Ok even as a splawn dealer, I have opinions! I had 2 JVM's the otherday, and opened one kept the other in the sealed box to sell, here are my thoughts.
Overall features: The JVM trumps the Splawn in features, JVM however trumps most amps in features, its footswitch w/ three switchable modes per channel ought to show scott an idea to use. It would be great to see scott offer the multi-tap use for the gain channel to switch gears. However, that in conjunction with midi and 4 independent channels with 3 dependent modes per channel is an incredible array of tones. The reverb was nice too, I however found myself only using it on the clean. It seemed to be an endless tonequest of an amp. The splawn however was limited on these features, as are most amps out there. JVM wins in features
Volume/Power amp feel: Both amps being mocks of old/new marshalls in tone and feel seemed to respond very similarly in the power section, better with volume just as expected. Both are of the EL 34 family so I guess it just makes sense. The splawn to me however is more natural in the higher volume stuff, I liked the JVM at the lower volume stuff though... Splawn wins at the better power amp feel and better tone w/ volume, JVM is winner with the low volume tones
Clean tones: Even though Splawn has updated their cleans... The JVM took this one by storm, the reverb made the amp extremely lush and full sounding and filled the room nicely. The splawn had a little grit on it and wasn't as "pretty" of a clean. It was a little dirtier and rough, cool but not a clean clean blackface style sparkly clean we think of when CLEAN is spoken of. My vote goes to the JVM here
Low Gain tones: The JVM and Splawn both rock at this. When cranked through a good cab, SPLAWN hands down. When at a lower volume and a touch of reverb is added, JVM no contest. They all have that old AC/DC thing going on that just rocks the house, these are my personal favorites of both amps. Just wow... High volume splawn wins, Low volume JVM wins
Mid Gain: This is where the Splawn starts becoming the better amp... In the hi-mid frequency dominated mid gain. The splawn has this done especially when a little bit of volume can be used too. The JVM has the features that help it pick up points where it starts to lack from here. It just doesn't sound as good as the splawn. You can start to hear the quality differences in the tone here. Splawn is winner, JVM takes some of the pie though in a bedroom setting though, again better at low volumes.
High Gain: Ok, now is where I am gonna catch some heat from people. Everyone has their own opinion and I do not mean to start a flame war or anything at all so whatever! JVM has some really JCM 2000 vibe going on here, cool but not the marshall you think is going to be coming out of it. It kinda drops the mid projection just a bit. Almost starts pronouncing some lower mids that just don't come to mind at all when you think of marshall, also the gain on OD1,OD2 on red are over the top. Low volume JVM rocked, a little higher it got a little noisy for me and I wasn't too keen on the gain structure.
JVM @ low volume
Splawn @ High Volume
Overall: Wow, two absolutely great amps. The JVM with all its features and midi just wow! The Splawn with its great tones and just being a great amp alltogether was great too. Truly a battle of two great amps with no real winner at all.
My vote: Splawn at high volumes and for the more purist type great gig amp tooa
JVM for some lower volume people and the cover band guitar players that need it all.
Both are great amps that are both reasonably priced! A true priviledge to have and to have played both of them!
Don't hate me!
Josh