Putting Hi-Fi gear in a mid-fi system -- HELP

Guys;

After many years I'm getting back into Hi-fi. Here's my joy and my problem;

I picked up a Theta DS Pro Progeny DAC for $175.00 (stealing it!) and I'm placing it in a (gulp)
Sony STR450 Mid-Fi A/V receiver, and the front end is an old JVC CD player swapping out with a JVC DVD player. First off let me say the sound from the Theta is obviously marvelous (with some limitations). First off the output voltage from the Theta on it's Ananlog RCA jacks is more than my Sony can handle -- on Extreme dynamic range peaks there is audible distortion.

At one time I thought you could buy small -2db or -4db attenuator pads you could place inline with your RCA jacks and cut down some of your juice -- does anybody out there know of such puppies ?

My second problem now is my CD player is not up to snuff -- no Toslink, and the digital co-ax jack distorts. Whwn I plug the Toslink in from my DVD player, 90 % of my distortion disappears. Can you guys point me to a good CD player/transport with fiber out that I could get at a good price ? I know you guys are gonna tell me I need to look at a good preamp with adjustable gain, but that's not in the cards right now -- still working on the WAF for more high-end gear and she likes the Sony for movies right now. So I'm looking for any help or tips you guys can provide.