RCA, Balanced, Krell CAST, Status Quo to Nirvana?

Stevecham,
It's good to hear from another Krell owner, especially one with comments on the CAST system. I read the review you posted in 2003 about the KCT pre amp and it was interesting and informative. It just so happens that I took delivery of a new KCT pre amp yesterday. As you probably know it has just been discontinued, as the Evolution 202 has taken it place. I believe I bought the last new unit in captivity so the price was great. Even though I have other Krell gear, the KCT is the only one with CAST connections. I guess I'll have to wait for a future upgrade to experience what you've been enjoying.
Ken

CAST makes perfect sense to me. If the preamp and amp were one integrated system, in an ideal situation they would be connected via a low impedance, high current connection that was balanced. That is the advantage of integrated amps. What Krell did is make it possible for this connection to be portable and swappable between diffeerent Krell components. I have a Krell system, and the CAST connection sounds better across all the typical dimensions we use to describe sonic attributes, compared to the voltage domain, balanced XLR connections.

Herman,
your reply was analytical, to say the least. I either didn't say enough , or said too much, I believe it was the latter.
My reference to the "SOUND" of cables; Single ended gear, pre amps etc. tend to have a lower output impedance and drive amplifiers that tend to have a high input impedance. In this case, the single ended interconnect cable's impedance will tend to add a sonic signature of their own to the sound. This may be why so many audiophiles swap cable brands and types until they get a sound they like.

With equiptment operating with balanced inputs and outputs, usually 600 ohms or less, a low impedance line will have less of an effect on the overall sound sound of the system. Balanced lines , besides offering more gain, they also, as you correctly stated, null out common mode noise.

Herman, I did mean topologies, I stand corrected.

Regarding redundant conversion; We see guys going right from a cd player straight to the amp. Any unnecessary stages that can be eliminated should result in better sound. Balanced interconnects offer help in reducing the sonic signature inherent in single ended cables, but still operate as a voltage conduit.

It seems that the CAST system, by keeping the signal in the current domain , eliminates any voltage to current conversion from the source to the amps output. You certainly are correct when you say that you can only get CAST from Krell. I seems as though they ventured into this design with the thought that it would come a step or so closer to better sound. While they incorporate CAST connection in their units, they also incorporate both single ended and balanced inputs and outputs side by side with the CAST connections. If a person chooses not to use the CAST system, you might say he is paying for sometiing he'll never use.

Cast has been out since 2001 and I've never heard it. It was and is my hope to hear from those who have opinions on single ended, balanced, and CAST connected systems.

the cables null out the "SOUND" of single ended cables

No, balanced cables null out common mode noise picked up by the cables, they still have a sonic signature just like single ended cables.

Both topographies convert from voltage to current and back again, over and over

I assume you mean topologies but I don't think that conversion over and over thing is correct. Could you please explain?

Most amps use stages that are designed to act like voltage sources. They produce an output voltage proportional to the input signal and try to deliver whatever current the next stage is trying to draw. This isn't really a conversion from voltage to current and back.

Current sources like the CAST produce an output current proportional to the input signal and try to develop whatever voltage it takes to push the correct current into the next stages.

I think the CAST system is a viable solution but you are locked into Krell gear since nobody else uses it.