[Public Beta] PROFILER OS 8.0.0.21450

  • When you turn the drive knob up on the Klon, the main clean signal path is also blended out by getting shunted to virtual ground. It definitely becomes a hard clipper as you turn the drive up. I'm sure you know this so I don't know what the disagreement is here.


    Does the Kemper Drive exhibit a hard clipping behavior at the high/max drive Klon preset settings?

    What does the Slim Down parameter do exactly? Is it simply a boost around 1 kHz?

    No, it does not become a hard clipper, because there is a second parallel clean path that stays, because it is not affected by the drive pot.

    Named "Network 1" in the electrosmash analysis. And it can easily be heard in the Klon's output.


    Btw. the term hard clipper and soft clipper is a bit misleading as used in the Strymon analysis.

    Soft clipper is usually the name for a "soft knee" distortion, not for a distortion with a parallel clean path.


    Slim Down narrows down the frequency responce around the "Definition" frequency, wherever it's set.

  • It is not true that DSP is mostly done in the frequency domain.

    The Kemper Drive is build like an analog circuit.

    Calculations are usually done in the time or frequency domain, whatever serves best. Same as in the analog world.


    The Z - Transform is just a little wheel in the hole game.

    ... and I would be a fool to disagree ;).


    Then my guess would be the analog model is more sophisticated than any one of the simple circuits found on the stomps it is able to model. It was an easier guess to assume you modeled it in the frequency domain to create a transfer function that is able to cover the result of a range of stomps.


    That will teach me to 2nd guess the guy that designed the device ;).


    How something is implemented is less important than the users end result..... easy to get to a sound you love, and sounds good.

  • The second clean path is low-passed at 100 Hz and goes to add some bass to the final output. The clipping characteristic for most of the freq spectrum is unchanged by the second clean path. Running a SPICE sim for sanity check, and removing the second clean path does very little to change the shape of the clipping above the bass freqs.


    In the diode clipping pedal world, it seems that's how these terms are used. I agree it's misleading and makes the convo unclear, I could've chosen my words better.


    Thanks for the clarification on the Slim Down parameter, and actually clarified the Definition parameter for me as well.

  • The second clean path is low-passed at 100 Hz and goes to add some bass to the final output. The clipping characteristic for most of the freq spectrum is unchanged by the second clean path. Running a SPICE sim for sanity check, and removing the second clean path does very little to change the shape of the clipping above the bass freqs.

    That's true.

    But can you make valuable assumptions by looking at a distortion shape, that is generated using a parallel clean path?

    I don't dare it.

    We usually analyse first, to understand the overall architecture. Then we always finalize by ear.

  • In the end, the ear is all that matters.


    For me, looking at 2 time based signals is very difficult to "see" what I can hear easily. Looking at an FFT of the same signal is better, but even then, it is just crazy at how sensitive your ears are to a combination of minute differences in a signal.


    A good ear is worth 100 scopes and all the algorithms in MATLAB ;)

  • This seems to suggest that Kemper took the approach of providing the soft clipping options in the Kemper Drive and the Hard Clipping in the Full OD. In which case, why would you need to add hard clipping to the Kemper Drive?

    I am not sure if that was the approach, specially looking at the Klon presets of the Kemper Drive.


    Based on circuit soft/hard clipping design. according to Josh’s video. (9:06) above, Klon is not part of the 808 family, it is a unique type of hard clipper overdrive when you set the gain knob above 60%, and below that gain level it is just like a “fancy boost”, he says. CK says more or less the same by remarking that by turning down the Klon’s gain then the distorted path is blended out to create a clean boost. So, if Josh is right, Kemper Drive Klon presets 1, 2, 3 are related to the Klon hard clipping.


    @CK comments suggest that the distinction he made between the Kemper Drive and Full OC is not about clipping but how the clean signal is mixed to the distorted signal. So, by this approach Klon is an OD and Full OC is it’s own distortion family.


    The difference is simply, that on overdrive pedals only, a good portion of the clean signal (undistorted, uncompressed) is mixed to the distorted signal, preserving some uncompressed playing dynamics in parallel to the distortion.

  • That's true.

    But can you make valuable assumptions by looking at a distortion shape, that is generated using a parallel clean path?

    I don't dare it.

    We usually analyse first, to understand the overall architecture. Then we always finalize by ear.

    I have met tech nerds who sat for weeks in front of schematics and shapes building their "dream amp"..none of them understood what went wrong afterwards..


    Interesting to hear that it is the very same even with OD pedals.


    "By ear" seems to have become a very strange concept in music lately(last 20 years)..

  • we should all say thank you Kemper team for these two excellent sounding drives,

    no matter if they sound like this or that,

    the truth is they sound great! and that is more than enough

    Thanks for that

  • Some Jackson Audio products change clipping configurations while compensating for the change in clipping-threshold/headroom. You can go check out some demos. Is it a subtle difference? Yes but it is audible and perceivable IME.

    Do you have a video where they demonstrate it in a more analytical way?

    I only find quite superficial examples, as so often.


    During our research we found that different diode configurations might have influence on the surrounding circuitry, moving the mid bump up or down. This is not a proven fact. However, the KD‘s mid bump can be varied by the Definition control anyway, so we did not care too much about the dependencies. The differences in the harmonic content is less of a feature and vastly overrated. The stories about this are pure marketing and/or unknowingness even by the makers, in my perception.


    I have always tried to bring sonic effects down to the essencial and to be honest to our users.


    In a way we have a litte empirical study running since 10 years in the Profiler. In the AMP section we have the well known parameters Tube Shape - widely varying the distortion curve - and Tube Bias - controlling the assymetry of the amp distortion in an extremely wide range.

    We did, however, NOT market these parameters as crucial keys to achieve a better tone, as we felt that the impact is very limited. Still the parameters are freely accessible since day one.

    You might be aware, that no single Profiler player has ever discovered these parameters by himself and identified them as a true sonical innovation over tube amps, and a crucial tool for the search of your individual tone.

    Have you tried them?


    To me this is a proof that diode configurations in ODs are highly overrated.

  • Here a video of Kemper Drive Vs. Real pedal.

    It is in italian, but i think is clear how good Kemper's work is.

    https://youtu.be/Q8UfEuKs4Lo

    Very good video, first listened just on my iPad Pro speakers but was intrigued enough to hook up my DAC and AKG 702’s for a closer listen. Obviously there were small variables in volume level and the demonstrators ear to match but he seemed pretty good, really impressive for the KPA overall.

    New talent management advice to Laura Cox -


    “Laura want to break the internet? let’s shoot another video of you covering the Nightrain solo in the blue singlet, but this time we’ll crank up the air conditioning”.

  • You might be aware, that no single Profiler player has ever discovered these parameters by himself and identified them as a true sonical innovation over tube amps, and a crucial tool for the search of your individual tone.

    Have you tried them?


    To me this is a proof that diode configurations in ODs are highly overrated.

    For your information, I use both of them frequently :D (and Power Sagging even more). Thank you for putting those controls in the Profiler.

  • I tried to replicate the Kemper Drive Klon 4 preset using my Ceriatone Centura pedal and in the beginning I really struggled. Here's what I did and found:


    1. I used a custom made profile of my Tube Thomsen Defcon-7 (a VERY rare amp and I have serial #1) ... Gain on the Profiler is 5.5, profiled through a 4x12 with Greenbacks using Neumann TLM 49 and Beyerdynamic M160.
    2. Kemper Drive is in slot A and the Ceriatone Centura is in slot B using Loop Mono ... no other slots used
    3. When I switched back and forth with the Klon 4 preset and the suggested settings for a Klon pedal, they sounded VERY different, I mean VERY VERY different. Quite disapponting moment, to be honest.
    4. After some more testing and analyzing, I found out that it just doesn't work at all with the Kemper Drive's Volume set to default <0.0>. The Kemper Drive didn't push the amp even remotely the same like my Ceriatone Centura (with Output set to 3 o'clock).
    5. When I turned down the Centura's output (roughly 8 o'clock) to level match with the Kemper Drive, the sound was totally different.
    6. And then I basically did the opposite, turned the Centura back up to 3 o'clock Output and the Kemper Drive's Volume to +5dB maximum
    7. HOLY CRAP ... they are completely undistinguishable, couldn't almost believe it and even ran REW with a sine sweep to check frequency response and distortion characteristics. Frequency response is dead on same, for distortion characteristics, Fundamentals and THD are a perfect match! WOW!


    The only thing I wonder is the following:

    The distortion in the odd harmonics (3,5,7,9) is pretty much a perfect match between Kemper Drive and Ceriatone Centura.

    But the even harmonics (2,4,6,8) look very different (see attached pictures). Especially in the low frequencies and the bump at around 1kHz. Hmmmm.

  • Quote

    The differences in the harmonic content is less of a feature and vastly overrated. The stories about this are pure marketing and/or unknowingness even by the makers, in my perception.

    @CK

    Well..I did not expected you (or any other gear developer) to use such clear words..but thank you..be aware that you will be quoted on this issue from here on..

  • When you push a profile, more of what you’re hearing is the “amp” rather than the pedal.


    For comparison’s sake, I’d be more interested to tone match with the Stack off first. Then add the pedal and see how it shakes out.

  • For comparison’s sake, I’d be more interested to tone match with the Stack off first.

    And that's exactly what doesn't work the way you expect. ;)

    With the Stack off, the sounds of Kemper Drive vs. the Ceriatone Centura massively differ. But once I engage the Stack they are a match. Tried it one more time ... this time with a custom made profile of a 1982 Marshall JCM 800 Bass Series. Gain of the profile is at 2.3 ... this amp is a pretty clean amp with plenty of headroom.

    The result is almost the same like with the Tube Thomsen I used before ... almost. I'd just need 2.8dB more volume from the Kemper Drive Volume which is already set to +5dB maximum. When I add these 2.8dB in the AMPLIFIER block, then it's a perfect match again.


    So to me it seems like at least in my case with the Ceriatone Centura, I would need more output volume of the Kemper Drive than the max +5dB available.

  • No, I don't have a great video of it. It's subtle but I've heard the difference in my experience though, that's all I can say.


    Thanks for expounding your position. Your approach for bringing down effects to their essential is appreciated as it makes them a pleasure to use.


    I'll check out the Tube Shape and Bias controls. But even your manual says there is indeed a subtle difference when you change the Tube-Bias/clipping-asymmetry, which has been my exact position this whole time. Whether this subtle change is overrated or not is a matter of opinion of course.

  • As dickjonesify said, when you push the amp, you're mainly hearing its characteristic rather than the pedal's.