Do long interconnects degrade sound?

I agree with Cwlondon, your Krell should drive 50 feet of low capacitance interconnect with no problem. If you want to be sure, check the specification of the chosen interconnect (at final length) and call Krell with the data.

Most high end cables are so low capacitance that even 50 feet would effect highs (roll off) only above approximately 100 Kh. It's even less of an issue with balanced because the output impedance is generally very low (600 Ohm), making the load even easier.

Eldartford, probably should have said

600 ohms or less

As for the Krell, here are the specifications for its RCA outputs. No balanced outputs on this model, but who cares with that low an impedance?

Sidebar 1: Specifications

Description: Solid-state, remote-controlled, stereo integrated amplifier with 5 line-level inputs
1 balanced, 3 single-ended
1 single-ended tape loop
1 set of single-ended preamplifier outputs.
Power output: 200Wpc into 8 ohms (23dBW)
*Output impedance: 0.17 ohm*

Even inexpensive cables, such as sold by The BlueJeans Cable Company ($83.00 for 50 Ft. RCA) is only 17 picofarads of capacitance per foot.

The point is, it's what this gentleman needs to keep peace in his home. I have a pair of 60 foot BlueJeans RCA cables in my HT system and it's OK for that use.