Short introduction: I own Helix LT and I love it to bits. I am, what you could probably call an average guitar player nowadays. I started playing 3 years ago, so I am relatively inexperienced. I play every day for my own pleasure, mostly blues and funk, and I do not gig. After I got helix I sold my tube amps and pedals (this is another typical thing about me, I think I know more about gear than actual playing the instrument, damn you YouTube!;-) ). Helix takes 10x less space, and my 'studio'/room does not transform into a sauna, as it was while playing tube amps. I play through JBL LSR305 studio monitors, but I have to admit that although the sound is great, it does not feel like playing with an amp in a room. What convinced me to sell all my analog gear, was how good the Helix works with my headphones (Sennheiser HD 600), plugged directly into the Helix. I can play along songs, and backing tracks without any hassle, it sounds great, and I get good warm feeling when I hear myself playing alongside SRV or BB King. Playing through headphones feels really liberating, because I do not have to worry about disturbing my wife and my neighbours, I do not feel self-conscious about my playing, and I practice much more.
Now, to the topic. I did not have any problems with setting up my Helix with two JBLs LSR305. For me, it sounds close enough to the tube Marshall and Fender amps that I sold. However, initially I had a lot of problems with setting up Helix with my Sennheiser HD 600 headphones. There was only a single CustomTone patch that worked for me with the headphones, called SRV Sauce. After close examination it turned out that it was because it was set up so that; 50% signal went through a guitar cabinet simulation, and 50% went through a loop that bypasses it. I love a clean blackface sound with a lot of treble, and I used to set up my Fender amp with treble at 8-10 and bass at 1-3. I found that for me; mixing a direct signal from the amp model in Helix, with the signal passing through the cabinet simulation; is the most important setting, that makes playing through Sennheiser HD 600 really natural and amp-like. This is mostly for clean/crunchy sounds (not for high gain), with low output vintage style pickups (both single coils and humbuckers). It sound much more natural, and amp-like, than when I pass 100% signal through the cabinet simulation, which sounds very muddy.
My question is: is this because the headphone amplifier inside the Helix and my headphones work as kind of a cabinet? From what I understand Sennheiser HD 600 are not real monitors and they colour the sound. Or is this method more similar to what Nile Rodgers did with plugging straight into a desk?
Sorry for the long post.