I am fairly new to electrics and only have owned a basic starter amp. I upgraded and purchased a TA-15 for home use and love the flexibility and sound on 5w mode. The issue is the 15/25w modes have a loud hum, not a hiss as others have reported. I understand tube amps may have some but the level is beyond what I would think is acceptable for an amp geared toward home and studio use. If you listen to this demo http://www.youtube.com/watch?v=0jD9zCvyVgg you can hear the same hum my amp produces. Listen closely right when the video starts and when he changes the channels on the amp and you will hear exactly what my amp is producing. Is this amount of hum normal for tube amps? I've done all the troubleshooting suggestions in the manual and everything checks out fine, tried different rooms and even a power "cleaner" with no improvement. Although the demo obviously has a guitar hooked up, mine makes the same noise with and without an instrument connected and the volume, gain and tone control settings have little impact, just a tad louder if the volume/gain is turned up. Thanks for any input.