KEMPER PROFILER Main Manual 5.5
A PROFILE of a guitar amp, tapped at its effect-loop send jack, representing the preamp section of this amp. This
Direct Preamp PROFILE can then be played back into the effect-loop return of the guitar amp, and further through its power amp section and a guitar cabinet. The following graphic illustrates this configuration for information only - we don’t recommend this setup.
It is unclear why the manual doesn't recommend creating preamp profiles. I suspect that Kemper believes that the results are usually sub-optimal.
There is no supported way to profile a power amp by itself. The signal must first come through a preamp. However, it would be possible with a split stack. You can already use cabs from other profiles which are part of the stack. Why not have the same ability for the preamp and power amp sections? If split stacks were possible, you could create a DAP, then split its pre and power amp sections for use as individual components in a stack the way that cabs are selected.
Here are some examples of split stack uses and benefits.
You could make DAP profiles of an amp covering all of its multiple wattage and configurations. Take the Mesa Boogie 5:25 or 5:50 Express Plus amps for example. From the manual:
Each power mode has it’s own tone-spawning operating class and wiring configuration! Choose the full power mode of either amp (25W in 5:25+ or 50W in 5:50+ ) for Class AB running in a Push-Pull configuration for punch, authority and headroom. Or, kick down to 15 watts (25 watts on the 5:50+ ) for Class A Pentode for a more silky, vintage voice with enhanced clip potential. And for the ultimate in low wattage power expression knock it down to the 5 watt mode... now you’re running one tube in Class A Pentode wired in a Single-Ended configuration.
These are in effect three totally different power amps. The idea is to get profiles of all of the circuit configurations of the power amps. I'd make three or four profiles with varying gain levels from the preamp to cover gain level input of each power amp circuit. Note that the preamp's only contribution to the power amp's profile would be gain output at the power amp input. Once you have made these DAPs, you could use a totally different preamp profile assuming split stacks were available.
Now you could place a Vox AC30/6 Top Boost preamp profile in front of a Class A 5 watt Single Ended Mesa with a single EL84 tube. Or try a Fender 5F4 Super preamp profile with the 15 watt 2 X EL84 tube Class A Mesa power section profile.
Sure, you could profile these amps with their own preamps, but the ability to mix and match and preamp profile with any power amp profile would greatly increase available tone pallets. Also, these classic amps had no effects loops. That means they can't mix and match pre and power amp sections without hardware modification. That would greatly drop their value.
Not so with Split Stacks. With Split Stacks, any vintage amp without a hardware loop can have one. No mods needed.
I like to use multiple Preamp profiles with a hardware amp and cab. I can do that now by loading a preamp profile on my Kemper, sending the signal to my Mesa 20/20 power amp. The 20/20 uses two EL 84 tubes.
But what if I had a Synergy Syn 2 hardware system and I want to match the Marshall Plexi module with EL34 tubes, like the actual Plexi amp? The effects loop on my Marshall JCM-2000 DSL 401 combo is parallel, and feeds the dry preamp into the effects return. So I can't feed the power amp section with the Syn 2. With Split Stacks, I could profile the DSL and just use the power amp section.
The Kemper currently has 4 mono stomp slots, the stack, and then four stereo effect slots. With Split Stacks, you could potentially place effects between the preamp and power amp sections instead of after the stack. That would be a more traditional placement for effects.
You could also potentially run a hardware multi effects unit between the pre and power amp sections if the X slot could be placed there . This scenario would require that that the hardware effects be mono. However, potentially Kemper could make the redesign allow for a stereo return from the X slot into the power amp section of a split stack. There might be enough DSP to handle a dual mono (parallel) amp section. Or possibly, since effects DSP load could be lightened by using an external hardware multi effects unit, limiting the use of on board effects could make enough DSP could be made available to make this possible.
At present, I use my Kemper with my UA Apollo 8 interface to combine UA effects plugins with my Kemper. I use the X slot, placing the Apollo 8 there, connecting the two units via the analog send and the stereo returns on the Kemper. Having the fantastic sound quality and near zero latency of the UA effects is awesome.
However, I haven't been able to figure out a way to connect via S/PDIF, placing the Apollo 8 into the X slot. (Anyone who can show me how to do that, please speak up.) I will say it now. There should be a way to use the S/PDIF ports as a routing option for the X slot hardware connection, even without Split Stacks.
I have also used the Apollo 8 as a power amp section for a preamp profile. Some of the UA amp sims (Fuchs, Freidman, Suhr ) let you bypass the preamp or the power amp sections. So, I have profiled my Mesa Recto Recording Preamp , my AB763 clone (Fender Blackface), and the Preamp from my Marshall JCM 800 DSL, and I use the power amp sections of the Fuchs Train II, and Friedman BE-100 and DS-40 UA plugins.
So what does this have to do with Split Stacks?
With Split Stacks on the Kemper, I could use the UA effects and guitar pedal and amp sims in a totally flexible manner. The split Stack architecture would allow combination of any preamp, power amp, cab, or effect from either device to create a custom rig.
Of course this would also work as well with Line 6 Helix, Fractal FX, Mooer, Boss, etc., hardware units.