Kemper 600 watt Class D Powerhead vs. Real Tube amplifier

The inboard poweramp is one of the reasons I got a Powerhead. Up to now, I didn't have to use it at a higher volume than -8 dB on my Palmer cabinet (2x12 @ 8 ohms with V30, closed back). But here in Mauritius we never play at deafening volumes either

here's a gig I did with it (the camcorder which recorded the sound is the one most far from the PA) :

The other guitar player in my band used a Diezel Herbert, and I hear myself better. But the camcorder was on my side of the stage too…

Why always this comparison? If you want tubesound, please, buy a tube amp. If you want 4x12-sound, please, feel free to buy a
4x12. And so on. But it's a fact the KPA is very popular amongst recording studios, professional studio- and live musicians, highly recommended. The KPA isn't a tube amp. Yes, the sound will come close but never 100%. Why? It isn't a tube amp. Same with FRFR speakers, they will never sound 100% like a dedicated guitarcab. Again, very close but never 100%.
In the end, no one can tell, listening to Spotify or any other medium, whether it is recorded with a real tube amp or KPA (or Fractal or Line6 or Amplifire or Amplitube or Bias or........).
Personally, I don't give a f*ck, as long as it sounds good to my ears. And I think the majority thinks the same.

Hey DML, I agree 100%, a good guitar tone is a good guitar tone!
However, why the comparison? Simply because of the way this unit has been promoted, it is not an amp simulator, it is an amp ‘profiler’… with all the blind tests where people couldn’t tell the difference… at least you are in touch with reality, in that there IS a difference… Thank you!
Every single video promoting the Kemper has done an A/B comparison, Insinuating the consumer would not feel or hear any difference!! I believe this is why guitarists are harder and more picky with the Kemper than all of It’s competitors…
I totally understand that some people are very happy with how close it gets, but we are all different, and playing through a 4×12 cabinet, it’s not getting close enough for me ... I soooo wish it was! You have no idea…
Now, there is a trade-off, the simplicity of setting up Kemper at a gig is phenomenal! No cabinets, no speaker cable, no FX units, no cables, I can literally set up for a gig easily in less than 5 minutes, without breaking a sweat and or a sore back…
And, in the end, you are absolutely right… No one is going to know the difference in the audience, whether you’re using a POD, Line 6, Axe FX, a helix, a bias... they’ll just remember that you played Sweet home Alabama, or Stairway to Heaven…

Quote from PhilsKF

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.

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PhilsKF, I and others have compared the kemper SS and tube power amps played through the same speakers and have no problems matching the volume loudness ranging from 1x12, 2x12, 4x12.
SS and tube power amps will have about the same RMS at the same watt with identical setup. See my previous post. A doubling of the power amp watts only results in about 3dB more volume, and 10x watts will result in about double percieved volume (9-10 dB).

When you describe huge volume differences in your examples it sounds like something is wrong to me.
Have you made sure you have turned up the power amp levels in the kemper settings? Perhaps you have a defective unit.
I have seen a few forum threads where users asked about low volume in the kemper power amp, and other users pointed out how to set and turn up the correct volume settings in the kempers menu settings and that solved the volume problem.

There will be sonic differences since the kemper profile used has captured the power amp color and dynamics from the tube amp it profiled. Therefore a transparent power amp makes sense in the kemper. Playing it through a tube power amp will color the sound more away from the original tone that was profiled. Both can sound great though, nothing is right or wrong, but one option is more true to the original tone and one is more colored. Some tube power amps are very stiff, some in the middle and some very spongy.

For me… Personally, it has nothing to do with volume… I don’t play death metal, my normal guitar volume hovers around 95 - 100 DB through a 4×12 cabinet (measured sound pressure level off axis 10 feet distance from cab)

Quote from MementoMori

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).

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

I have no problem with you prefering tube amps, but I don't get why you initially post your personal preference as some elite univeral truth and then ridicule and insinuate all those who have no problems replacing their tube amps with ss amps are wrong.
It's passive aggressive, completely unneccesary and only brings negativity to threads. It's not the first time I see such posts often derailing threads.

"It’s not required to list your employer in your signature here, and no idea why it would be"

Most gear forums have clear rules of conduct like; not spamming, no swearing, polite manners, no personal attacking other forum members, no marketing, disclosure of affiliations etc. I was sure I had seen them on the Kemper forum but I guess not (kemper, post a rules of conduct please) , still I'm sure they want gear affiliations to be seen in the signature.
Net transparancy is more important now than ever in social media to protect us consumers. A steady rise in bought reviews, bought product placements, agenda trolls, planted forum/facebook opinion users etc.
An example: Rules of Conduct on The Gear Page Forum https://www.thegearpage.net/board/index.php?help/terms

"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)."

From a consumer perspective it's basic life psychology 101 not to trust company business sales people reviewing competing products. The web is filled with that and it's not pretty. Companies with good business ethics don't do it.
Many have been fooled by digital amps and SS poweramps, including myself. They can't be 100% molecular perfect but they don't need to be 100% to fool many people, it's easy to accept that fact. Talking absolutes makes no logical sense and is never constructive.

I just got my Kemper rig last Thursday and loading the Choptones Friedman JJ 'Fried Jerry' profiles I was blown away at how accurate they are to my real Freidamn JJ head and 4x12.
The clarity mixed with crushing power and all the sweetness of a Marshall with out any of the harshness was evident from the first chords I hit. The solos are pure bliss through the Kemper. Very similar to my real head and in some ways smoother! Roll the vol off and wow so much more real amp like than I could ever get with my Ax8.
I am using a Freidman asm in the house and a Xitone/CLR combo in my studio.
The JJ is on Reverb.com right now if that tells you how happy I am with my Kemper!

Hi Phil, it’s all good… Sometimes we can pull a little nugget from one of these threads that helps us get one step closer to our holy grail of tone!
Keith

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Is it a painting or a picture of a painting? Look at the bigger picture. I see a lot of people discussing how they try to get it to sound the same. Boring af. Make new sounds

Missing this discussion is that a 50W tube amp cannot put out any more volume CLEANLY than a 50W solid state amp will. Ya know... because, well... physics.

But a tube amp going into break up can sound very pleasant (even while still being perceived as "clean") well past the 50W barrier. Indeed, at full bore a 50W tube amp can easily put out 150W or 200W.

OTOH, a solid state amp is going to put out 50W, that's it, period, and no more. Once you cross that 50W threshold the distortion is brutal. So my 1000W EV ZLX-12P's might put out 1000W, but only measured at a certain frequency, and are probably breaking up WELL before that with program content. I'd be surprised of they can put out 300W cleanly, and even less still if you want them listenable. Then add to that the logarithmic nature of audio dB output and it starts to make sense why my 50W tube head is just as loud as the ZLX-12P's.

I mentioned the Quilter Tone Block series earlier... Pat Quilter has stated that the Tone Block 200W series of amps are actually 400W amps internally, with the 2nd 200W on board for headroom and transient spikes. The TB200 I owned compared easily (EAS-I-LY) to my 50W head.

Seems to be a couple of challenges here...

Is the KPA loud enough? It is for me and I have played at deafening volumes in the past so the built in amp is good enough. I have never run out of volume. I ignore the 100 watts vs 600 watts question because its never an issue. I would struggle to believe anyone does not get enough volume from it.

As a SS amp is the KPA one any good - to me its transparent and loud enough so I see no reason to look to others such as Matrix.

Is SS as good as tube amp - they are different. You expect colouration with a tube power amp as part of the sound. You do not want that with a SS amp.

Does the KPA sound as good as a tube amp? Straight into a 4 x12, perhaps not quite as good although I've not been using merged profiles. It does lose something in the removal of the cab in the signal chain. FOH - totally..FRFR backline yes does have the same "thump" but I don't really expect it to. I'm running a 1x2 so how could that sound totally like a 4x12...not the same config.

I now only run a cab for looks and a bit of backline and I'm less concerned about my backline sound as long as it doesn't distract my playing, knowing my FOH sounds great.

I thought my sound was good with my ENGL but never had so many compliments on my sound with my KPA.

One thing that may have been overlooked here is that the OP is using a 16 ohms cab, meaning that the poweramp will output 300 watts instead of 600 ?

Quote from Frodebro

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.

Same. I've made direct profiles (dummy load line out) of my Tone King Skyking combo, and when playing the profile though the powerrack into the Sky Kings speaker, imo, it sounds great. Very hard to distinguish the two in both tones and feel.

Admittedly, I have made some direct profiles that didnt turn out so great (poor tone and feel compared to the real amp) but I just deleted those ones. For the majority of them its pretty spooky how close it is. Only did this is a nerdy curiosity experiment as I use the main outs direct to FOH almost 100% of the time.

Power on tap (volume) seems more than adequate also.

Different strokes i guess.

From : link

General Electric showed in a study in the 1960s that the human ear used higher ordered (and in particular, odd ordered) harmonics in order to sense sound pressure. This is actually quite easy to demonstrate with what is today rather simple test equipment, and according to the Radiotron Designer's Handbook published by RCA, we have apparently known since the 1930s that we are more sensitive to higher ordered distortion products (this might be the 'Inconvenient Truth' of audio, as this particular fact is largely ignored by the majority of the audio industry).
The ear has a masking principle wherein louder sounds (distortion) mask the presence of quieter sounds (detail) and also because the ear/brain system converts all forms of distortion into tonality (in this case, brighter and/or harsher). The odd bit is that the ear/brain system also has a tipping point where tonality caused by distortion can be favored over actual frequency response errors. So you can turn down the treble in a bright system, but if the brightness is the result of distortion rather than frequency response, it will still sound bright!

So this is why a low distortion studio monitor will not necessarily sound loud, but will sound very detailed.
And a tube amp which generates more odd harmonics than the Kemper profile you're comparing it to may be perceived as having more sound pressure, even when a voltmeter or scope would show the same reading as the Kemper output.

Quote from Finally

Can someone quantify the "body and warmth" parameters that tube power amps supposedly possess?

If you crank one, it does produce quite a lot of heat, plus the smell. Can also cause ear bleeding.