- Mar 18, 2007
- Reaction score
Most Fender BF amps used a tube rectifier, but not all of them. A rectifier does only one thing; it converts AC to DC. The "sag" characteristic that's usually associated with rect. tubes comes from voltage drop due to increased current demand. The amp loses it's capability to produce low notes; ie. spongy, no headroom. Solid state rectifiers were invented in the 50's, and they maintain a consistant voltage regardless of current. The amp has more power available to amplify the low notes; ie. headroom. Marshall started switching to solid state rectifiers in '67. Two of the most sought after tube amp brands in the world, Trainwreck & Dumble, use s.s. rectifiers....It was for this reason I went with a custom shop amp based on Fender BF topology.
FWIW, rectifiers aren't in the signal path, so in essense the actual tone of a s.s. rect. amp is still all-tube based. That is, unless the preamp is using diodes for generating distortion (Marshall Jubliee, etc.).