I know that other BCers were recommending that you get the 8 ohm version of the std104hf so you could add another 8 ohm cab if you wanted more volume, but as you only want to use one cab you may have been better served by the 4 ohm version which allows the LM3 to output its 500 watts not the approx 300 you are currently getting. The difference may be marginal but when I run my LM3 into the 4 ohm std104hf with both gain and master at 12 o'clock the volume is staggering. Both lm3 and LM800 have digital power amps these days. Maybe the previous analogue power amp LM3 was more powerful?