I did this one a while ago, but it demonstrates (to me at least) how different a pedal can sound through two different amps that sound very similar without the pedal.
And given the differences in the tone stacks of the two amps, this makes perfect sense, might even be predictable. The MDT has a Tweed tone stack, the HXDA a Marshall-style tone stack. And there are other differences between the two amps in the preamp circuit and the power section.
I have a few dirt pedals that sound very good with the HXDA, but to me, the whole purpose of the HXDA is to use its own gain and not need a dirt pedal in the first place.
I'm not sure it's completely fair to say the HXDA isn't a pedal platform, but like any vintage Marshall style amp, it takes vintage style pedals especially well, and also soft clip ODs. Something that clips bright and hard like that Wampler is of course not what the HXDA will sound its best with, though the controls could be worked to sound a lot better than that recording!
Boost and OD Pedals that I think work very well with the HXDA have been:
Suhr KokoBoost - this is a very clear and open sounding boost that just makes everything sound better.
Exotic EP Boost - emulates the preamp of a transistor Echoplex, the kind Page used on stage to boost his amps even when the echo was off.
Fulltone Plimsoul with small control on soft clip around 8-9 o'clock, and HXDA set to DA, DA, HX. Kind of works like a tube screamer type OD in this mode.
Bogner Burnley for higher gain stuff worked great for me for several TV commercials
The classic combination of Marshall style amp and germanium fuzz, in my case a Fulltone '69 Fuzz, was perfect. Obviously, setting up the amp and pedal to work together is important, but a fuzz-face style pedal is what Jimi Hendrix used with a Plexi, and most people dig his tone.
The Xotic BB sounded very good with it, used judiciously.
Fulltone Robin Trower Overdrive - a very good soft clip, works extremely well with HXDA and was designed for a Plexi style amp
Fulltone Fulldrive 2 or 3 - another excellent pedal with this amp.
Modulation:
Fulltone Clyde Deluxe Wah - excellent wah with HXDA, again, especially for Hendrix or Trower type sounds
Suhr Jackrabbit Tremolo - Easy choice, most trems sound good with HXDA
Eventide H9, various programs, but my fave is the Leslie speaker emulation - great sound with the amp, but I also use some of its wilder effects to good results
Fulltone Deja Vibe - fantastic, as you'd expect, and very easy to get Robin Trower tones, since of course Uni-Vibe is what he used with Plexi style amps in the first place, as did Hendrix.
I also find that my usual panoply of modulation and delay pedals that I haven't listed work great with it. I use various stuff I have lying around for modulation.
Another effect that is absolute
greatness with the HXDA is my Fulltone Tube Tape Echo. Nothing's more classic than an Echoplex in front of a Plexi for those Page tones, as well as some of the Hendrix tones. It's like melting sonic caramel into sonic butter and chocolate.
You'll notice that I mention a lot of Fulltone gear that works well with a Plexi style amp like the HXDA. No surprise there, Mike Fuller mostly creates vintage style pedals that work well with his own Plexi and Fender amps from the 60s. That's what I mainly like about Fulltone gear - it's good for getting certain classic sounds that work with vintage style gear. That's why Robin Trower, Eric Johnson, and a lot of other Fulltone pedal players use it, and of course, Eric Johnson lent PRS one of his amps for the HX part of the HXDA, according to "certain sources."
