Using ONLY the power amp of the Kemper PowerRack

I believe you could just turn off the stack section(amp,eq,cab) as well as effects and get totally dry signal being projected to use it in the manner you are referring to.

I am by no means an expert at recording and the methods you are referring to but I do know that signal passes through with those sections turned off. Hope that helps.

Hey Chris, welcome here

Slightly OT, I think it has to be underlined that the sound of a poweramp "alone" doesn't exist. It has to interface with a load, which will give it an important part of its sonic signature. Using a DI will not give you the "neutral" sound of a poweramp, but rather the sound of that amp with that load.
The interaction between an amp and a load (a cone for example) is complex and varies with the frequency, so it can't be reduced to a single number because a cone is electrically complex (the load is never purely inductive).
So, by attempting at this, you'd have the same "error" (from a quantitative POW that the KPA makes when telling "the cab" from "the amp".

HTH

Oh, I thought you were talking about a dummy load.
In the case you specified, the amp will see the cab and the DI as a whole, so the DI will give its contribution anyway.
Basically, what you do is to take a mic out and a DI in the equation. You may like the result better or not when you swap cabs from the KPA

I didn't understand well, what you're trying to do, but one thing I want to tell you about the Stack section, especially Amp & Cab part of it.
There's no perfect separation of AMP part and CAB part in a profile. The Profiler tries to split the profiled data into these two parts. You always profile the whole chain and the Profiler internally tries to guess what of the captured data should be part of the amp and part of the cab section. It does pretty well, but not 100% accurate.

You can achieve great sounding results by changing the CAB part of a profile (or switch the CAB off and use an IR via CabMaker). But don't expect 100% accurate, realistic reproduction compared to the real amp/cab combination.

Hope this helps to adjust your expectations.

This is the point I was trying to make: there's nothing like "the most realistic sound" of a poweramp, because an amp always has to play against a load, and any load changes the amp's character and sound, even a DI. It's a relationship, not a solipsism

Quote from AHChris

I want to leave cab, mic, preamp and A/D converters out of the equasion as far as possible, to create the most realistic profiles of my amps I

The point I tried to make is:
Even if you profile without cabs and mics, a profile on the Kemper will always consist of AMP and CAB information because it can't perfectly distinguish. After the profiling process of a DI signal of your amp, the CAB part of a profile will not be empty, so to say. So, if you make a profile without cab and mics ... and then switch off the CAB part, some of the amp's sound will be gone and can't be restored by just using some self-generated CAB IR.

Quote from viabcroce

This is the point I was trying to make: there's nothing like "the most realistic sound" of a poweramp, because an amp always has to play against a load, and any load changes the amp's character and sound, even a DI. It's a relationship, not a solipsism

This. A poweramp is not complete unless it feeds a load.
An amp with cab x sounds different than with cab y not only because the cabs sound different but the amp itself sounds different, too.

Hi AHChris,

I think you might be over-analysing the situation.

When you get your Profiler and start making your own profiles, I'd recommend doing the easy thing first, which is profiling the entire chain (amp, cab, mic) of your proven, working sounds.
That is how all the producers I know work with the profiler. Build up your library of (real world/production reday) tones, and use them.

"I thought it would be best to seperate as many components of the chain to get the best possible results."
I see no reason why this would produce superior results.

Besides, a profile is much more than a 'snapshot' as you put it, but you'll probably have to experience the Profiler first hand to fully appreciate what that really means

And there is something to add.
Many have stated here correctly, that a tube power amp can only be measured or profiled correctly by using an authentic load: a real cabinet.

But there is more to the famous story of the interactions between amp and cab, that has rarely been told. The tube power amp has a significant impedance itself. This is what interacts with the impedance of the cab.

If you measure a cab, the authenticity of the amp driving it is cruical, since the frequency responce is affected by that. A solid state amp will create different results.

Strange:
Cabinet impulse responces from commercial suppliers are en vogue these days. Those IRs are sometimes taken by using solid state amps, sometimes by tube amps. But how authentic are these IRs? Can they be combined with certain tube power amp simulations to form a realistic result? Can I swap cabinets on a modelling amp without bending the reality? Where do the interactions go?
I have read so much cork sniffing and pseudo expertise in forums about separating and recombining amp and cabs. But I have not seen a single person asking this question or pointing out this specific problem in years. Not even real experts like Jay Mitchell ever mention this topic. Am I wrong?

Quote

I have read so much cork sniffing and pseudo expertise in forums about separating and recombining amp and cabs. But I have not seen a single person asking this question or pointing out this specific problem in years. Not even real experts like Jay Mitchell ever mention this topic. Am I wrong?

No, you are certainly not wrong. But luckely there are some forums and people who have shared this knowledge on the net. And this is why some big Cats still play their modeling or profiling (pre)amps with Tube power amps and real cabinets. None "FRFR" will give you this. It is science, simple. But again it is up to everyone what to believe

My question is. Can the KPA do this interaction stuff including the change of impedance by frequency in a live set-up?

This is why the Koch ATR-4502 1U Rackmounted poweramp got my interest. Hope to test this baby soon The interaction between tube poweramps and speaker cabinets can only (for now) be created by real tube poweramps and real cabinets. So I prefer this above the other "Bonanza".

Quote from DADA

None "FRFR" will give you this. It is science, simple.

Unless you use a Profiler, which has already taken into account the power amp-cab interaction

To use the power amp of the Power Rack put the Mono Loop in the X slot and turn off Delay and Reverb. Send your signal into the loop return.

When you make a DI profile and tap the tube power amps speaker output, while the target cabinet is the load, you can then recreate the same interactions using the internal power amp and the same cabinet.

Quote from ckemper

When you make a DI profile and tap the tube power amps speaker output, while the target cabinet is the load, you can then recreate the same interactions using the internal power amp and the same cabinet.

AH HAAA. Does this mean that a profile captured this way HAS this interaction between the profiled poweramp and the speaker cabinet??
But still there is the factor of ANOTHER interaction between the LIVE used (tube) poweramp and guitar cabinet. Or the LIve used SS poweamp with "FRFR" speaker.
Will there then be TWO interactions?

Sorry to bother but I just like to understand this so essential part of the whole chain in a LIVE setup