Hi, I'm new here. I'm also in a similar situation. I'm currently running an Onkyo TX-SR805 (130w x 7) with Infinity Kappa 7 Series II (89db efficiency) in a 7.1 setup. I might upgrade to the Kappa 9.1 or 8.1 if I ever come across them on CL. I'm tempted to buy the Outlaw 7700 especially since it's on sale. From what I've been reading in this thread, I won't notice much of a difference? If there's not much difference, why would anyone consider getting separates instead of a receiver? Why would anyone buy a 200w x 7 or even the 300w x 7 amp when a receiver at less than half the price of separates produces a similar sound? I don't mind upgrading to separates and a more powerful amplifier if the money I spend will make a difference. I just don't want to spend $2500-3000 if I'm not going to notice a difference. Any thoughts and opinions would be appreciated.
When comparing good amps to good amps, differences
should be minimal. Some people seek out those minimal differences and will invest significant money to obtain them. This is also true to some degree when comparing good surround processors (either true processors or receivers like your 805 used as processors), although there are a
lot more variables involved and greater room for variation in performance (DSP, bass management, room correction, and D/A conversion) compared to amps because of that variation. I'll assume for the moment that you're just talking about retaining you 805 and adding a separate amp.
When comparing good separate amps to receiver amps, the equation changes a bit - in fact, some might say that it changes a lot, although it's worth recognizing that the magnitude of the differences depend on what receiver you're talking about. A separate power amp has several advantages. Larger power supply and better natural cooling both give a separate power amp the ability to produce more true power than a receiver. Take the Model 7700 and your Onkyo receiver as an example. The Model 7700 can actually output roughly 200W into each of its seven channels at the same time. Your receiver can output up to 130W per channel, but it can't drive all seven channels to that level at the same time. That 130W rating is for just two channels driven. The receiver's smaller power supply simply can't provide enough current to fully power up all seven amp channels to that level. Also, the Model 7700's 200W rating is at 0.03% distortion, while the 805's 130W rating is at 0.05% distortion. If we compared apples to apples, the 7700 could output more power while staying within 0.05%. Lower distortion and more headroom (available unused power) are just a couple ways that you can have better sound quality. In addition to sonic benefits, there is a much reduced potential for clipping at high volumes - and clipping is an
excellent way to kill a speaker.
In addition, the bigger power supply and heat sinks allow separate amps like the 7700 to drive lower impedance loads. Receivers are often not rated to drive speakers with an impedance lower than 6 ohms. Separate amps like the Model 7700 don't have that restriction, and can drive speakers with rated impedances of 4 ohms or even below. In the case of your receiver, the 805 is rated for 4 ohm loads, but Onkyo doesn't list what the output would be. The Model 7700 is rated at 300W into a 4 ohm load.
Finding specs on your Kappa 7's is tough, as they've been out of production for a long time. I couldn't tell what impedance they are, but I did see several comments that the Kappas (7, 8, and 9) were tough loads to drive. Speakers like that are more likely to benefit from separate amplification than speakers that are easy loads to drive.