Glad there’s another person who has a similar setup to mine
the difference is I don’t have the Sbooster mod so I’m still using the standard internal PSU. I like the LEEDH volume, as it makes the soundstage wider, I can hear better instrument separation, and it doesn’t feel thin at all. Perhaps tighter bass control can give the impression of “thinner” sound, but to my ears it retains the full bodied sound. Bear in mind that I don’t have the Sbooster mod so this can also play a part.
The Manley preamp really elevates everything, but the most noticeable improvement is the expanded soundstage and very euphonic & lush midrange. The 300B tubes really do their magic here. I’ve switched between the direct and transformer mode, and prefer the direct sound (transformer is what usually colorized the sound of tube amps/preamp and yes, on the Manley the sound becomes too lush and gooey for my taste). It retains the speed and clarity in direct mode, I do hear more sparkle up top and weightier bass notes, but everything flows more naturally, not a single hint of harshness. Without the Manley, it already sounds natural but this really takes it up a couple of notches. Do note that it’s not common to have 300B tubes in a preamp, only a handful of preamps use them. I may do some tube rolling in the future as the new production WE 300Bs are already on my radar while the 6SL7s and 5AR4s could be rolled as well.
With regards to the gain, I use high gain and max volume on 13R, low gain on T2 (high gain if listening to my SR1a). Manley’s volume is set at 12 o’clock position, and the overall volume adjustment is done through Lumin’s LEEDH prodessing.