I recently bought a BA-F1 power amplifier and am amazed at its clarity. It didn't come with a user manual and I'm not sure of the difference between the AC and DC input jacks. This is my first power amp, so maybe these options are common to all. What do I need to consider when choosing which input jack to use? Anyone know where I can download a user manual? I couldn't find one on this site.

The DC is a direct DC-coupled input to the driver board, and the AC has a couple of caps in the signal path to block DC.

The DC input is preferrable, but only if you are certain that your preamp is not ouputting any DC on the line.

And the OLOF rule for the amplifier applies, especially if you use the DC inputs... amplifier On Last, Off First.

if my preamp outs (on my AU-717) are presenting voltage to the DC input on my BA-F1?? Can I do this with a multitestor? ....and if it is what can I do about it?

You can measure with a meter...but you'll likely need some boogerized old IC cables to cut up to do it.

The 517 and 717 both are cap-coupled at the preamp outputs, so unless the original caps are leaking, it should not be putting out any DC from the preamp jacks.

...back in April (and she sounds fine) I think I'll be cool.

Rgr that...

(yeah, I led you to it....) :)

...I was reading a thread from last year which touched on driving a sub with a configuration similar to what I want to do. (I may, by the way be sending you a BA-F1 for you to check out...I'll let you know)
...anyway what I want to do is use my AU-717 to drive my JBL's and use the 717's preamp outs to go into an active crossover (any model recommendations on the xover? ...something like the Behringer CX2310 perhaps?) and then into the BA-F1 to power the sub. My question is this: How do I connect RCA preamp outs to a behringer crossover and then out of the xover into the BA_F! Im haven"t found any adaptors>>>?

thanks

The BA-F1 is a great amp, but it's a bit under-powered for a sub amp, unless we're talking about a small sub with low power handling.

Most subs nowadays have their own plate amps, and their own low-pass filters built-in, so my critiscism of your plan is not enough power, and a Behringer is overkill for a sub crossover or low-pass filter.

...infinite baffle sub...so all I need is to filter out the high frequencies before they get to the BA-F1...I considered plate amps but would rather use vintage...if the Behringer is overkill, what do I use for a filter?