I assume the 990 is a trade-in or a used model, since Outlaw is an internet direct retailer not sold in stores.
I faced a similar choice between the Sherwood-Newcastle P-965 (same platform as the Outlaw) and the Yamaha 1500 & 2500 and Denon 3805 receivers 2 years ago. One of the tests I do with a preamp or receiver is to turn the volume all the way to maximum with no source playing, and then listen to what comes out of the speakers. When I did that with the Yamaha, the hiss coming out of the speakers was much louder than with the Denon or the Sherwood. I did not do additional testing to determine if the hiss was coming from the preamp section or the amp section of the Yamaha. I bought the Sherwood and have been fairly happy with it, except for a few occasional quirks.
With your Yamaha used as a preamp into the 7 ch amp, do you get noticeable hiss from the speakers with no source playing? If you do, then the Outlaw would probably be a big improvement. If you don't, then the hiss that I heard from the Yamaha is probably coming from the amplifier section, which you are bypassing, and so the Outlaw would only be a small to moderate improvement. Any improvement would be more noticeable with music than with movies.
P.S. -- If I was in the market for a pre-pro right now, I would want HDMI 1.3, which the Outlaw does not have.
P.P.S. -- Outlaw's website has active forum discussions where people have compared exactly the two models you are asking about.
I faced a similar choice between the Sherwood-Newcastle P-965 (same platform as the Outlaw) and the Yamaha 1500 & 2500 and Denon 3805 receivers 2 years ago. One of the tests I do with a preamp or receiver is to turn the volume all the way to maximum with no source playing, and then listen to what comes out of the speakers. When I did that with the Yamaha, the hiss coming out of the speakers was much louder than with the Denon or the Sherwood. I did not do additional testing to determine if the hiss was coming from the preamp section or the amp section of the Yamaha. I bought the Sherwood and have been fairly happy with it, except for a few occasional quirks.
With your Yamaha used as a preamp into the 7 ch amp, do you get noticeable hiss from the speakers with no source playing? If you do, then the Outlaw would probably be a big improvement. If you don't, then the hiss that I heard from the Yamaha is probably coming from the amplifier section, which you are bypassing, and so the Outlaw would only be a small to moderate improvement. Any improvement would be more noticeable with music than with movies.
P.S. -- If I was in the market for a pre-pro right now, I would want HDMI 1.3, which the Outlaw does not have.
P.P.S. -- Outlaw's website has active forum discussions where people have compared exactly the two models you are asking about.