Experiment (failed) profiling realistically a bulk guitar head

  • Hi everyone. I want share and ask suggestion for an interesting try i made on late days. I tried a quick search on the forum for see if this question was yet made without results, so forgive me if this a sort of double post of a similar discussion.


    After a abundant year with my Kemper Amp and a full range usage, i'm doing some trying with real guitar cabs and solid state amplification. Results is very good indeed, but i notice (i noticed even a year ago, but it was not searching in that direction) a missing part in overtone and harmonics.


    So i did this experiment. I profile a guitar head (a Cicognani Brutus, a modern sounding italian tube amp) with a di box without cab. The Kemper Amp can profile the whole chain, and you can turn off even the cab, but how be sure or "measure" if the amp alone is profiled in a right way? My suppose was than if i can reproduce the di box tone, with a good linear power stage i can afford a very similar head reaction.


    The result (better avoid long posts with my horrible english!) is no. The overall very high range of harmonics (those who kill your ears) of a direct head profiled without cab cannot be profiled. I tried to re equalize, various try, various volumes. But this part of frequencies in the profiled amp are missing, and this make sense as even without headphone i can distinguish in my guitar cab the Kemper Amp and was darker and empty on the harmonics side. Obviously i tried before a common profiling with a cab connected to the head, and turning off the cab i miss the same harmonics i'm talking about.


    I find even some strange behavior (you can turn off cab or amp in the reference amp tone? how i can turn off something in an external real amp??). But the final meaning of my try was: can i simply have a valid substitution of an head not for record (this is out of doubt, the Kemper can achieve any micced tone in a great way) but for "in your face" usage? I'm not really interested at all to make a Vox play like a Dual Rectifier, this is acoustically not possible, but my question (and need) is if i can realistically can substitute with Kemper + linear amp a real head for use with a cab.


    I'm very curios to read your opinions and your suggestions, or if someone has tried and maybe solved (i'm doing something wrong?) this need or is someway this feature is planned as a future feature (the no cab profiling, maybe in the same screen of distorted-clean profiling screen).


    Bye!

  • I've read several reports of successful profiling of DI tone - there are a number of presets in the rig exchange of DI signals.
    Are you sure you profiled correctly?


    It's often said that the art of mic'ing a cab is making it sound like there are no microphones involved -
    most of the users who have submitted profiles aren't as thorough or lack the equipment, but it is technically possible to produce an 'in your face' sound, as you say, with microphones.

    "But dignity is difficult to maintain
    stamina requires constant upkeep
    repetition is boring
    and you pay for grace."

  • I think to profiled correctly the amp, with mics i ever reach total satisfying results in profiling with 100% of the tone here. I saw some di box profiles, but my actual goal is to have the tone of the amp without a cab to obtain same (or similiar, i understand there are difference in any kind of tube or solid power amp) result with the same cab i used with real amp. The frequencies i am talking about are very very high, higher than the presence i can add in the Kemper equalization. But this buzzing with my Alnico Blue make a big difference in overtones i ear. And i can notice a missing on this frequencies even in the other profile than are stunning with cab on used with the cab turned off (and are still stunning with real cab, just darker). Anyone has tried an a/b comparation with his real head and real cab using a powered kemper on that cab?


    I'm thinking if necessary (i need some time) to record in mixer the reference real amp, the profiling and the result and post here. Maybe (i hope, i really want this feature!) i'm doing something wrong or something is not working as it should. But it seem like a sort of filter for noise focused on frequencies than a miced electrical guitar should not play stop Kemper from reproduce on the amp stage all the harmonics and buzz.

  • Normally, taking a DI profile works pretty well. Did you perhaps a DI box with a built-in speaker emulation and forgot to turn it off?


    If you really think that the KPA doesnt capture your DI signal correcty just use the A/B comparison between the original signal and the profiled signal when you are in the profiling mode. Just record both signals with your DAW and use a good spectrum analyzer to see if there are any differences.

  • Sure, i turned off the cab emulation. But this is not a problem, even playing during the profiling process the signal from reference amp remain totally different from the profiled one so the "problem" is after the profiling process, not in the di capturing. I used before the Kemper Amp a lot real heads with software cab emulation for recording, so i've an idea on how should work the whole part. The spectrum analyzer it's an idea, but even by ears it's not a light difference, it's huge how many harmonics are missing. Huge on headphones into Kemper Amp, huge listening in a real cab.


    I repeat the question (it's complicate explain in english, this can be an easy way to understand what i'm trying to do). Someone has profiled his real head and used a powered Kemper Amp on a guitar cab, and can say no difference or minimal difference bethween drive the cab with the tube amp and with the powered Kemper?


    I'm not arguing if i can obtain great tones with a guitar cab, but if a powered Kemper Amp can reproduce exactly the tone of my head into my cab. At the moment i would say "no" and i would LOVE to do this.

  • Someone has profiled his real head and used a powered Kemper Amp on a guitar cab, and can say no difference or minimal difference bethween drive the cab with the tube amp and with the powered Kemper?

    Yes, taking a DI profile oj my JVM and playing it back through a sold state amp into a guitar cab can result in nearly perfect match, making it sound almost exactly the same as the original amp.

  • I tried to refine and refine, but those high harmonics buzzing won't appear. I tried to cut of the presence and high before profile for increase after profiling. In my mind i tried everything, but if you reach to obtain same tone of your bulk amp something is wrong or missing.


    I'll try to do an audio record of the whole procedure so you can listen (maybe compression cut off lot of articulation, but i'm quite sure the difference is to big). Maybe i can post also the file of the profile. I forgot to mention my firmware, i've the 1.7.0, but i've a remind of that fact a year ago with an older firmware (at time i noticed but i was not trying to use like an head for a guitar cab)

  • You can re-amp a clean signal and record through both during the profiling phase itself, that's really the only way to get a signal that's really viable to compare (unless there's dramatic differences in tone), as the alternative (plugging into the amp recording a riff, then plugging into the Kemper and recording a riff) results in changes due to impedence differences of the inputs, something which as far as I can tell the Kemper doesn't seek to emulate. And each time you play you get a different performance.


    I also notice that personally my own playing is slightly different between playing through the profile of an amp and playing through the real amp and when playing through the amp even during the profiling to me it always feels more lively and clearer/complex at the high end, as good as the Kemper is it's never quite as fluid and feels more compressed, I put that down to the latency affecting how I'm playing, because as soon as i have a re-amped track that i can hear side by side instead of me playing through the differences are usually much smaller than i felt (so unlike most I don't feel that the Kemper nails the feel of a tube amp, just the sound).


  • If I am understanding your post, I had EXACTLY the same problem. I found that the KPA did not do a satisfactory job of profiling DI amps IMO. I even posted sound clips and images of the frequency response curve to show that I was not imagining the results. CK said that profiling DI produced the same excellent results that you would get by profiling an entire rig, but my ears and eyes beg to differ. I never really found a solution.


    My post was entitled: "My findings using the KPA as a DI solution"...specifically check out the images on post #15. The frequency response chart shows the same high end cutoff that you are talking about.


    Here's the link:
    My findings using the KPA as a DI solution

  • Woah. I made some try and i find some strange stuff. I post the files here.


    Test 1: my head on dibox and no cab emulation into mixer, direct recorded here


    Test 2: my head on dibox into Kemper Amp in reference mode with the cabinet button ON (the fact i can leave off a cabinet for an external source it is weird, but results active by default profiling mode) here


    Test 3: my profiled tone after a deep refining and with cabinet turned off here


    Test 4: my head on dibox into Kemper Amp return with the cabinet button OFF here


    The result is weird, and for this reason i made all that confusion. Let's go in order with my impressions:


    Test 1: i'm not sure it's a perfect tone, but the dibox is active so it should correct the impedance (i used in past even to correct the passive pickup signal before the audio card with good results). Is quite bright signal as you can listen.


    Test 2: unexpected. The reference amp in profile mode is darker, not very much but is quite audible. So the amp that should represent the original tone seem not as good as the tone into the mixer. The cabinet button is on by default.


    Test 3: the profiled amp with the cabinet on is much darker (is some a virtual cab is in some way added during profiling) but turning off the cabinet, it lightly less brilliant than the Test 2 tone but more or less, quite similar. Still darker than previous test and far from Test 1.


    Test 4: if you turn off the cabinet button from the reference amp in the profile mode, so from the external amp (how you can turn off the cab in an external amp??), the tone became absolutely bright and fuzzy with ton of harmonics. I intended this tone as the "regular" tone from the head in previous post and tries, but after listening the mixer one i'm not so certain.


    What i'm quite certain is than on the guitar cab, i felt the difference and is quite huge. I'm in doubt now if the real tone of the head is the totally harsh (but very rich in harmonics) Test 4 with reference amp into Kemper with cabinet off, or Test 1 into the mixer. I'm trending to image the Test 4 is the closest because is way far the brighter and the difference i can listen in the real cab is huge.


    Sorry if i'm unclear, it is a quite complex things to say (and my english is not good). Maybe with your contribute i can understand better, or we can find a closest interpretation of the result of those tests. Thank you again for your replies. mp3 has some loss from uncompressed tone, but more or less i think the difference bethween tests can be easily listened.

  • Only some thoughts,
    the KPA stores the profiling results always into the amp AND cab block.
    This is independent of the source (amp&cab, only amp, other stuff).


    So even when you profile an amp without a cab - the KPA's cab block must be activated to get the same sound.

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  • If the cabinet block in the profiled bulk amp is active, the tone is totally different and much darker like a sort of default cab is added. The similiar tone are from the reference amp WITH the cab on (Test 2) and the profiled amp with the cab off (Test 3). I spend the night thinking on it. The better tone in Test 1 from Test 2 can be caused for some factors, as in first case the dibox is directly into mixer and in the second that make lot of routing before go into mixer (and it take another AD/DA conversion), anyway the difference is not huge.


    I will do a try today or when i find time to do. I'll try this routing:


    my tube head - dibox (routed into a mute cab i used in past for silent recording) - solid state amp - guitar cab


    I want to understand if this tone is also much worst than the tube one (so Kemper Amp is innocent and do a good job), or is quite better than the profiled one. I've some other tries in mind. I want also do a comparision bethween a tone from a cab leaving the cabinet in a second time, and the tone profiled directly without cab. How good is the cab removing? The tone profiled with a full chain used without cab are still realistic?


    Maybe the usage as an amp head is a quite new role for the Kemper Amp (the powered version is recent) so we can expect further improvement.

  • Please do not turn the cabinet off while profiling or comparing. The cabinet part is needed, even when it's a direct profile.


    In the future we will have methods to make a distinction between a direct profile and a regular profile (still this would not change the sound, but improve the handling)

  • Question, where is the idea with the linear poweramp from? I got better results with a tube poweramp and a cab. Yes, you could say it's a bit double colouring but if it sounds good it's good. When a part of the amps sound is baked-in in the cab part, then you kill some poweramp influence by turning the cab off. By using a tube poweramp you get it back. BTW, you will always hear what you use to make your signal loud, even the linear poweramps have their own voice, how else could it be that there is a hype for certain stuff like the matrix amps. How could a matrix poweramp be better when everything linear is the same? Many claim that their product is linear, non colouring, not distorting. Can that be true?

  • Question, where is the idea with the linear poweramp from? I got better results with a tube poweramp and a cab. Yes, you could say it's a bit double colouring but if it sounds good it's good. When a part of the amps sound is baked-in in the cab part, then you kill some poweramp influence by turning the cab off. By using a tube poweramp you get it back. BTW, you will always hear what you use to make your signal loud, even the linear poweramps have their own voice, how else could it be that there is a hype for certain stuff like the matrix amps. How could a matrix poweramp be better when everything linear is the same? Many claim that their product is linear, non colouring, not distorting. Can that be true?


    The question, which has not been answered to date, is whether or not there is any sort of dynamics processing in the cab section of the KPA.
    If so, you're right. If not, the amp section takes care of the PA emulations and you'll just need something linear.
    Regardless, a tube amp at higher volumes will compress your profiles, meaning you'll get a dishonest representation of your sound - which will change everything from saturation to sustain to EQ.
    A tube amp at lower volumes will sound like a solid state PA, apart from damping which is the dynamics processing issue.
    All in all, i'd go SS and to FOH - but these are my needs and for a bedroom warrior i'm not sure that's important.


    As for linearity - while nothing (to date, anyway) is truly linear, a linear product's purpose is to come close and be controllable. This is successful to varying degrees - which is why the hype is there.
    Other than that there are other aspects - weight, reliability, volume, heat, functionality etc. which would also explain the hype.

    "But dignity is difficult to maintain
    stamina requires constant upkeep
    repetition is boring
    and you pay for grace."

  • Poeple that play tube amps with their effects in the loop always have their effects compressed and coloured of the poweramp. Reverbs of guitaramps are usually coloured, all normal.

  • Poeple that play tube amps with their effects in the loop always have their effects compressed and coloured of the poweramp. Reverbs of guitaramps are usually coloured, all normal.


    I don't think i get you. If i do, i can't see how this is relevant...
    Your reverbs and effects in the loop don't go to the FOH, so what you hear is what they hear is what gets recorded.
    Not so with the KPA.

    "But dignity is difficult to maintain
    stamina requires constant upkeep
    repetition is boring
    and you pay for grace."