Yes...with the gain setting on low (6dB), when you move through the volume setting, you get finer gradations in the level than you would at medium gain (12dB) and at high level (18dB). So it just gives you the ability to fine tune levels to where you want them. Also depending on the gain of the amp you are using it with, if the power amp has a high gain setting, you can put the LS-26 on the low gain setting and again that allows you to get finer gradations in level when you move up or down the volume setting. The Ref 3 has single gain setting and when used with a high gain power amp for example, even at the volume level set at 1 notch above mute, you may get too loud a level for late night listening for example. So it just gives you flexibility. Hope that helps.
Is there anyway for you to audition the LS-26 vs the CJ pre in your system before deciding? Even if you just audition at a dealer with a system that is close to yours, it may be instructive to get an idea of the sound. ARC's latest offerings (like the LS-26) are very neutral as compared to other tube offerings and you heard some comments above that referred to ARC gear as lean. So it may be that you may not like or be used to this sonic signature (although I don't think it is lean but I have an all ARC system and so the synergy between the pre and power amp is there). I would at least give it a listen (preferably in your system but if not at a dealer) before deciding to pull the trigger. I personally love the ARC house sound but that is my opinion and listening preference. Others have different opinions. Good luck and let us know how you make out. Take care.