Power amp ONLY profiles?

  • I am pretty sure, you can profile the power amp very easy like a normal direct profile, only using effects loop return instead connecting kemper send to amp input. Of course a di-box between speaker out and cab is needed to get the signal back to Kemper return.


    So same setup as making direct profiles of an amp, but bypassing the preamp. Kemper should capture the flavour, saturation and character correctly.

  • Exactly, it's quite simple, instead of plugging in the front input of the amp, you plug in the Return of the FX loop of the amp and you treat it exactly like a direct profile.


    There's actually nothing to do with the amp EQ because they no longer work as on almost all amps they're tied to the pre amp and you're tapping the signal bypassing the Preamp. Not sure if the amp volume will still work.


    So guitar> Kemper Front input to help set levels then Kemper send to TUBE AMP FX lOOP Return. Speaker out into DI to Kemper return.

  • Exactly, it's quite simple, instead of plugging in the front input of the amp, you plug in the Return of the FX loop of the amp and you treat it exactly like a direct profile.


    There's actually nothing to do with the amp EQ because they no longer work as on almost all amps they're tied to the pre amp and you're tapping the signal bypassing the Preamp. Not sure if the amp volume will still work.


    So guitar> Kemper Front input to help set levels then Kemper send to TUBE AMP FX lOOP Return. Speaker out into DI to Kemper return.

    Thanks for sharing the HT-5 power amp profile - still using it!


    I hope others are encouraged and will try it out with what they have at hand ... and share there power amp profiles :thumbup:

  • I've been thinking of this as well and found this old thread.

    I'm surprised so many people commenting didn't seem to understand what the OP was asking for or saying how difficult it would be to do.


    It seems an easy way to do this would be to run as follows:

    Kemper Out --> mixing board (for send/drive level control to push the tubes into distortion) --> Amp Loop Return -->

    From here, several options... Two Notes Torpedo Live (direct only, no cab!), Power Soak/Direct Box, etc -->

    Kemper Return for profiling.


    I think this should produce a really great profile of output tube distortion.

    I'd love to have some Marshall's, Vox, Fenders profiled this way.

    In theory, you should then be able to control how the profile clips by how hard you drive it (using the profiler gain control) and at which frequencies (using EQ). I can imagine slapping a Tube Screamer, MXR Distortion+, Big Muff, etc in a pedal slot for a classic setup. Maybe throw in a cocked wah or 6 band EQ for the classic Boston/REO/Van Halen tone.


    If you have 2 Kempers you could set one up of just the amp's preamp DI profile and then run that to the input of the other Kemper with just the output amp profile. And I keep saying it, but if Kemper wanted to offer dual profiles, this would be a GREAT configuration option (as well as the obvious parallel option).


    This just seems like such a no-brainer to me.

    For all the cork sniffers always talking about how great tube amps sound compared to solid states, why does everyone profile their amps preamps section and ignore the poweramp stage? It makes no sense to me.


    Thoughts?

  • The overwhelming majority of Profiles (Studio, Merged, and Direct Amplifier types) do include the power amp.


    Direct Preamplifier Profiles are the only type that do not icude the power amp, and there are relatively few of those.


    Exactly!


    Notwithstanding the practical possibility of profiling only the power stage...


    I am not even sure why someone would want to profile only the clipping/distortion of a tube amp's power stage. I am pretty sure, approximately zero musicians and music lovers have heard the sound of (for example) only the 4 EL-34s/6550s and output section of a Marshall 1959SLP, being unnaturally (artificially) sent into clipping. Unnaturally -- meaning that the signal would not contain the all important contributions of the dual triode preamp tubes (12AX7s) and cathode follower, tone stack, phase inverter, etc...you know, all those critical tone generators, shapers and filters which make a Marshall sound like,... well, a Marshall guitar amp.

    Substitute any make/model in this example.

  • The overwhelming majority of Profiles (Studio, Merged, and Direct Amplifier types) do include the power amp.


    Direct Preamplifier Profiles are the only type that do not icude the power amp, and there are relatively few of those.

    Include, yes. But it seems most are relying on primarily the preamp stage for the distortion for the profiles.

  • Include, yes. But it seems most are relying on primarily the preamp stage for the distortion for the profiles.

    That depends on the amplifier profiled, and the amp settings used by the person doing the profiling.


    But, even with vintage amps (with no master volume control) the only way to get power amp distortion is to use a large amount of preamp output. and, those input circuit designs tend to distort when the preamp is turned up.

  • I am not even sure why someone would want to profile only the clipping/distortion of a tube amp's power stage. I am pretty sure, approximately zero musicians and music lovers have heard the sound of (for example) only the 4 EL-34s/6550s and output section of a Marshall 1959SLP, being unnaturally (artificially) sent into clipping. Unnaturally -- meaning that the signal would not contain the all important contributions of the dual triode preamp tubes (12AX7s) and cathode follower, tone stack, phase inverter, etc...you know, all those critical tone generators, shapers and filters which make a Marshall sound like,... well, a Marshall guitar amp.

    Substitute any make/model in this example.

    The point is to to be able to control how much clipping comes from the output poweramp tubes vs how much comes from the preamp tubes and to be able to blend them as desired.


    I feel like I'm in the twilight zone even having to explain this.


    Legend tells it that poweramp tube distortion is the most desireable sounding and the whole reason why tube amps sound so much better when driven hard than solid state amps. Hell, Marshall sells (or used to) just the EL34 poweramp section alone for people who wanted to get this sound.


    And yet you are arguing that no, it's the preamp tubes, tones stack and phase inverter that makes a Marshall sound like a Marshall, and no one should care about the distortion coming from the poweramp tubes. Might as well just use a clean solid state amp.


    I know that's not what you mean... and of course I get what you are saying about the pre components. It just seems odd that you would dismiss what I'm trying to say about the output tube distortion and wanting to be able to dial it in independently of the preamp side. The point isn't to eliminate the preamp side, but to separate the profiles to be able to better control where the clipping is coming from, especially since the Kemper doesn't do well when profiling multiple gain stages in series.


    Not sure why it's so difficult to see the benefits if what I'm suggesting.

  • Hello Bob,


    I am not arguing. Nor am I being cheeky or sarcastic. Indeed, you have put forth a valid possibility in profiling. However, I think, perhaps, you are putting too much stock into the sonic characteristics of a tube amp's output stage. The output tubes are meant to cleanly amplify the input signal. Yes, the output tubes of a tube guitar amp can be coaxed into soft-clipping. However, the results of the output tube clipping characteristics cannot be separated from the input (feed) signal. Mostly, the effect of the output tubes is in how the amplified signal, sent to a guitar speaker, "feels" and reacts...rather than sounds...to a first approximation. In any case, the issue is rather moot...in the sense that in your scenario, the profiler would be capturing the primary essence of the Mixer signal, being amplified and perhaps clipping the output stage. It will NOT sound like a guitar amp, because the notional Mixer does not have the preamp section of a guitar amp. I mean, it will sound like something...but probably nothing you would be interested in playing.


    Nevertheless, it might be an interesting experiment, and who knows, it might produce something musically useful for the guitarist. Never know until it is tried, I suppose. :)


    Cheers,

    John

  • That depends on the amplifier profiled, and the amp settings used by the person doing the profiling.


    But, even with vintage amps (with no master volume control) the only way to get power amp distortion is to use a large amount of preamp output. and, those input circuit designs tend to distort when the preamp is turned up.

    Exactly my point!

    So how much distortion is really coming from the preamp and how much is from the power tubes? It's hard to tell because the Kemper itself can't really tell. But if you profiled them independently, now you can control it better and dial in what you want from where you want it.


    I had a similar problem when I tried to profile my Rockman Ultimatum preamp because it has 2 gain stages in series parallel. (Positive voltage is distorted separately from negative voltage and they are distorted for different frequencies). The Kemper didn't do a good job with that either.

  • I made a profile of the power amp of my Koch Studiotone. That sounds pretty good in combination with a preamp pedal like a Victory V4.


    Next, I will do a direct profile of the power amp of my Dirty Shirley.

    Make sure you can control the signal level going into the poweramp from the Kemper so you can drive it into good distortion.


    If you do, then you should be able to set the distortion level of the power stage you profiled with the gain control of the Kemper. You should also be able to control the frequencies that are distorted by EQ'ing the signal you send it from your preamp.

  • I made a profile of the power amp of my Koch Studiotone. That sounds pretty good in combination with a preamp pedal like a Victory V4.


    Next, I will do a direct profile of the power amp of my Dirty Shirley.

    Hello Workingtitle,


    Just curious...what did the profile sound like, on its own, with no external preamp or stomps, and no addition of internal Kemper stomps (i.e., A, B, C, D all off)?

  • Just curious...what did the profile sound like, on its own, with no external preamp or stomps, and no addition of internal Kemper stomps (i.e., A, B, C, D all off)?

    It sounds a little lifeless and flat alone. But in combination with the Victory V4 Preamp it becomes something.


    So far I've only done one profile. The Studiotone has an unfiltered direct out, which sits behind the power amp. So it's pretty easy to make a profile from the power amp.


    How the profiles of the Dirty Shirley power amp will be, will be exciting. I always liked the preamp pedals best with the power amp of this amp.

  • I'll run a profile through my effects loop on my Uberschall and upload it to the exchange, I'll let you guys know when it's done, this will be accomplished using the Radial Headload and pull from the pre-eq output. That should provide as close to zero color as I can come for capturing the power amp only.

  • I am new here but wouldn't you know, this would be the first thread I go to :)

    I have a little experience with tube power amps. I can't and will not say the name but, I own a website that sells IRs that have loads of them made with different tube power amps as well as SS.

    A tube power amp, depending on what model of amp, can be as much as maybe 50% of the tone of the amp. Every tube power amp or power amp section of an amp is different. They each have their own character. Some add huge amounts of mojo while others (like Mesa) do very little.

    Making IRs with tube amps and capturing that character is a bit tricky. We spent countless hours on getting it right. Lots of trial and error. We even did amps with different tubes and it is possible to hear, although you have to have a very discerning ear, but afterwards decided it may just be overkill and we ditched that idea.

    Concerning the Kemper and capturing just the tube power amp section to me sounds intriguing. My guesstimate would be that 6L6 types would not be as good but EL34 and EL84 might be interesting.

  • A tube power amp, depending on what model of amp, can be as much as maybe 50% of the tone of the amp. Every tube power amp or power amp section of an amp is different. They each have their own character. Some add huge amounts of mojo while others (like Mesa) do very little.

    ...

    Concerning the Kemper and capturing just the tube power amp section to me sounds intriguing. My guesstimate would be that 6L6 types would not be as good but EL34 and EL84 might be interesting.

    Thank you for understanding what I've been trying to say!


    I get a kick out of the cork sniffers who go on and on about how great tube amps are, and then have the master volume set at 2. Or better yet, throw a Digitech, Line 6 or some other floorboard in front of it and get all their distortion from there. It's like, what's the point? You might as well just show up with a solid state power amp (not that there's anything wrong with that). Just saying, if you aren't driving the tube power amp, then it isn't doing much, if anything, for your tone.


    Of course, the problem then is the volume that comes with driving it so hard. But if you profiled it, you could get that tone without having to deal with the volume.


    And as I said, if you had 2 Kemper's, one for the preamp and one for the power amp (or had the ability to have 2 profiles in the Kemper), then you could really make it behave like a real amp would, with the ability to get your tone (and clipping) from both stages, as you would from a real amp.


    BTW, this isn't a knock on the Kemper as it now is. It already sounds very realistic and responds like a real amp. I'm just suggesting that this would bring it to a whole new level of accuracy and flexibility.

  • Yeah, I get it!

    I spent many of years using mostly tube preamps into power amps of all kinds. I've used different SS as well as tube power amps and heads as power amps. Let alone the "feel", a power amp definitely imparts a frequency response to your tone. One of the best ways to understand this is to get a Marshall DSL and a Mesa Rectifier. Try each amps preamp into the other amps FX return. You will real quickly find out which power amp sounds anemic. Hint: it's not the DSL.