Shown here next to a standard 5881 tube

The 6AK6 tube

The tiny 6ak6 tube is a 7-pin miniature power pentode that is capable of dissipating 2.75 watts each. All amp models are available using a pair of these as output tubes for an amp that delivers around 4 watts of power. 4 watts is plenty of volume to keep up with a full live drum kit or live playing in a smaller venue without a PA system. Through a 4x12 with efficient speakers it can get quite loud. I've been using these tubes for years and haven't had one fail yet. I have a small stock of NOS JAN and RCA tubes that seem to be indestructible.  As a side note -they are also dirt cheap and easy to find since they were used in a variety of amplifiers and car radios back in the day. A pair of these really delivers that pentode punch just like a full power amplifier would but at much more manageable volume levels.