Hi. I need help to choose preamp for my system.

Depending upon your budget and your desire to buy new or used and your desire to match/not match your amps, etc....I'd suggest Classe CP-500 or CP-700, SimAudio P7 or P8, Krell KCT, Krell 202 and others.

I would think the Krell pre would work really well with the Krell amps.Just a thought.

From my experience, Sonic Frontier is a great match for Krell. Haven't auditioned the latest Krell 202 but was never a fan of Krell preamps.

I had a Krell KSA100s with SF SFL 1 and SFL 2. FPB300 and FPB600 with Line 3/3SE+. Line 3 has a very low output impedance for a tube preamp so it will work with a SS amp.

IMHO, I would buy an used Line 3 for ~$2K and get the SE+ mod from Chris Johnson @PCX. I wouldn't waste $$ on a SE ...

Line 3SE+ also benefits from tube rolling. My favorite is Amperex Phillips SQ e88cc and Ediswan CV5065's.

Thanks everyone for the input. My question is how good is Sonic frontier line 3 on bass vs SS preamps like Krell, etc

If you choose the Krell pre-amp to mate with your Krell amps, I'd suggest A-B'ing balanced versus all-CAST. Anytime I've heard Krell gear, all-CAST is the best sound option.