I note, btw, that the ARC Ref 150 has a specified 3 db bandwidth of 120 kHz (at 1 watt, with an 80 kHz "power bandwidth" also being specified), and JA's measurements indicate a bandwidth of approximately 100 kHz (for an 8 ohm load connected to the 8 ohm tap), with excellent reproduction of a 10 kHz square wave (under small signal conditions, as noted under the graph).
Hi Almarg, thanks for the feedback.
I did also note the very same specs as you wrote above & also noted that these were mostly under small-signal conditions while slew-rate is a large-signal parameter (as you already noted in an earlier post). When the amp is outputting a lot more power then i believe that the distortion will be much higher & the various BWs cited in JA's measurements will constrict & that 10KHz sq wave won't look so pretty anymore . That's why a 66KHz BW at max rated power under the stated 13V/us slew rate did not seem unreasonable to me. The effect of the excess phase shift would thus be more discernible (vs. lower power outputs).
