Connecting a sub to amp pre-amp outs?


I know this is a painfully ignorant question for most of you guys, but bear with me. I have never had a sub before so... There is no sub out on my integrated amp, but I do have a pair of pre-amp out jacks. Can I connect these directly to the low level inputs (L and R) on my powered sub? The sub manual says I can do that, but my Arcam amp's manual doesn't say anything about that--in fact, the manual more or less says that the only time I would need the pre-amp outs is to add a power amp for bi-amping. Right now I am using the second set of speaker binding posts on the amp to run regular speaker cable to the high level inputs on the sub. What will I gain/lose if I can go from the pre-amp outs on the amp to the low level inputs on the sub?
salby6
Similar question. I have a couple preamps that have 2 sets of outputs. I usually run 2 channel and run one set of outputs to my sub and then run another set of interconnects from my sub output to my amp. Can I use the other unused preamp out to just go to my sub? So one output to my amp, the other outputs just to my sub in? 

If I've read these comments correctly would that just run the speakers at full range instead of using the subs crossover control? 

Using Vandersteen 2CE Signatures which are reletively modest on the low end.


Yes, this should work fine, but take time to dial in the sub level again by ear, as you had done previously using the other connecting cables.

The notional benefit is that a lower-level (should be less distorted and less lossy) signal is passed to the subs, although this may be canceled out if the sub’s amps are themselves crappy.

You still need to low-pass the sub (use its crossover) unless there is some way to do this in your amp. I doubt it as otherwise this would be described as "sub-out" connections, not pre-outs. If you ran full-range, then the sub will be amplifying a full-range signal, causing overlap and distortion beyond the driver's useable range. Probably start around 100hz and keep going down.