KPA rack and VHT poweramp problem

  • Hi everyone,


    I just bought a KPA rack and I have been very pleased with it through a VHT 2/50/2 poweramp at quite reasonable volume levels at home. However when I took my KPA at my band's rehearsal place and cranked up the volume of my VHT it sounded really shitty. And by this I mean the bass frequencies were over-emphasized. I tried to compensate this by turning the bass knob of KPA to zero and also the depth knob from VHT but still there were too much bass. I tried with many hi-gain profiles and tried to adjust pretty much everything but there was always this "ooomph" sound that choked the tone. I play in a drop B tuning but that has never been a problem. Also, I have played many "real" amps with the same 4x12 cabinet and I have never had this kind of problem. Obviously my VHT is working properly because I tested it with another preamp and it worked fine.


    I loaded the graphic EQ settings on my kemper and dropped all the frequencies at 80Hz by -12db and that seemed to be the only tolerable solution. But I was not happy with that either.


    What should I do? Sell my VHT and 4x12 cabinet and buy a active PA?? Or return my KPA to thomann and buy a "real" preamp instead (as I have never had this kind of problem with those). Or should I buy 30-band graphig EQ between KPA and VHT?


    Please, give me some advices? I'm frustrated... :pinch:

  • The first thing to do would be to adjust the EQ on the monitor out in the master section. If this should not precise enough i would try locking the studio eq in the x slot. Set a maximum cut starting at the lowest possible frequency. Then slowly raise the frequency up the point where the low end still sounds punchy but not overemphasized anymore. Think of it as a high pass filter.

  • Hello,


    same problem here. I switched from AXE FX to the KPA in Spring last year. While the AXe sounds great with my VHT 2502, the Kemper sounds from the beginning bassy and boomy. No way to use this in a live situation. So I decided to wait until the internal Kemper power Amp is available, and then will make some tests with this unit again.
    I'm a little old scholl plaxer and need the punch of some 12" speakers on stage, I never felt comfortable playing over the PA System with inear or our qsc hpr12 wedges (neither with AXE or Kemper).
    At the Moment I'm playing a normal Guitar-Effect-Amp setup and use the Kemper only for recording situations.
    sorry that I have no better answer
    Jens

  • The KPA can for sure deliver lots of bass.
    According to the OP Fletcher - Munson comes to mind. http://en.wikipedia.org/wiki/Fletcher%E2%80%93Munson_curves


    Never tweak at bedroom levels, tweak at rehearsal levels instead, turn down that bass and emphasize the mids.
    that's the basic recipe for good tone within a band setting.


  • Never tweak at bedroom levels, tweak at rehearsal levels instead, turn down that bass and emphasize the mids.
    that's the basic recipe for good tone within a band setting.


    definitely!
    when touring or when inside a pro situation willing to set up your sound, I was tought to not even do it in your home unless it is a suitable place for it. Thus:
    1) go to a place which is open, i.e. something like a club or a concert hall. sometimes they have cleaning days in which they don't raise any problems in letting you use the amp for a couple of hours. a rehearsing room would do it as well
    2) cut out all the FX, but use only KPA (as a pre) power amp and cabinets. place your cabinets/speaker at the same height as your ears. this way you will most likely hear what the mic will hear in the concert. Crank the volume well up so that the power amp's tube are excited at least a bit. there is no point of using a tube power amp if you don't take advantage of the tube features!
    3) when the sound is ok, add the FX and tweak them as you wish.


    this is, basically, the easiest way to do...........don't be discouraged by what you hear when playing and testing. Get to know the limits and the benefit of your rig. I remember I did this set up with the mesa 290 together with the triaxis, a really difficult machine to handle. the first hours it sounded like carbage. but after I got to know it I was able to blow things up!


    hope this helps

    "...why being satisfied with an amp, as great as it can be, while you can have them all?" michael mellner


    "Rock in Ecclesia" - new album on iTunes or Google music

  • To the OP:
    Of course a higher sound level emphatizes the lows and the highs.
    To exclude the too many variables, you should test your patches\gear at different volumes in the same room and in the same positions.
    The FR of a digital device is much broader than classic guitar amps\cabs, and in some rooms you might discover resonances which were not perceivable before. The placement of the cab itself in the room can change the sound a lot. Sometimes it's enough to raise it from the floor, to take it far from walls and/or corners, or to not put it on a wooden, cave, resonating floor\piece of furniture\stage.
    HTH :)

  • May i ask, if you have disable the cab sim ?

  • This only happens at high volumes, meaning there's something that changes when you crank your PA.
    My guess would be the tubes, not surprisingly.


    The KPA does a very, very good job of emulating cranked tubes - coupling that with extra compression from actual tubes, or that plus actual compression from guitar speakers being pushed hard by cranked tubes, makes for a boomy, painfully punchy sound in my experience.
    You might get a little extra leeway if you don't boost the 80Hz, perhaps even cut it a bit, drop 'tube shape' and 'sag' to 0 and use the main out, not the monitor out - but even that didn't really get me to anything really good.


    I switched to an active wedge - solid state, flat, with a horn and woofer - and me and my bandmates are happy. Happy enough that i'm selling my amp and cabs.
    I wish i could give better advice, but i think the Kemper is just not meant to be used through generic guitar gear unless maybe if you dial everything in at high volumes, but that's just not practical.

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