Connect Macs to analog amplifier?


I have 2 systems I need to maximize the sound quality from Itunes to stereo.
My main system is a Musical Fidelity A300 that connects to a G4 laptop. (Mission 735 speakers soon to be upgraded)

My secondary system is a Nakamichi receiver with Triangle Stella ES speakers
which connects to a new MacPro Tower.

Both the MF and the Nak have only RCA jacks and I need to find an affordable way to get the most out of my digital music. I was looking in the $100-$150
range and consider Blue Circle USB Thingee, Trends Audio UD-10.2, or M-Audio Audiophile USB. Im overwhelmed as there are so many ways to do this.
Suggestions much appreciated!
xistented
Hey xistented,

(Disclaimer: Non-uber audiophile comments follow)
I am likely a more-modest-audiophile. I related to your post due to mac and mission. My first foray into nice audio equipment were some tiny mission bookshelfs in college. I upgraded to the next model....this was mid 80's.

I am now a mac user (and have been for 15 years). G5 Dual and mac book pro. G5 is a server currently.

While I don't have hands on experience with the entry level USB converters, my first external DAC is a Monarchy NM24, which is a tube DAC. I have found that there is a clear difference between consumer level Receiver/Integrated Amp internal DACs to the external DACs. From my research I have found the common conclusion to be that to achieve a "noticeable difference" you need to be in the $1k range...which is very unfortunate! My *opinion* is that the entry level external dacs for $100-$400 will be different than the internal computer DAC BUT may or may not be to your personal sonic preference. in other words different folks like different things. You really have to experiment to find out which is to *your liking*. I am doing that myself with my first Non OverSampling(NOS) DAC. It is really all about the interrelationship between your audio components (speaker voicing, source, cabling, and room).

Apologies that I do not have a quick easy solution.

Good luck,
ed

Apple G5 Dual PPC AIFF server/Monarchy NM24 Tube DAC/ Anti-cable -VenHaus Cable /Tetra 120u bookshelfs + Martin Logan Abyss subwoofer /Technics SL1210 turntable.
The Trends audio unit would be a very good start if you already owned a Dac. An outboard Dac is the best way to go IMHO. Get as much of the conversion away from the Mac as you can. You will hear an improvement in sound. There are some inexpensive Dacs out there in your price range. I have no experience with them. Something like the Fubar II should do the trick.
Gmood1,

So the Trend Audio doesnt act as a DAC as well? I looked at the Fubar as a possibility as well, but it appears to act independently as well. What is the purpose of the two units?

Thanks, Im very green to all this stuff!
Does anybody have any experience with DAC707 Super Pro USB as an option in one box?
Yes the Trends can be used as a Dac. I wouldn't use it this way though. It is more geared for use as a USB converter.As far as I know the Fubar is just a USB Dac.