Triode mode vs pento mode

Triode mode offers lesser power at an alledgedly better sound quality than Pentode. Hopefully Al will stop in to explain it better. Al...... :)

better bass w pentode, possibly with some hardness; lower power but more spacious sound with triode. with my amp, the larger scale works (e.g. symphonies) and rock usually sound better with some pentode dialed in; chamber music or small acoustic groups, triode sounds better.

Triodes are some of the most linear amplification known to man. Pentodes are not and generally need negative feedback correct to be useful for audio.

Good bass has nothing to do with the amp being triode of pentode; good bass results from having the correct relationship to the speaker (see: http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php and proper bandwidth to play bass in the first place. That is not an issue between tube types.

Atmasphere, there might be some issue since triodes have lower internal anode resistance leading to higher damping factor and perhaps perception of less bass.

Pentodes are less sensitive to supply voltage variations meaning that large change in supply voltage cause very small change in plate current. Triodes require better power supplies. I also read somewhere that pentodes are noisier.