So, I know the amp more now, and it's by far my favourite amp I've ever owned - very different from a DSL; this is where your classic late 60s and early 70s sounds are (as long as you have pedals...). I always loved my Randall RD, but the OD and gain was all in the amp, pedals were a waste of time - this Marshall Origin amp is the polar opposite.
The amp does sound good at any volume, it can be a bedroom amp on the low and mid setting - I prefer the 3w mid setting as you get more air, space, everything; that's where I will stay for most of the time - in my humble opinion, a 10" speaker 3,4,5 watt amp with volume and gain controls is the perfect 'bedroom' amp; I kicked it up to 20w for a short while (it's 2am here, and I'm in an apartment), and it was fantastic, better in every way, amazingly mind blowing, but not needed for home practice (it'd be great to gig with this amp at full volume though).
Unlike other tube amps I've played, the wonderfullness is not in the pre-amp - the Marshall likes the master volume up to drive the power tubes (again, the polar opposite of my small watt Randall amp).
Now, I have tried the amp and the tube screamer and the Catalinbread Rat/Tonebender 2 - just touched the surface; there are so many sounds here, and I'll try to share with you the voices.
The amp sounds good clean at 60db, but you need the SG to start pushing it because the special doesn't quite have enough oomph (for my liking) although you get nice chimey pop sounds with the special . This amp has surprisingly lovely cleans and pre-breakup sounds. You need plenty of volume (too much for 'bedroom' use) to get to break up and classic rock, early metal. I know you lot love Fender cleans, but this Marshall has a good clean sound (lacks reverb though...). This plexi style amp is soooooooo different in character to a DSL (which also sounds great, but has completely different characteristics).
A note here: I have the Origin 20 and my Yamaha THR10, and playing blues/light rock at 60db, as long as I put delay and reverb on the Yamaha AC30 setting it sounded good, not as good as the Marshall, and the Yamaha is $300, but it really was decent to play alongside the Marshall - lacked presence and thump and many other things, but the Yamaha THR10 is a good versatile amp, by the way.
So, obviously, I put the MIJ TS808 online to push the amp and it was really good. It didn't blow me away, probably needed another pedal (I have more coming tomorrow...) to get the classic 60s/70s sounds, but it was very pleasing. I now understand, like I have never done before, why the tubescreamer is such a great pedal. I suspect, tomorrow, when the pedal I bought to put in front of it comes, the TS will sound even better - at the moment, by itself, it's a bit on the light side at the volumes I am playing at, but the amp has the boost setting to help out (I will probably leave the boost on all the time because it sounds great).
The Catalinbrad RatKiller is a pedal I have wanted for a long time, so I was kinda worried that it might let me down. It's the best pedal I've ever owned (ok, I can only put that in perspective with this amp); fuk me, it's good. It goes from classic 60s rock (does Led Zepplin perfectly) through Sabbath and Metallica to stuff like the Pixies and Smashing Pumpkins - it is amazing (for the sounds I like) on this amp - my friend was also blown away by this pedal.
If I could only have three fuzz/distortion pedals then I'd get this amazing Catalinbread Katzenkonig, Wampler Velvet Fuzz and the MXR script Distortion+.
This amp loves, and needs, pedals, like nothing I've experienced before.
At the price, it's stupidly cheap. I now know that I'm a Marshall Plexi guy.