Pretty nice if you replace the stock tube

I needed more gain for some dynamic mics (the wimpy preamps in my Alesis io14 were clean, but weak) and this one filled the bill. However. The first 30 minutes after powerup it sounded like popcorn. It settled down after that and performed pretty well, with occasional bursts of noise. After being on a few hours, it developed background noise like a jet airplane at takeoff. So I bought some replacement tubes from a tube specialist on eBay (The Tube Store)--some GEs made in the '60's, very low noise, high gain. He diagnosed the stock tube as "gassy", taught me some interesting stuff about tubes. Spent way more time than I expected on this transaction.The replacement tubes make the ART unit sound great--absolutely no tube noise at full gain, and it runs all day without changing. The replacement tube cost about $30, about half the original price of the unit, but worth it.Since I bought two tubes (for $60), I am going to get another ART TubeMP, pop the GE tube in, and get going with my two channel voice work.