I second Hungryear and Bamafan, the Aesthetix IO is the best I've heard of this breed. More than enough gain to drive an amp without a line stage. When you see the volume control you'll know why it costs an extra $2500! And if you want to go all-out, you can do what Albert Porter does and get a separate power supply for each channel--just be prepared for a lot of heat and weight, as this is an all-tube unit, including the power supply, with well over 20 tubes in the standard, one power supply version.