used DAC for under $350 Channel Isalnd....

I think Viggen is changing his set up. I wonder if he decided to keep the ScottDixon...His Gaincard and many of his power conditioning devices, as well as cables are up for sale.

Because of Viggen I've become interested in the Nixon TubeDac+.

I would say that the Scott Nixon Dac's are definately the way to go!

Correction: the assembled TubeDac from Scott Nixon is shipped to a buyer for $400, slightly above your requested limit of $350. And the assembled DacKit is shipped to the buyer for $250, leaving you with some extra cash to buy more CD's.

Here on Audiogon, Viggen already owns the DacKit, and I think he has compared it to another new design with a higher bargain price. Perhaps he will comment on his unit which falls easily under your $350 budget limit.

I'm not sure about the price, and you probably won't find a used one, but look into the Ack! DAC. It's getting rave reviews, and not too expensive.

For the newest ideas in minimalist, over-achieving DAC's in your price range, take a look at scott-nixon.com where the assembled and shipped package price is $250 for the basic DacKit. If your budget is a little higher, then there are a few companion DAC models, also. For the special quality of tube output, there is the TubeDac where the assembled and shipped package price is $350. For new models from an esteemed designer-manufacturer, this is about as cost effective as it ever gets.
The industrial design statement of these miniature DAC's is reminiscent of my Earmax headphone amp, another miniature over-achiever, which fails to share Scott's bargain pricing policy.