Shane, it is. Basically in a nutshell, with EL34's. However it's still got that 5150 sound to it as well. The EL34's really change the voicing of this amp more than you'd imagine. Typically EL34's don't make that big of a difference, but this I can tell is going to be pretty much night and day if I put 6L6's in it.
I've been playing a lot of my blues-rock stuff through it, using a Keeley modded TS-9 in front, with my ESP/LTD EC-1000 Deluxe (black, dual EMG's), and so far I have found MY tone for my blues-rock stuff. I just set the dials literally exactly as I had them on my 5150 for this stuff and it sounds identical except that this amp sounds more alive and also warmer due to the EL34's. I have been fiddling with metal playing through it, it does it just the same as the 5150...again, warmer, a little more character.
The thing with this amp is, Satch always loved the Marshall sound. Hence the EL34's. You can hear that in this amp. But the GOOD Marshall sound, like, I dunno...but the good kind. Where when you find out that dude used a Marshall JCMwhatever on the album, you were blown away in disbelief - type of tone, yanno?
It's like if you take the EL34 warmth and character, shoved it into a 5150 box, added great cleans, and altered the overall tone just a smidge, you have the JSX. I will continue to stand by my claim that this is merely a really fucking nice 5150 with EL34's. For those of you that claim that it's some whole other kind of amp bla bla...you don't know tubes.
With the TS in front of it, it gets extremely fucking tight. Tighter than I can get my 5150, thats fo sho. Using the Crunch channel, gain on 4, TS drive at like, 3/4, tone at 5, and level at 5/6....tight ass amp. Anybody that has been wanting a 5150, but still isn't sure about it, I'd say seriously look into this amp. It sounds great, price is great...features are great...list goes on.
Sound clips probably tomorrow guys. I don't feel like running my 57 through the MobilePre USB for this. Unless I did direct and used impulses....I'll think about that one.
~e.a