Is there an audible difference using peripherals

Agree with Plato, and also with Russ about the relevence of quoting the very meaningless manufacturer's distortion specs. Do what sounds best to you, but if it doesn't help the sound appreciably, you're technically probably better off without it. However, if more dynamic and accurate overall sound is what you're after, and especially if you find you need to keep the EQ in-circuit most of the time to get enjoyable sound, you should probably consider beginning at the beginning to undertake a comprehensive upgrading process that will eventually render all the outboard 'help' obsolete.

i couldn't agree more with the above. I used an eq for a while when I was limited to small Mission speakers. It gave me the freqs I wanted. But in the slightest way, it made the (fumbling for words) *saturation seem less. At worst it was as if I went from CD to tuner, at best alot less dramatically, still doing the same *watering down.
There are better, but this was with a $700 Yahama eq. As the others have illuded, and was true in mine, something is missing in the electronics if that much other is needed. In my case, it was the speakers, and those tapes later had me employing the eq on a much better system. But sometimes you just can't make it sound better.

Thanks guys, and since my Soundcraftsman has been misbehaving lately, the Parametric on my Preamp can fine-tune what I lack.

I eventually want to go down the "tube" route.