Monkey_Man you’re too kind, I think I tend to stick to what’s safe and I know rather than having any range.
Well, from an outsider's perspective, you're a "veritable cornucopia" of moods, brother.
It may not seem so to you, but it's impressive from an onlooker (listener's) point of view I reckon.
Turns out I do have both the In and Out S/PDIF cables connected to my AI (18i8) here. I'm not using the DAW out/KPA in channel, just have the cables plugged in to both channels.
At the friends house (6i6), I was connected to KPA Out only.
I'm not using the re-amp feature at all, but yes, with both S/PDIF cables connected, Internal sync works fine for me, at the moment.
It's not about whether or not they're both connected, mate. I'm talking about not being able to monitor, without clicks and pops, the KPA's S/PDIF out whilst it's slaved (via S/PDIF) to your interface. That slaving will sync the KPA's S/PDIF input only. The only way to have both S/PDIF in and out synced properly is to set the KPA as master and your AI as slave.
As I said to Kempermaniac:
If it's the S/PDIF out from the KPA to the AI, the AI will have to be set as the slave (external clock) and the Kemper to master (internal clock). In this case, you'll be able to listen to both the KPA's S/PDIF in and out without issues.
I think you're very good at creating any damned vibe you aim for, Per. Kudos to you, brother.
The Vibe Guy™. 
Thank you, Ivan! 
What? Only 18 guitars in the pics? Surely you have more. C'mon mate, 'fess up.
Welcome, Stratman. 
I’d love to figure out a way to power my Kemper though, bias is ok although not the best sound and it just doesn’t feel very good to play, I wonder if a battery backup would last more than a couple of minutes with it.
I wonder if something along the lines of what campers use in their caravans might work, Per. I mean, they run fridges, TV's and all sorts of things...
On my side in and out are both connected all the time. But atm I only use Kemper Out to Interface In (for monitoring via my studio speakers).
You mean analogue out from the Kemper, Stephan?
If it's the S/PDIF out from the KPA to the AI, the AI will have to be set as the slave (external clock) and the Kemper to master (internal clock). In this case, you'll be able to listen to both the KPA's S/PDIF in and out without issues.
When the AI's clock is set to internal, there's no way IMHO that your S/PDIF out from the Kemper won't be clicking and popping, except on rare, "lucky" occasions, which is why I asked if you meant one of the analogue outs.
I don't use Performances, but this makes good sense to me.
+1
Only "catch" is I think Kemper would have to create an additional layer of level control between the Rig and Output tiers, so it could be tricky to implement / involve a fair bit of coding. 
JSB the point isn’t whether or not you are able to do it just now. If you say that you have it working without any clicks and pops I have no reason to doubt you. However, the technical spec (according to CK himself) is not capable of doing this robustly due to hardware limitations. With most things in life it is possible for unlikely and unexpected event to occur by chance on occasion. However, that doesn’t mean the can be recreated at will or be expected to last. You may be experiencing a fluke period where everything is working beyond its apparent limitations but I wouldn’t take that as evidence that it will continue to do so indefinitely. I would enjoy it while it lasts but don’t be disappointed when it eventually stops either.
Allow me to clear up the confusion, Alan:
Throughout this discussion, we've assumed JSB and Kempermaniac had both their S/PDIF inputs and outputs connected to their interfaces, probably because they didn't indicate otherwise in all those posts:
I am using Internal source for clock sync, tested both 6i6 and 18i8 now; with, 96KHz, 128 samples, works fine.
I can play my Kemper head through S/PDIF with internal clocking of the interface too.
I remember being told that Head and Rack would never be S/PDIF Slave, but I really only wanted not to have to change the Sync Clock source on my AI - which I'm no longer doing. I no longer have to set my AI at External or S/PDIF. But will it last?
Except I didn't have any clicks, at 96Khz, 128 samples. If you haven't tried it, give it a shot.
I updated to 7.1.2 release, and am still able to run Internal clock sync for S/PDIF, cleanly. I would've thought people would be happy about this.
Finally, in post #558, he clarifies by confirming that it's set up as described by digbob earlier.
This is what I'm experiencing, and am able to use Internal sync with S/PDIF.
JSB and Kempermaniac appear to only be using the S/PDIF inputs on their KPAs. If they'd connected their outputs at the same time and attempted to listen without setting their IF clocks to external (Kemper in this case), it'd be a different story.
You nailed the vibe again, brother.
Wuddun, mate. 
Man, I love this, Per!
The theremin-like monosynth, the mood change to the acoustic section... brilliant, man.
You should ask the power company to ensure more-frequent outages.
Congrats, Brother Ivan!
We almost lost you there for a while, but thank God you were able to be "coerced" into returning. 
Thank you yet again, Mick!
Welcome, Andrevv. 
You’ll have to excuse Darrell’s tolerance for bad tuning:
Same here, Mud, but they're not lasting as long as they did the other day, thank God.
Post #2, Greg:
Make sure the global noise gate isn't set too-high.
Well, stomp compression is a process (as opposed to an effect), much like applying a plugin or outboard compressor to a signal.
I don't know what's going on under-the-hood with Amp Compression, but logic tells me it's not quite the same thing. I've read here previously that it doesn't do what we're talking about here 'though, so I checked the manual:
Compressor
This “Compressor” parameter is different from the Compressor effect, as it is a part of the simulated amp circuit. In other words, it allows for completely different sounds compared to compressors that are inserted before (pre) or after (post) the amp module. Distorted signals are not affected by compression; so only clean signals will be boosted. The dynamics of your playing are fully retained, allowing you to go from a crunchy sound to a compressed, clean sound, purely by the strength of your picking. The volume knob on your guitar works exactly as you would expect: for instance, reducing the volume of your guitar will transform a dynamic crunch into a clean, compressed sound with full energy.
Somehow 'though, when I crank it up using driven tones it gives me a "creamier" playing response - a smoother, seemingly-more-sustaining result. IDK why I have this impression given that the manual implies this should only be apparent using clean sounds, but hey, I love it.
The key thing here, I reckon, is this:
But will it last?
I doubt it. You might have got lucky, which is statistically-improbable, but possible nevertheless. Others have reported the same thing in the past, so you won't be the last, but it's a dangerous way to fly. Best to set your AI to clock to S/PDIF when you're using your Powered Head, mate.
Thank you for the update, G String!
Awesome.
