I mean sort of. I always felt like the the JC-120 was a pretty darkish amp as is, compared to say a Fender or Vox. I personally think the chorus on the VHX is pretty good, but it’s still a Diezel with a chorus (i.e. Dark). I haven’t played a VH4 so I can’t compare which one is darker between the two. However, I have played a JC and I’d say the VHX is darker between the two. That being said, I personally think the clean channel on the VHX is spectacular. It’s dark and glassy. Opposite tonally of a great Fender but just as beautiful. If a Fender dissipates into the air, then a Diezel sinks into a crystal clear lake.
After playing around with it, and comparing to sound demos and such, the VHX sounds to me like it was designed as a VH4, then from there they developed tone shaping options to be able to get in the ballpark as the other Diezels. It’s not the X-Bert or the X-gen. It’s the VHX. All of its voices sound pretty similar, but there are noticeable differences. The voices don’t suddenly get you a Marshall or a Fender sound, it still all sounds like Diezel. I believe there’s 32 different tone options: Each of the four channels can switch between ‘Vintage’, ‘Early’, ‘Classic’, and ‘Modern’ voicings. Channels 1 and 2 have a bright switch, and channels 3 and 4 have three different subvoicings within the main voicings. Among the main voicings, ‘Vintage’ is the chewiest/thickest, while ‘Modern’ is the tightest/clearest, with the other being something of a linear gradient between those two.
The FX are good. They sound great, but the controls are more limited than what you would find in the boutique market. Imagine the standard version of each FX type, with some modern updates. Look up the manual if you want to see what to see what controls you have for each FX. I use them constantly, but they haven’t replaced my board. Ironically, I think their on-board Reverb and Delays are fantastic, but since those are the FX I’m pickiest about, those FX are the ones I prefer my board for.
If you’re not interested in the tone shaping, or the on-board effects, then I don’t think you’re going to get anything much different than what you’ve already had in the VH4. If you didn’t like how dark that was, then the VHX probably isn’t going to sound much different in that regard.