Which is the better way to split an audio signal?

(1) Purchase a quality Y adapter/connector which is placed in the pre-amp RCA out - and then run 2 separate quality IC's from it?
Or (2) use a quality IC with a built in Y (one connector splitting to 2 legs)?

I need to split the signal coming out of my older pre-amp.
I wish to add a subwoofer to my system which has no bass
managment. So, one side will feed the power amp to my 3 way speakers, the other side will go to a powererd subwoofer (which has a built in variable cross-over and volume control). I'll have only one subwoofer so I need to feed each of the 2 channels into it for a mono sub bass.
Thanks for your help,
Not sure if there really is a quality splitter cable (???). If there is, you are still stuck with that brand. So I would opt for the split RCA plug instead and then choose good cables that match your components. Cables are very component specific IMO.

For some subs you can get a crossover that goes between the preamp and power amp (its own splitter). Check with that manufacturer or dealer. Secondly can you run the sub using a high-pass connection? This is where it runs off the speaker terminals on your power amp.

There may be room inside your preamp to add a second set of RCA jacks for outputs. Wire them with the shortest piece of good conductor and Wonder Solder close to the present set.

While you are in there, upgrade with Cardas or Vampire connectors. You would improve performance in the process. The "Y" connector will cause you to take a hit in quality and probably wind up costing as much as my suggested upgrade / solution.
A number of high end cable manufacturers can do custom configurations like splitters and Y's. Obviously, you're going to have to pay up and wait.

Your option #2, using a Y cable, may offer a purer signal path by eliminating one interface/connection (between the splitter and the IC's) that would exist with option #1. Theoretically, such interface/connection points could slightly degrade the sound. HOwever, I have used option #1 splitters with no observable difference in the sound.

Practically speaking, option #1 gives you significantly more flexibility if you ever want to change things around in your system. For example, if you went with option #2, you would have to get a Y cable with one leg perhaps 1 meter long to connect your preamp to your basic amp and the other leg would be perhaps 4 meters long between your preamp and your subwoofer, to provide for optimal placement of your subwoofer. This could limit your options if you ever changed your mind about subwoofer placement.

Finally, while I would recommend using high quality IC between the preamp and the basic amp, I don't think you need an IC of as high quality between the preamp and the subwoofer, given the nature of the signal. A Y cable would presumably be the same for both its legs; you could save money on the subwoofer leg if you used a splitter. Best of luck!
Another option might be to put the splitter at the amp. Thus running your good ICs to the amp and then another set of ICs to your Sub.
If your Subwoofer has an adjustable level control , you can connect a interconnect from Tape out from your Preamp to Subwoofer.
Thanks all for the suggestions. The tape outs sounds like
a great idea since I wouldn't actually be splitting the
signal. If I ever add a tape deck, then maybe I'll try
splitting the signal at the amp end.
The tape out has no volume control. I'm curious to know how you can control any increase in the pre-amp volume which is now not supplied to your subwoofer through the tape out !?
Have you already purchased a sub ? Many subs (REL, ACI) will connect to the power amp speaker terminals. This avoids splitting the signal. Many people believe that this is the best way to go for a music-only system.

I don't think the tape-out solution will work .... you would have to constantly adjust the sub's volume to match that of the mains, since the tape out is constant level, and not affected by the pre amp volume control.