I agree with Jim above, the 336 has plenty of body and substance. I use a BAT vk51 se preamp with my 436's (previously owned a 332) and Mac 501's and its super. To me your issue is the Linn, which I feel would be the lean component in your system.
Upgrade from Levinson 335. Which amps?
I can describe the sound from the current system as open, clear, and airy. I think the sound is pretty close to neutral, but some might say the sound to be a bit on the leaner side. I would like a bit more body and substance in the sound, maybe at the expense of some of the openness. I prefer SS over tubes, but I'll consider both. Some of the amps I am considering are:
Pass Labs XA-30.5
Spectron Musician III SE Mk2
BAT VK-75SE
Rest of the gears: Linn Unidisk SC, Focal 1037BE, no preamp.
Pass Labs XA-30.5
Spectron Musician III SE Mk2
BAT VK-75SE
Rest of the gears: Linn Unidisk SC, Focal 1037BE, no preamp.