With all of my amps in the past, I've been a 10 on both volume and tone knobs on the guitar. With the DSL20HR, I've had to run the tone knob between 7 to 8. And the amp was still too bright in the 2 to 4 kHz range. Swapping to the Eminence Governor has already been an improvement in that range, before breaking in. The amp is good. It just needs some understanding and tweaking. Keep the treble and presence in check and don't go over 5 on the gain knob.
The HX seems to accentuate the lows and mids more making it sound thicker so I end up turning the treble higher on the amp than I used to with my old pedals. So the Amp settings end up being closer to what you normally expect. Plus you can quickly save custom banks of patches for seperate guitars if you have a significant tone disparity between say a bright fender and a darker short scale like a les paul. I mostly got it for convenience, being nice and tidy. But I noticed it really balanced the DSL20 EQ out.
Just wanted to update this thread. Bought an EVH 5150 III 50 watt head. I A/B'd it back to back with my DSL20HR. Short answer...I'm selling the Marshall. I've been a Marshall guy for 20+ years, but these new DSL's are just harsh and fizzy. Even the bigger wattage DSL reissues. Not trying to trash them, but that's just my opinion. I used to own a DSL when they first came out back in late 90's and it was my gigging amp for a few years. Those were actually good.
I'm trying them right now in a 2-12" cab. The ET65 and a Retro30. I think the Retro30 will replace the V30's and sound much better, we'll see.
the 5150III 50w is an amazing bang for the buck... I have one and I think I'm never not going to sell it.