using Kemper effects straight into front of tube amp

    Quote from dango123

    Thanks, I'll give it a try later today and report back with my findings - appreciate the help with this!

    I continued experimenting - I switched to a different cable profile called "Cable Direct" by PWhe23 in Rig Exchange - after I matched volume levels between the on and off states of the amp module, the drive effects sounded essentially the same whether the amp was in or out of the signal chain. I'm guessing the earlier cable patch profile we were using (LMTTRAY - A-Stick) had some profiled qualities that reacted in unexpected ways when the drives were engaged. All good for me on this point.

    I also re-installed the latest firmware, and continued to experiment with the various drive options via headphones and into a real amp - here are some preliminary findings:

    - the Kemper Drives and Green Scream defaults still have more of that clean signal mixed in and give (me at least) a less familiar tone and feel, although as Christoph mentioned, this gets reduced somewhat as the drive and tone settings are turned up. Perhaps I just need to get more familiar with Kemper Drive options since the presets don't correspond with how I typically use these pedals. Personally, these tones don't feel or sound particularly "right" to me especially going into a real amp (and of course that could just be my own perceptions).

    - For the most part, the drives outside of the Kemper Drive (e.g., Plus DS, One DS, Mouse, Full OC, etc.) have more of the expected feel - not sure if the firmware re-install had something to do with this, but there seems to be an improvement going into the amp which makes me a bit more optimistic. I will continue to experiment, but it feels like I'm moving in the right direction.

    I'll continue to report back as I learn more - huge thanks to everyone that's been following along, and for sharing thoughts to help me work this out, I greatly appreciate it.

    Best,
    Dango

    Quote from dango123

    the drive effects sounded essentially the same whether the amp was in or out of the signal chain. I'm guessing the earlier cable patch profile we were using (LMTTRAY - A-Stick) had some profiled qualities that reacted in unexpected ways when the drives were engaged.

    Edit: see post 49 with the conclusion that this hypothesis is incorrect

    I’ve been going back and forth between trusting / not trusting my ears on this matter for a while,
    but this test result sets in stone to me that there is something going on:
    Drive test2.wav

    1st/2nd chord is the difference as a result of switching the amp off using an analog drive: level reduction only

    3rd/4th chord is switching the same variable (amp on /off), but now using the K drive: level increase, and clearly a very different sound. (>clean path to my ears)

    That’s a clear test result: unmistakably a significant difference switching the same variable, with the levels going the opposite direction, which makes the hypothesis that a clean path is introduced/raised even more plausible then just the observation by ear.
    This makes it incomprehensible why support does not further investigate this…unless they don’t see 4cm as a usecase for the unit.

    Besides that, I want to be able to trust the integrity of the signal path, and concerns with it properly adressed and or explained…but none of it atm.




    *I made a profile of a patchcable for the test (and selected a cab from an earlier one), but that profile is actually irrelevant cause it remains switching 1 variable giving different impact on the end result.

    Edited 5 times, last by Job Posthuma (August 18, 2025 at 11:13 AM).

    Quote from Job Posthuma

    1st/2nd chord is the difference as a result of switching the amp off using an analog drive: level reduction only

    3rd/4th chord is switching the same variable (amp on /off), but now using the K drive: level increase, and clearly a very different sound. (>clean path to my ears)

    That’s a clear test result: unmistakably a significant difference switching the same variable, with the levels going the opposite direction, which makes the hypothesis that a clean path is introduced/raised even more plausible then just the observation by ear.

    I’m not sure I follow your test methodology. Where did the analog drive come into play? What was the signal path in both scenarios? How does this make the clean path hypothesis more plausible?

    Quote from Wheresthedug

    Where did the analog drive come into play?

    I used that for comparison of the effect of switching the amp block off between the 2. I did this to exclude the option that switching the ampblock on/off has an effect that is mistakenly contributed to the Kemperdrive. Now you can compare effect on A to effect on B, which should be similar, but are not. That means something else is happening under the radar.

    Quote from Wheresthedug

    What was the signal path in both scenarios?

    Equal between the 2, albeit the analog drive going into the input of the Kemper. The only variable is the ampblock between 1&2, and also between 3&4.

    Quote from Wheresthedug

    How does this make the clean path hypothesis more plausible?

    Switching the amp off using the analog drive causes a lower output.

    Using the K drive causes a higher output. I did all this cause I hear a clean path is added, adding something is consistent with a level increase.


    All test methods aside, do you also hear more clean signal in the 4th strum in the audio clip in post 42?
    I also hear in the 4th strum, that the level of the driven sound is reduced compared to 3…exactly like between 1 and 2.

    Edited 2 times, last by Job Posthuma (August 12, 2025 at 10:53 AM).

    Quote from Job Posthuma


    All test methods aside, do you also hear more clean signal in the 4th strum in the audio clip in post 42?
    I also hear in the 4th strum, that the level of the driven sound is reduced compared to 3…exactly like between 1 and 2.

    I hear differences but whether that is the clean path that you hypothesis, I'm not sure.

    There are a lot of things going on. First kill all delay and reverb and just listen to the Drive. any discrepancy could be caused in other parts of the signal chain.

    Did you set Amp Volume Compensation to 0?

    There is way more noise in the K Drive strums 3 and 4 than in 1 and 2 so, again, something else is happening which may or may not be attributable to "clean signal". What are the input settings? Noise Gate? Clean Sense? Distortion Sense?

    Is there anything else on in the Kemper signal Chain? What Block is the K Drive In?

    I don't seem to get the same results as you are experiencing so something is different but I don't know what.

    I tried my own test again and recorded a quick example.

    Clean = KPA Direct Out into front input of THD BiValve. Line Out of THD BiValve into MOTU ULMK5. Recorded in Logic with TwoNotes Genome as an IR Loader only.

    I made my own cable profile with Volume Compensation at O and Amp Volume at +12db. Even in this scenario the cable is still slightly quieter than with Amp bypassed but the difference is minimal.

    First take KPA Amp Block Bypassed. Second take KPA Amp Block Active. Thereafter I switched the Amp Block on/off at random. There is a very slight difference which I attribute to the slight level difference.

    Overdriven = As Above but with Full OC loaded at Default settings. Full OC used as this effect type does not have an analog clean signal in the real world so is a better comparison of the amp section hypothesis. Using a TS style pedal which deliberately models a clean signal clouds the comparison as any clean signal anomalies could come from Pedal Model OR Amp Section.

    Again, first take is Amp bypassed. Second has Amp active. Subsequent clips are randomly toggling Amp ON/OFF

    As with clean clips there is a slight volume discrepancy due to the cable profile but I don't hear anything else significant.

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    Thnx for your effort, appreciated! Support is taking the time to look into it now…I’ll hold my breath a bit on the subject for now to not further stir the pot…untill the smoke clears.

    Kemper support investigated and the conclusion is (fortunately), that the audiopath remains integer when switching the ampblock off. My hypothesis that a clean path was added was incorrect.

    The observation of a difference in the testsetup was correct, however the rootcause was the fact that also a profile of a patchcable includes a gain stage, and cause in my test setup the volume of the drive was set at 5, that stage clipped, which explains the different lvl of cleans in the observation, but is “as designed” and not an issue for use in 4cm and or in front of an amp.

    Repeating the test without clipping the gainstage resulted in equal results, which confirms the integrity of the audiopath.

    Edited once, last by Job Posthuma (August 18, 2025 at 11:14 AM).

    • Official Post
    Quote from dango123

    Thanks again for weighing in on this point - I will say that the bit shaping pedals that I've worked with, like the EQD Bit Commander, have a more extreme impact on the sound. The test example I provided in my earlier post resulted in an extremely subtle effect which didn't seem like it added much; I did play around with the Drive and Tone settings during my initial experiments but it didn't seem to do much - I will revisit this to see if it makes much of a difference.

    Best,
    Dango

    Hi!

    Another aftermath: The EQD Bit Commander is not a bit shaper at all, but merely a sort of synthesizer/octaver. Different sound.

    CK

    Quote from ckemper

    Hi!

    Another aftermath: The EQD Bit Commander is not a bit shaper at all, but merely a sort of synthesizer/octaver. Different sound.

    CK

    Wow, thanks for the follow-up, I really appreciate the clarification.

    Incidentally, the Bit Commander is a SMOKING effect pedal, would be awesome to see a model of this one showing up in Kemper one day... ;)

    Thanks again,
    Dango