Just got Sundaras and love them. Currently driving with Apt/Holman pre-amp fed by Bluesound Node. Sounds good but pushing the preamp (higher volume on the dial) and wondering if there is an upgrade possible by using a dedicated headphone amp for around $500? Also have a Topping D50S - so in theory could bypass Node DAC into the D50S then into an amp, or bypassing the Node DAC into a combo DAC/Headphone amp like the IFI Zen Dac V2 for instance... Love the streaming ability of the Node and not looking to remove that from the equation, but open to suggestions. Thanks!