thevinoman -

The Mac pre and the 34I.5 should play well with each other. Looking at the specs, it doesn't look like anything would overload or 'underload' in normal operation with CD / DAC or phono. The 34I.5 has input sensitivity of 2.5V (for full power) so should give you noticeably more play with the preamp volume (and give you a lot more headroom) as compared to 1V sensitivity that many amps have.

The Mac has 15dB of available gain and you would need just less than 2dB of that to raise the 2V from a DAC to 2.5V for the amp. All that is assuming unbalanced RCA connection. (Balanced out of DAC is 2x V of unbalanced). If you have now or plan to get a DAC that operates in true balanced differential mode (containing a separate DAC module ea. for (+) and (-)  per channel) then you would need to use balanced XLR connection from DAC to preamp for it to operate in that way. Of  course it works with unbalanced RCA connection but the DAC is then using only one leg per channel.

As a starting point for setting things, turn the amp volume knobs back and forth before turning it on and find the halfway point. No fine precision needed. Turn all volume controls down, turn the preamp on, wait ~20 seconds, then switch on the amp. Another 40-60 seconds, turn the amp volume up to mid point, then raise the preamp volume to the sound level where you normally like it for that music.

As you get functionally comfortable with everything you can play around with adjusting amp and preamp volume controls vs. each other to obtain different sound characteristics.

So then, along with the power up routine, it should basically be plug and play for the Mac and the 34I.5

thevinoman- The Mac will play well with the Decware amp, promise you. It will take a little while to find the sweet spot with everything, plus the amps has to settle in. Don't over think it. Get the gear, hook it up, get some sound and play some music. Later, you can get OCD on the whole thing. Eventually you get to the point where ya fire it up and listen....Happy listening, keep us posted, Chris.

thevinoman- MC30's? I bought a pair of them from a customer in the late 80's when I was in the audio biz. Nothing compared to our Rachael but a great piece of audio history. Love to see a photo of them. Have a great three day weekend and happy listening, Chris.