I did a brief test of the SV20 Head and Origin 20 head this morning, I plan on comparing more over the weekend. Note - this is with the SV jumpered and input into the Top left (high gain, bright?) side as is considered "normal" in a '70s / Rock / Led Zep context on 5-watt mode and the O20 in middle (3 watt?) mode At this stage, I think the Origin 20 is 90% (possibly more) of the way towards the SV in terms of similarity of tone. I consider the Origin 20 a bright amp but surprisingly the SV is slightly brighter at lower gain but less bright/warmer at a higher gain (is that the bright cap working?). The SV is definitely louder and less manageable than the O20 which is VERY flexible with its 3-way attenuation switch. I also plan to test the O20 direct out into my Helix with Cab/IR's only. If this works well it is a REAL advantage of the O20 in that it can do this without a speaker load or sound. The SV has a slightly more direct/ I am part of you, connection with the Amp, which is VERY unforgiving but enjoyable (very much like a Tele is revealing of your playing). I suspect that if I had both to compare pre-purchase and bearing the near double price in mind, I would have stayed with the O20. However, knowing you have a "Plexi" and the direct-to-hands feel is pretty compelling. I will post thoughts further if anyone is interested? (I'm hoping for a get-together jam with our drummer tomorrow night, and will take both).