Unless the integrated has a passive preamp section, incoming voltage, 2V,3V, etc, shouldn't be a factor since the preamp section usually would be active. You should note, however, the input impedance of the integrated. Incoming and outgoing impedance is important for EVERY component, regardless if it's cdp to preamp, dac to preamp, or preamp to amp. The general rule of thumb is that the output impedance of a component should be ten times LESS than the input impedance of the component it's going into. For example: if the output impedance of a cd player or dac (whichever your system has), is 5,000 ohms, the input impedance of the integrated amp should be 50,000 ohms or greater. 5,000 ohms is very high but they do exist. The industry standard for an amp's input impedance is 47,000 ohms.