A few years ago I connected an extension cab to my Flextone III and dialed in the ping pong delay. I was hooked instantly and I mean seriously hooked. I might have given up on this amp a long time ago if it weren't for that amazing stereo delay. The challenge with this amp was always about how to transition from a clean tone to crunch or distortion without it sounding fake. Whenever I switched channels the reverb or delay would just cut out abruptly and then the new channel would have entirely different tone, which was just weird. I wasn't ready to walk away from that stereo delay though, so I kept trying different stuff until I finally worked it all out.
I no longer use the FBV controller at all and I just use one channel, the Line 6 Clean channel.
I use the Flextone's built in reverb and noise gate along with a very slight slap delay and this is my clean tone.
I connect a Line 6 M13 effects unit to the amp's stereo effects loop using the multiple cable method.
(I made a cable snake and marked all cables so set up takes 20 seconds max).
I have a 2 channel overdrive pedal that sits between the M13 effects send and the Flextone input.
The result is an endless selection of absolutely incredible stereo effects along with great clean, crunch and lead settings that sound like they're coming from one great amp. I'll repost with a properly recorded YouTube demo soon as I get a chance.
Now the Flextone is discontinued and Line 6 seem to want to distance themselves from this product, but for anyone looking to build a great sounding STEREO rig, I don't think there's an amp on the market that comes close to this.