Okay folks, I've had the A30/D30 combo for a couple of months now. I put in the Burson V5i Opamp upgrade. I highly recommend if you're looking for an improvement but not wanting to buy a new amp. I have a question I'm hoping someone can answer.
The A30 has a 3 position power switch; off, low, and "hi". I know from the owner's manual that it selects between low and high operating voltage. My question is when would it actually make sense to use one over the other. I've used this amp with HD58x Jubilees, HD6xx's, 32 ohm M&O's (32 ohm), some low impedance Betron IEM's. For the life of me, I can't tell a difference in sound quality or quantity between the 2 settings. The volume level doesn't change as it does when switching between gain stages. I'd like to understand why this option is even offered if it doesn't functionally seem to do anything. Thanks!