I have an Electrocompaniet 4.5 pre-amplifier with 50k inputs. Balanced and Single ended. I use Balanced. The power amp is a Bel Canto REF500S. I used to use my Bel Canto Dac 2.7 to drive the power amp directly but found that it could sound a little too forward with a restricted soundstage. I put the Electrocompaniet between the DAC and Poweramp and had to make some adjustments with the output of the bel Cant 2.7 Dac as I was hardly getting any swing at all on the Electrocompaniet volume control. It was quite loud at 8 'o'clock. So if the "auxinput " comment is correct I may not be getting the best from my preamp. I read the Bel Canto manual that said the 4.5v Balanced output can be reduced to around 2 volts by reducing the fixed signal from 100% to 93.5%. I did this and now have good punchy volume levels @87db with the volume set at about 10'oclock on the rotary Electrocompaniet volume control. I think that control of the volume especially by remote control is better when a larger swing of the volume knob is possible. By the way, I can heartily recommend the Electrocompaniet Bel Cano partnership. They work very well together. Much improved over using the Bel Canto 2.7 DAC as a preamp and DAC.