the point with this thread that one cannot simply set the master volume on a 100 watt amp to 2 (plenty loud on my Masotti X100M) and create a profile of it and then expect to run the Kemper and simply crank up the volume to get richer tube distortion tone. That won't work. How could it? The Kemper never had an opportunity to model that tone. You must dial up the exact tone you want to capture on the reference amp and capture that (be it clean or distorted). Then you can tweak it on the Kemper to your hearts content.

    all these things are to be taking into consideration when profiling. Volume and Gain settings usually influence each other and also the EQ structure and over tone series of amps. I feel that different amp settings that are profiled create totally different amp profile and sound that could not be otherwise dialed in from an all encompassing profile. From my experience profiling many amps now is that it is necessary to dial in different amp settings etc to bring out special characters in your amp that otherwise can not be dialed into a profile alone...

    My experience is the starting profile WILL affect the end result somewhat. But the differences get larger if you use non-standard amps. Like you are trying to profile an Acoustic Preset on a Modeler.


    When I've used a Distortion or Clean amp reference to do an Acoustic Preset on a Modeler, I get less realistic Acoustic Profiles than if I START with an Acoustic Profile.


    But even using regular amp, like the recent Hot Rod Deluxe I did, if I start with a crappy profile I chose for it's particular crappiness, it is NEVER as authentic a profile as when I choose one of my favorite profiles. I do not know why or how, I only know, it DOES matter that you choose a good and similar Reference amp.


    Yell at me if you think I'm wrong, I only have my ears and experience to come to this conclusion. Haven't done a scientific study.


    The way I look at it is: It's in the Instructions. Follow the Instructions.

    Quote from TheLightspeeder

    all these things are to be taking into consideration when profiling. Volume and Gain settings usually influence each other and also the EQ structure and over tone series of amps. I feel that different amp settings that are profiled create totally different amp profile and sound that could not be otherwise dialed in from an all encompassing profile. From my experience profiling many amps now is that it is necessary to dial in different amp settings etc to bring out special characters in your amp that otherwise can not be dialed into a profile alone...


    This!