I did get some answers from our engineers and they are summarized below:
Regarding idle power consumption: less than 20 watts.
Regarding power consumption while playing, it's difficult to come up with a meaningful long-term number because HT high-energy low-frequency information is present only infrequently. With steady-state test tones you can get pretty high current draws (on the order of 25A (3kW), which will overwhelm a typical household circuit if run for very long. In practice with real program material, the duration of these high current draws is short and can be supported by a typical household circuit.
If you want to use a line conditioner, we would suggest something rated for at least 3,000 watts. We honestly do not see much value in the conditioner, but it's your money.
It is our recommendation that a Fathom should plug directly into a wall outlet and that outlet should not be switched, and ideally its circuit should be shared only with low-power consumption stuff say, a few hundred watts, although we've been able to get away with more than this. Incidentally, the AC outlet iself should have its wires connected to the SCREWS on the back, not "back-wired" to the push-in holes. Builders often don't bother to do this correctly because they are lazy... and this zero-dollar mod can have much more benefit than a line conditioner.
Regarding inputs, all four of the inputs are summed together - any and all that receive signal will contribute to the output. So, in this case each of the two subs could have one XLR input from the LFE source and one (RCA ?) unbalanced source from the preamp (NOT to the other XLR through an adaptor!) connected at the same time. What we don't recommend is applying signal from the same source to two different inputs because it's redundant or applying signals from two different sources at the same time, which is silly and might damage the source units. Just make sure whichever source you're not using is turned off. Do this at your own risk.
Hope that helps,
JL Audio, Inc.
Originally Posted by The Bogg
Couple of questions about the Fathom 113 for anyone including Manville:
1. How much power (watts) does the unit draw from the wall at idle and at full output? Helps me decide what rating line conditioner to get.
2. I had hoped to connect a pair of subs to my stereo and home theater. My home theater front speaker output goes through the "bypass" mode in my stereo preamp whenever I'm watching movies and this stereo preamp uses balanced outputs to the amp driving my main speakers. I had planned on connecting the pair of subs as follows:
1 balanced output from the LFE channel to each of the subs (my processor the Anthem D1 has 2 balanced mono outputs). Connection between my stereo preamp to the balanced inputs of each sub using an adaptor. I just noticed in the manual that it said not to do that. Is it really a no-no? If I take the unbalanced output from my stereo preamp into the unbalanced output of the sub will it sum the balanced and unbalanced inputs? The manual just says not to use both unbalanced and balanced at the same time.
I'd appreciate some answers from anyone who knows.