need help selecting the right preamp

I have a pair of Polk LSI25 floor speakers, and a center channel LSI C. The room doubles as a TV/theatre room as well, hence the center speaker. Most of my music is mp3 format 320 bitrate, so I'm not sure if a high end DAC would add to the fidelity. I'm essentially using my pre/pro built in DAC with my current setup, since my connection is now fiberoptic from imac to pre/pro? Tube units maybe a little too fragile for my setting, because I have 3 little kids that like to sneak into the room, and a housekeeper that likes to bang the vacuum cleaner against the rack.

I would agree with the above, get an DAC for between your computer and Pre-amp.

My question is why three channels? Which three channels are you running?

I see you have a three channel amp but what speakes are you using?

With out knowing exactly what your goal and budget is, I would buy a good DAC, even maybe something like the Marantz music Network player, or pioneers has something similar. And then run that in to a good tube Pre-amp, find a good used Audio Reseach LS-16 or if you have the money there are quit a few good Pre-amps out there.

Then I would hook I up via 2 channel and do you best to setup the speakers correctly and you should have a great sounding system. But remember, I am not there and I don't know what your exact desires are when it comes to the end result so no guarantees are given.

I hope this helps a little.

Thanks for your input. I found a good solution after speaking with Apple tech support. The headphone jack line out from the imac actually doubles as a fiberoptic output. Toslink makes an optical cable with an adapter to make it fit into that headphone jack. I was able to hook up the other end directly into the optical input on the preamp. Good music :)

The above post is good. Another alternative is to get a good USB to SPDIF converter (Audiophilleo 2 is good) and a DAC with S/PDIF in. Some knowledgeable people claim the clock in the USB/SPDIF converter has more impact on sound than the DAC itself, but you will still need a DAC.

Yet another alternative is getting a DAC with asynchronous USB input, and go from iMac to DAC without the above-mentioned converter. Some examples: wavelength, Wyred4Sound, Ayre, Empirical Audio.

Using the headphone jack output on an iMac into the analog inputs of a preamp isn't going to sound very good, as you've discovered. Doing that means you're getting a signal that has already passed through the low-quality digital to analog converter and amplifier inside the iMac.

The simplest way to improve the quality is to get a decent digital to analog converter (DAC) with an optical/Toslink input. Connect that input to the iMac headphone jack with an optical cable with a Toslink connector at the DAC end and a mini-Toslink connector at the iMac end. Then connect the analog outputs of the DAC to one of the analog inputs of your Outlaw preamp.