Passive preamp recommendation to my system

Definitely worth trying some passive pre-amps like Bent Audio Tap-X and Lightspeed. I disagree with initial post that they are a waste of time and money - completely unhelpful and unconstructive remark although hardly surprising on this forum.

I have enjoyed BENT TAP-X, Placette RVC (and Active Buffered), K&K S&B Transformer, Goldpoint passives. The best of the lot in an ideal set up has been the Lightspeed Attenuator (LSA). As Clio9 mentions, not all situations are ideal in terms of impedance (usually, but not always ok in terms of gain) and you would need to use a buffer - like those mentioned by Clio9 - First Watt B1 and The Truth, or one of the above mentioned along with something like the Burson Buffer. These solve a problem, but the best passive aproach is with no buffer when you don't need one. Your setup is borderline and you don't mention the lenght of your IC cables from passive to amp - another consideration.

I don't know about Stringreen's comment, other than I know many folks that have used several 5-10K preamps that swear by passives - so not a complete waste of time and money for some - certainly not for me.

The cables from amp to preamp is about 3ft

That should be NO problem in and of itself with just about any cable maker. I think Anthony (Clio9) main concern is the input impedance of the KRELL, if it is 47kohm, that should be fine and the output impedance of CD/DVD player. If you want to try a decent active tube linestage at your price point, you may want to look at the Decware CSP2+ or the Mapletree Audio. I thought the Mapletree was extremely good compared with the Lamm/CAT/Joule preamps I owned - it certainly did not embarass itself, though not in their league visually, it is a small, handmade product, but desinged by a retired Professor of electrical engineering in Canada that knows a bit about circuits:)

I would agree with a Krell amp it is a waste of time and money and good amp.