To start I must clarify that this is not another "KPA vs Axe-Fx" thread...
I have been an Axe-Fx Ultra owner for the past year and half. While I have been decently satisfied with the battery of effects that it includes, I've had a love/hate relationship with its amp models.
I play ambient/prog/jazz-fusion stuff, using vintage guitar synthesizers (Roland's GR-300 and GR-500), plus other instruments and devices. My main sound is based on a 1971 Fender Vibrolux - clean Fender sound, silverface, modded to blackface specs. It is a wonderful amplifier.
The first thing I did when I got the Axe-Fx Ultra was to attempt as close as possible to replicate my Vibrolux. After two days of frustration I had to give up because the sound I was getting was thin and plastic. In the end I resigned to live with it. However, what the Axe-Fx provided was the capability to build a specific rig for each of my instruments.
I read about the KPA and the possibility of replicating my Vibrolux in stereo has now become a strong option. However, I want to integrate the Axe-Fx Ultra as a dedicated effects unit, while keeping the KPA as the amps' source. This is where I would like to have some input as my setup is rather complex.
Currently I run the Axe-Fx Ultra into a Metric Halo 2882 interface via s/pdif. The 2882 interfaces with a Macbook via firewire, where I run Mobius, Ableton Live, plus other synth plugins. The output goes into a pair of Adam A7 monitors. Both guitar synthesizers have their signals split; the guitar signals go to the Axe-Fx while the GR-300 goes to the 2882 where it gets effects from its 2D card. The GR-500 has its own outboard dedicated Eventide stompboxes and from there it goes also into the 2882. Mobius is the global looper, I can create loops from each sound source independently allowing me to switch guitars in real time.
In addition, I have an outboard "tabletop" board of synth-like pedals which are tweaked real-time as I perform. This tabletop is right now connected in front of the Axe-Fx as its effects loop only accepts line level units, not instrument level devices. This is a bummer as the Axe-Fx can incorporate the effects loop as a separate effects block, to be switched on and off as needed. Due to the impedance differences, I cannot achieve this.
Based on the above explanation, I would like to use the Axe-Fx Ultra as a slave unit of the KPA. I would like to use the KPA's s/pdif in and out; I read the KPA's manual and the auxiliary output replicates the guitar output so I could connect my tabletop board there. What I'm unsure is how the KPA would react as ideally the Axe-Fx should be connected into some "digital effects loop" between the KPA's preamp and power amp/speaker section.
Another idea is to plug in my guitars into the Axe-Fx, then s/pdif into the KPA, then s/pdif into the 2882. But again I'm not sure how it would sound; if I'm running long reverbs on the Axe-Fx and I run a distortion amp on the KPA it may sound horrible.
In sum: I believe that the two units working together may create a super-powerhouse. There is strong potential for creativity and beyond. I appreciate any comments if you have already tried out this combination.
(I have been reading the threads "FX Loop on spdif" and "A question about the functionality of the KPA with multiple external effects units, using spdif" with interest, however no concrete replies so far)
