Arkless Electronics
Trade: Amp design and repairs.
I'm no expert, clearly, but that seems an awfully low impedance seen by a source component, not all of which would be comfortable driving. The input impedance of my preamp is a much more sensible 50kohm.
600R is a tougher load than 10kR, and will draw 16X more current for the same output voltage.
In general terms, output impedance of the driving component should be as low as possible, and the input impedance of the driven component should be as high as possible.
You wouldn't using full volume though for a start. 3k3 is an easy load for most SS sources and in fact the reason that op amps and certain other items are quoted into 600R is because at one time it was the standard impedance of all studio equipment and telephone relay equipment. Pro gear is still expected to work happily into this load. 775mV into this load is 1mW and = 0dBm which is why the figure of 775mV is sometimes seen as the input sensitivity of power amps.