Balanced or RCA?

For that length either is fine. Balanced sounds much better between my amp and preamp.

I agree with Phil that for a 1.5 meter length, either the RCA or balanced cable should be fine. The primary advantage to balanced cables is noise reduction when you have a long run (such as in recording studios). I have used both balanced and RCA 1.0 meter interconnects between my Bryston SP-1 pre/pro and Bryston power amps, and frankly can't hear any difference the two. I ultimately opted for RCA, since they are generally less expensive than balanced, thereby allowing me to get a better quality cable. I have owned Kimber Heros, and think they are one of the two best interconnects in their general price range (the other is Alpha-Core Goertz TQ2, which replaced my Kimber Heros).

You may want to contact both manufacturers, some manufacturers specifically design their gear for one or the other (yet offering both), therefore giving a greater result. I have asked several manufacturers this question and they have always told me what would give the best results.

Assuming your equipment has both balanced and RCA connections, I suggest you borrow one of each cable type and listen. You need to let your ears decide what sounds better in your system and your room. In my case, I decided to go with the balanced connections because it sounded better (IMHO). I have a Rowland Concentra I integrated amplifier and the Meridian 508.24 cd player. Balanced connections are more expensive so this option will cost you more money. Some audio equipment is not really balanced so you also need to check this. Good luck. cheers...

Balanced is better from my experience. I tried the 1.5m RCA and balanced XLR versions of the Transparent Music Link Super XL interconnects between my Krell KRC-3 preamp and Mark Levinson 331 power amp. The balanced XLR version was more transparent, open, neutral, airy, dynamic with more harmonic integrity. The improvement in my setup was quite dramatic. I chose the balanced XLR.