I just got some RTA 15tl's for the fronts on my 7.2 system. Naturally, I'm in love. I decided to set these to large to team up with the powered subs (It's a big room-- 25 x 33, 12' ceilings). My Yamaha receiver HTR-6160 is decent, but I really want to make these speakers sing, and take some load off the receiver as well. So I pulled out a couple old amps (Hafler 120 watt/channel, Crown 300 watt/channel --both at 8 ohms) to use with my receiver's pre-outs to drive the 15tl's. Problem is, it's damn quiet. Way quieter than just keeping my fronts through the Yammie.
Just to test my amps, I ran a cd player straight into them. My 15tl's sounded great. So I called Yamaha and they said I need a a pre-amp between my yammie pre-outs and the power amp. This doesn't make sense to me--I thought the receiver was already a pre-amp, and the Crown and Hafler already have volume knobs on them. The crown even has two input levels settings in addition to the volume knob: 1.4 volts AND +28db. Neither are loud enough.
I've scoured the internet for info on receiver pre-outs--never saw anything about using a pre-amp before the power amp.
Thanks for all the help!