Higain amp profiling - hit or miss

    hey there,

    i just wanted to share my experience and observations of profiling a few different higain amps. since i've been profiling through my isocab and using studio headphones for almost a year know, i've got quite used to hearing the kemper as well different amps.

    in general, it seems that the soldano family of circuits is what can be profiled most accurately by the kemper. i used to own a 92 hotrod 50, and now still have my SLO100 clone and a dual rectifier (it's 90% SLO after all). the distortion 'character' of these amps seems to be profiled quite accurately by the kemper when not using too much gain. all in all, there always seems to be a slight loss in bass/low-mids in the kemper as well as some 'air' that gets lost. both things can be adjusted afterwards and would become negligible in a mix, anyway. which is why the kemper works so well after all.

    now with the two Diezels i have at home (VH4 and Herbert), the kemper simply fails to nail the trademark diezel midrange compression. the overall frequency spectrum is captured accurately, it's just more of a 'feel' thing. i know people will shout 'clips!', but this simply doesn't not reflect how an amp react to your playing (compression, sag, etc).

    bottom line is that seeing that i believe the kemper was developed using a recto/SLO type amp for matching higain distortion. in my opinion the unit works as well as advertised with these amps, but unfortunately fails with some other specific amps. knowing a fair bit about amp building, i can imagine that both scenarios (SLO and Diezel) can't be matched with the same algorithm. the SLO has four stages of cascading gain with a cold-clipper, whereas the diezel uses three stages driven VERY hard.

    i'm going out on a limb here, but i'm assuming that the profiling algorithm is not accounting for the behaviour of the individual gain stages in the amp, but rather the net sum. this would also explaing why profiling an amp with a boost in fronst doesn't work so well...

    i wonder if other users have similar experiences to mine.

    :2cents:

    Cool post -- thanks for the details. I do think nailing high gain with the KPA is tricky, and I posted some clips from a Cornford Hellcat profiling session in another thread. I don't know if the algorithm can really suss out how many gain stages are involved, and what's happening between them, or if it's just measuring the overall amount of clipping and dialing that in over the top. It *is* amazing that it gets as far as it does, considering the variety of preamp designs that exist, and the various methods they use to keep things like bass response under control as the gain is dialed up through successive stages.

    The VH4 profiles that came stock in my unit, by "RU Sirius", were actually modeled by Christoph -- or so they say in the credits. Unclear if they used SLO type circuits during modeling, or if those circuits simply model better for whatever chance reason. I am however sure that if these guys really sat around with a bunch of high gain amps and went super micro picky on it, they'd nail it. But you do have to be a bit of high gain aficionado to want to do that.

    If you've got any A/B Diezel clips I'd love to hear them -- I've played VH4s and will try to get my hands on one to model if I can.

    thanks for the replies.

    i'll make some clips of the VH4 vs profile to demonstrate the compressed 'signature' diezel response i'm referring to.

    the resulting profiles sound great indeed. but quite remote to the real counterpart. i would never guess it's a VH4 by playing the profile alone. still a lot closer than the axefx2 VH4 model i recently played (FW 9) :D

    Quote from hm2

    The VH4 profiles that came stock in my unit, by "RU Sirius", were actually modeled by Christoph -- or so they say in the credits. Unclear if they used SLO type circuits during modeling, or if those circuits simply model better for whatever chance reason. I am however sure that if these guys really sat around with a bunch of high gain amps and went super micro picky on it, they'd nail it. But you do have to be a bit of high gain aficionado to want to do that.

    If you've got any A/B Diezel clips I'd love to hear them -- I've played VH4s and will try to get my hands on one to model if I can.

    just for clarification, because I´m mentioned here:
    my VH-4 profiles were done by me alone, I had some issues to get the tagging right back then, so Christoph got some credits accidently ;)
    I did nothing fancy for profiling, just VH-4, Diezel 4x12" cab, Heil PR-40 mix.

    To add some to the discussion:
    I play a Diezel Herbert amp for 6 years now and know it very well. All the profiles of that amp, including my own, are not close enough to what I believe is the REAL Herbert sound. And yes, the problem is in the lower mids, where the Herbert has it´s unique strength, which sets it apart from every other amp I know.
    I plan to do some more profiles to steal Herbert´s secrets at last :)

    On the other hand, I have to say that the results of my Herbert profiles are more than useable. I do not hear the real thing, when playing them, but I get a tone, that is ready for recording and fun to play.


    PS:
    my profiles came stock with your Kemper??? are you sure?

    After having several ISO cabs over the years, I'd say that is the start of the problem with profiling. You get too much of a boxy sound. I have had zero success with doing that accurately.

    Try the R.U. Sirius VH-4 Profile. It's bang on with the VH-4 I have.

    Quote from r_u_sirius

    PS:
    my profiles came stock with your Kemper??? are you sure?

    Ok, that's funny!

    I just saw "Christoph" the other day and figured they must have been stock. But it's quite possible I installed them on the first couple days when I had no idea what I was doing. :)

    In any case they sound good! I don't have a VH4 in front of me, but since it's a high-gain amp I've played, I'm interested in heading back to a studio that has one, to run a few profiles -- just to see if it's an amp that happens to profile easier than mine, which I've had some trouble with.

    Did you run through preamps, or just the Heil directly into the Kemper? What was your gain setting for the Ch3 profile? I have some test clips I did at about 12 o'clock the last time I played one, and that felt about right for high-gain rhythms.

    Quote from hm2

    Did you run through preamps, or just the Heil directly into the Kemper? What was your gain setting for the Ch3 profile? I have some test clips I did at about 12 o'clock the last time I played one, and that felt about right for high-gain rhythms.

    as far as I remember, I used a Chandler Germanium preamp, that does slighlty add some colour.
    The gain setting for CH3 must have been 12 o´clock or lower.

    Quote from r_u_sirius

    On the other hand, I have to say that the results of my Herbert profiles are more than useable. I do not hear the real thing, when playing them, but I get a tone, that is ready for recording and fun to play.

    Give yourself a bit more credit, my friend. I had a Herbert for 3 years. It isn't all that bad what you have done. It is a tough one to capture, no doubt. I tended to scoop out the some of the lower-mids on your profile but it sounds great!

    Keep up the good work!

    :)