Rogue 100 dark

this amp has great nos tubes including the mullards you speak of. I think my setup is fine. At least it is using the cary ss amp. Power is not the issue here. It just lacks the subtleties in the mids. i am using it with the switch in the down position. I have not tried it in the up position. I'll try.

I think up is Ultralinear and down is Triode. 
The ST100 is quiet for a tube amp. It is a pretty neutral amplifier and won’t be syrupy sweet. The midrange is natural and glare/grain free. I had great results with Gold Lion12AX7 and 12AU7. Overall the “base” ST100 is a great value. Especially once you change the stock JJs out for something better. 

ultimately I am not satisfied with the Rogue. It is not the quietest. Rogue makes nice products. this amp just lacks the tubey sound. Maybe I should post asking for a 75 wpc tube amp that will give me that tubey sound.

Maybe I should post asking for a 75 wpc tube amp that will give me that tubey sound.

I would recommend a Prima Luna amp with EL-34s or maybe 6L6 tubes. That is where good tube magic happens. I have EL-34s in most of my tube amps.

Edit: The EL-34 only puts out about 22 watts each but I have not had issues even running hard to drive speakers. 

Yep that’s the Rogue tube amp sound. The midrange is a bit dry, certainly more than you’d expect from tubes. Sometimes they can sound a bit bright, as shipped with stock tubes (depending on what those are - it’s changed over years). This doesn’t change as you move up the line. On the plus side, their bass, dynamics, and impact are awesome! And these aspects further improve as you move up the line (all the way up to Apollos, even if you don’t need the extra power). You can definitely make these amps sound warmer & sweeter with Gold Lion KT88 outputs (this helps the midrange a whole lot) and NOS small tubes, but the reality is it’s never going to sound exactly like a classic "warm & wet" tube amp (e.g. vintage EL34 or 6L6GC tube amp sound).