Kemper 600 watt Class D Powerhead vs. Real Tube amplifier

    Hello ALL -
    Having owned a Powerhead now for about 5 months, I thought to give an honest personal opinion of the Kempers' built in 600 watt amplifier section.


    Having A/B the Kemper with numerous Tube amplifiers I find that using the Powerhead falls way short in comparison to a TUBE amplifiers power output
    For my tests, the very same cabinet was used in all trials; a 212 Orange PPC212 with two Celestion 8 ohm Redbacks wired in series for a 16 ohm impedence.
    16 ohm impedance gives the Kemper internal amplifier a 300 watt output rating.


    A FEW Personal examples: 1. Marshall JTM45 Offset rated at 45 watts output blows away the Kemper powerhead in volume and sheer power.
    2. Vox AC30 rated at 30 watts output blows away the Kemper powerhead in volume and sheer power.
    3. MP CS-40 rating up to 75 watts output depending on the output tubes used. I tried with KT66's. Result: blows away the Kemper
    powerhead in volume and sheer power.


    CONCLUSION: Tube amplifier technology literally obliviates any amplifier output section based on Solid State technology - like the Class D amplifier in the Kemper.


    Kempers' 300 watts at 16 ohms - well, you go ahead and try it for yourself.
    The "measley" 30 watts of an AC30 tube amplifier will BLOW AWAY the Kempers 300 watt amplifier rated at 10 times more power!




    Don't get me completely wrong here, I still really like and use my Kemper Powerhead for a lot of obvious other reasons. :thumbup:

    600 Watts Solid state is equal to 120 Watts Tube power
    so "300 watts at 16 ohm" is about a 60 Watt Tube Power


    Most Tube Amps at around 10-12 o clock Master volume will be allready at full power (100 watts..120 watt or whatever...)
    everything further is just Powertube saturation. So to get at the Volume power you get from your tube amp at 10 o clock you will need to crank your 600 watt Solid state to almost 100%


    That being said-- i use the Camplifier 180...so its "only 180 watts at 8 ohm" and its still loud as f...*
    and really loud enough for a Metalband in a rehearsal room or on a Stage


    so @pacocito YES

    Ohm's law doesn't discriminate-watts are watts are watts. For a truly honest and objective comparison, you would need to measure the input voltage driving the various amplifiers as well as the output voltage and current when driven with the same input signal. You would also need to measure the harmonic distortion of each device.


    The results would surprise most people, especially those who endorse the "tube watts are louder than SS watts" thing.

    The only SS/ClassD amps I've played that compare favorably (SPL-wise) to, say, a 50W tube head is the Quilter Tone Block series. Those can compete easily. But nothing else in that price range comes close.


    So I don't doubt the validity of the OPs experience in the least bit.


    I'm quite certain the Matrix GT800FX and GT1000FX would also compare well, but they start at roughly double the price of the Quilter.

    Before i got my frfr box, i once compared my gt1000fx with a mesa 50/50 into a mesa 2x12.
    One thing i felt was the imidiate release of power from the tube amp compared to the solid state Matrix.
    You got that powerful boom sound from the speakers when you hit the strings, with the matrix you didn`t get that.


    I am not any electrical guru, but could it be that tube amps deliever power more rapidly than solid state? Or atleast in larger initial current?

    I had a Camplifier 180 with my toaster. Went over to a buddies and played his SLO100 through a greenback cab on "2" maybe "3" then played the toaster cranked at "10" and it didn't even come close to the SLO100 in volume :cursing:


    Sold it!


    Regretted not having a Kemper so bought an un-powered rack with a couple DXR10's and couldn't be happier!

    Beyond just volume, SS and Class D power amps lack the body and warmth of a tube head. I’ve heard a few times that the Fryette Power Station with the KPA & other modelers does a lot to add back what’s missing, though that is a tube power amp.


    Speaking to a number of SS power amp and FRFR cab manufacturers, none of them like the KPA power amp. Still, knowing that I still got the powered KPA because I can always use powered speakers or a different power amp with it if I want, though I’m a sucker for convenience.


    But yeah, anyone who thinks the KPA power amp is comparable to a tube head needs to share what they’re smoking.

    Edited 2 times, last by MementoMori ().

    Like 2

    Yes, no matter how I try, no matter what I do, there is no replacement for a Real tube power section…
    It’s not just about volume, in fact volume is the least of my worries, it’s about warmth, tightness in the bottom end, smoothness…The way a tube power section breaths.

    Quote from MementoMori

    Beyond just volume, SS and Class D power amps lack the body and warmth of a tube head. I’ve heard a few times that the Fryette Power Station with the KPA & other modelers does a lot to add back what’s missing, though that is a tube power amp.


    Speaking to a number of SS power amp and FRFR cab manufacturers, none of them like the KPA power amp. Still, knowing that I still got the powered KPA because I can always use powered speakers or a different power amp with it if I want, though I’m a sucker for convenience.


    But yeah, anyone who thinks the KPA power amp is comparable to a tube head needs to share what they’re smoking.


    There's no need to be passive aggressive when posting about what others think about gear.
    I think you exaggerate way too much when saying that the kemper SS amp (a 600w Bang & Olufsen model) is not even
    comparable to a tube amp, and insinuate that those who think it is are wrong.
    There are hundreds, if not thousands of bands and artists using the kemper+ ss poweramp, replacing a tube amp without any problems. There are plenty of posts to be found over the years by users replacing a tube amp with a powered kemper or other SS amps. I don't think it's a good way of gathering facts or information when you refer to what other amp brand makers (salesmen with a business interest) think of a competing product.
    It's easy to get stuck in a confirmation bias trap, not seeing what others think.


    I've seen many being fooled in blindtests when asked if they think it's a tube amp they hear/play or a solid state (when playing a kemper with SS amp). That includes the kemper SS, Matrix SS, Camplifier SS and some other SS amps.


    Some info previously posted about solid state vs tube amps.
    copy paste from a previous post:
    "Here is a link with some food for thought info, Amp Power Myths, tube vs solid state:
    http://ww1.guitarnuts.com/amps/myths.php/?gtnjs=1
    As mentioned earlier, a 100w is 100w both from tube or ss amp when measured, RMS. compared with exact same setup.
    Yes a tube amp can be pushed above the rating, but that can only add a very small extra dB gain.
    If you double the watt in an amp you only get about 3dB louder.
    So a 200w amp is only 3 dB louder than a 100w amp. A 100w tube amp don't add that much dB over the rating.
    If you want double the percieved volume then we need about 10xW, meaning going from a 100w to a 1000w.
    It's much easier to get louder by using a very loud sensitive speaker.
    sensitivity, also known as SPL (Sound Pressure Level)
    A 40 w amp with a very loud 100dB sensitive speaker will sound louder than a 100w amp with say a 92dB sensitive speaker.
    A 512 w amp coupled with an 86 dB speaker will be just as loud an an 8 watt amplifier with a 104 dB speaker.
    Here is a chart good for interpreting SPL ratings."
    http://www.colomar.com/Shavano/spl.html


    As a side note question, MementoMori, are you affiliated with any company?
    I thought your signature used to say something like "social media expert, HOSA company" or similar.
    I've seen you recommend HOSA cables recently in the forum. Just wondering why it was removed from your signature since the forum rules require forum users to list any affiliations. Apologies if I'm mistaken.

    I've never been in a musical situation where the KPA driving a 2x12 V30 cab is too quiet. I like my hearing too.


    Comparing the KPA to a tube amp is like comparing a top fuel dragster with a Tesla. The dragster does ONE thing. Nothing else. You need at least one other vehicle just to get it to the track. You need hearing protection to be near it. But nothing sounds and feels like a dragster.


    The Tesla does a good job of that thing as well, but it also has a HUGE list of other incredible features.

    Quote from HappyKemper

    As a side note question, MementoMori, are you affiliated with any company?
    I thought your signature used to say something like "social media expert, HOSA company" or similar.
    I've seen you recommend HOSA cables recently in the forum. Just wondering why it was removed from your signature since the forum rules require forum users to list any affiliations. Apologies if I'm mistaken.

    It’s not required to list your employer in your signature here, and no idea why it would be. I once answered a single question asking which type of cable that was needed for a specific function and linked to a description of It on our website before, though the Hosa website doesn’t allow you to buy online, so it was more of an FYI. I removed the signature after getting some awkward messages here as it relates to my job. I’m here representing myself not my company. At no time did I attempt to advertise or sell Hosa products here unless I was asked in private.


    As for the power amp discussion, I’m not saying people can’t use SS power amps without success. Hell, I have for a long time. Still, being in the same room with both there’s simply no comparison to my ears. The main reason my KPA can hang with my other guitarists Orange is the passive Mission cab I use.

    Just because someone makes their own product doesn’t mean their opinion is meaningless. Especially when these guys know their stuff and speak openly about things, mainly because I work in this industry and people speak their true feelings privately more easily. They also compliment competing products and all these guys know each other (and are often friends), so it’s not as if their motive with me is to lie. Since then I’ve compared Kemper power amp to some of their powered FRFR cabs to see what they’re talking about. I still use the powered KPA for convenience but I have a better understanding of the broader spectrum and what it offers. But in the end if it works for people then that’s perfectly fine. I just don’t like pretending all things are equal (and there have been many on this forum in different threads making such claims).

    Edited 2 times, last by MementoMori ().

    Like 1

    If your tone is complete (like the Kemper), then you want your power amp to faithfully deliver that, regardless of the frequency range (eg: bass guitar, violin, etc, like the KPA does) and not add any extra artifacts. I think the Kemper power amp does a great job.


    With your tube amp the power amp is designed to add extra goodness to the sound. It's true that there's something extra about a great real amp, but there are too many benefits over and above a tube amp to worry about that. Overall I like my sound better with the KPA than with my amps in most situations.

    Yes, the KPA power amp is meant to be more transparent. You’re going to lose the unique characteristics of a tube power section by doing so. I understand why, just explaining why they aren’t the same and the KPA leaves me wanting after playing alongside a proper tube amp (even ones I don’t particularly like even).

    There's almost no difference to me when it's set up properly and pushing a great guitar cab. No chance I'm going to get drowned out by someone. It'd also be their last day in the band if they jumped out of a rehearsed mix with a screaming tube amp that loud.

    Quote from MementoMori

    Yes, the KPA power amp is meant to be more transparent. You’re going to lose the unique characteristics of a tube power section by doing so. I understand why, just explaining why they aren’t the same and the KPA leaves me wanting after playing alongside a proper tube amp (even ones I don’t particularly like even).


    I made some direct profiles of my Mark V a few years ago, then ran both it and my power rack into identical Mesa cabinets. The A/B comparison was close enough that I wouldn't have been able to tell which was which if I were blindfolded and somebody else was randomly switching the A/B box.

    Quote from Frodebro

    Ohm's law doesn't discriminate-watts are watts are watts. For a truly honest and objective comparison, you would need to measure the input voltage driving the various amplifiers as well as the output voltage and current when driven with the same input signal. You would also need to measure the harmonic distortion of each device.
    The results would surprise most people, especially those who endorse the "tube watts are louder than SS watts" thing.

    Most of us don't have the opportunity to go around with measuring tools to test out every amp in the world so we have to rely on advertised specs. A tube amp advertised as 100w is going to be louder than a SS amp advertised as 100w. You can argue "watts is watts" all you want, but all that matters is what's going to blow up my speakers and what is safe? Even cabinet manufacturers specify a difference between tube watts and SS wats when rating their cabinets.

    I will bet anyone, any amount of money that I can pick out my own amplifier versus the kemper (thru a 4x12 cab) every single time in a blind test… The kemper is about 80%, which is surprisingly, extremely good!
    For live use with in ear monitors, it can’t be beat but there is something that’s not there through a 4×12 cabinet… And I’ve spent hundreds and hundreds and hundreds of hours over the last five months wanting, trying, doing everything possible to match it…