External DAC for Sony SCD-777ES

I don't think you'll find a great dac in that price range or at least one that will overthrow your modded Sony. I used to have an Audio Note 2.1x balanced dac that was better than the redbook section of my xa9000es but that was more than your budget allows.

I agree with Chuck and think that vinyl where may be your best investment...

Happy holidays

you might be able to get some improvement with a power conditioner - my experience has been that CDPs benefit most from it.

otherwise, I'd audition at length before buying an external DAC; the modded Sony is already up there with the best digital (I have a Kern-modded SCD-1)

Your thread doesn't mention if your player has the super clock installed. If it doesn't then this is where you need to put your money. The super clock upgrade is a huge improvement over the stock clocking circuit.

I do not have the Superclock. I believe it is two parts. A circuit board and a power supply for the circuit board. Is this a mod I can do myself or do i have to send it in? Does this upgrade only change redbook or also improve SACD?

You've done quite a bit of trading here so why not try some of the popular dacs in your price range and see what you like. As you prefer used you know you can do this with little $ worry. There are numerous options in your price range but if I were to make a specific recommendation I'd say try a used Bel Canto dac2. Very ice for the used price.