Dana Music
- Site from luthier Dana Sutcliffe offers a guide to match Ampeg amps and speakers correctly, as well as downloadable Ampeg manuals.
- http://danamusic.com

Fuchs Audio Technology
- Design and hand-build tube amplifiers; includes model speficications and dealer network. Also offer a custom-build service.
- http://www.fuchsaudiotechnology.com/

Bass Gear Review Page
- Huge archive of bass-related user reviews including preamps, power amps, amp heads, speaker cabinets, combo amps, and effects.
- http://www.bgra.net

Compact Bass Guitar Speaker Bottom
- Len Moskowitz' famous compact bass cab plans. Gonzo sound for the do-it-yourselfer.
- http://www.core-sound.com/bottom-article.html

ESP Projects
- Audio projects including amps and preamps suitable for musical instruments amps, effects, and some neat subwoofer/processor plans for bassists.
- http://www.sound.au.com/projects.htm

Harmony Central Amp Database
- Large database of guitar and bass amplifier and speaker user reviews.
- http://www.harmony-central.com/Guitar/Data/

Acme Sound Bass Speaker Cabinets
- Andy Lewis' flat-response extended-range "Low B" line of 3-way bass speakers. Direct sales.
- http://www.acmebass.com/

valveamps.com
- Collector and restorer of old valve guitar amplifiers describes his collection.
- http://www.valveamps.com