@daveinpa "...But I couldn’t tell the difference between my 200 dollar topping DAC and simply plugging my laptop audio out to preamp rca inputs..."
I do not think Topping $200 ish or even sub $200 Dac (assuming your Topping Dac is one of the good ones in ASR) is that bad (unless the internal Dac inside your laptop is equally good). First off, the average output voltage from a laptop jack output is around 1.5 volts, slightly lower than the 2 volts of Dac output and the P.A input. So I believe, with everything else being equal, the volume output level will have to be lower from laptop->PA setting. Secondly, even you match the volume level with ext. Dac->PA setting, the internal Dac of laptop is in general less quality (Mac uses Cirrus Logic and is generally better) that results in less dynamic, less bass, less full midrange, and less almost everything as compared to entry level Topping or other well-received brand such as Smsl. When I upgrade from the entry level Dac to mid-tier (around $500), the improvement is also pronounced just like from laptop internal Dac to entry level external Dac. I think this "accerlerated return" improvement is consistent with what is shown in the ASR’s measurements.