I've had my SLB for about 6 months, and yes, LOTS of hiss when the SRT is on (always, in my case--which is why I bought it). I'm very disappointed for the price, and considering Yamaha makes tons of really high-end, pro audio, you'd think the preamp wouldn't be this noisy. I'm going to see if the dealer can do anything, as others here have said theirs are quiet. On another note, I've been looking at the bass array speakers. I play mainly with big bands. Do you have the 10 or the 12? Is it loud enough?
Mattgreven I believe both the amp and extension speaker are 10" Woofer with 4 x 2.5” Cone-driver Line Array. I have the amp and extension speaker so can access the full 300watts and that is plenty loud. With only the amp it may not be as loud but that is dependent on how loud the band is and what sound reinforcement is available. With EUB you can push the volume much louder than double bass without feedback so the amp by itself may work.
And still getting the hiss through the SLB300. I have to roll all the treble off to eliminate the hiss.
