My commercial HX, a Rancilio S26, is modified to do adjustable preinfusion (in time and pressure; i.e. none at all, or PI for 5s on 4bar, or 8s on 2bar, etc). It's also modified with a thermocouple under the showerscreen so I can read the water temp as it hits the coffee. But, I can never make it produce shots as good as my Peppina, actually, not even close. Same goes for my stock Caravel, can't touch my Peppina.
My Peppina is modified with a TC and a pressure gauge in the brew path. So, basically, I can do full, true, measurable, but manual, pressure profiling on her. I also have her on a dimmer so, with help from my TC, I can make her do declining, inclining or stable temps during a shot. That said, no matter what I do with her, she produces the best shots I've had at home or elsewhere; mind you, I've had the least experience with her compared to my other machines.
I prefer using my commercial HX, but I don't know how to make it produce shots as good as the Peppina's; no matter what I try, it just doesn't work. Oh, neither can I ever make my Peppina produce shots similar to the HX's; even with no preinfusion and full 9bar pressure on the lever during the whole shot.
How would I describe her shots? In general, thick, flavorful, balanced, sweet, crema laden, out of this world. The caravel's are usual much more mellower and lighter, just worst. The HX's(even on 8bar) are usually pushier, less flavorful, just worst.
I want "it" to be my technique, so I thought of asking here if someone knows how I could make the HX produce as the Peppina does(hence posting in the Tips and Techniques forum), but I have a feeling this isn't a question we know the answer of. Instead, I have another question: if you have/had a Peppina, were you ever able to make another machine of yours make shots like hers?