Bias Board Maintenance
This upgrade replaces vital parts on the bias board. This improves stability and reliability of the entire amplifier. In Fender amps, this circuit regulates the negative bias voltage which dictates how the power tubes are operating.
In Fender amps with solid state rectifiers, this board not only regulates bias voltage but also regulates the main B+ voltage to the entire amplifier.
It is absolutely vital for everything on these boards to be working perfectly. We are starting to see original diodes fail in these 50-60+ year old amps. These kits help ensure bias voltage stability and reliability for decades to come. For amps with solid state rectifiers, this upgrade is absolutely vital for stability and reliability of the entire amplifier.
This kit assumes the amp is also being maintained with a proper Electrolytic Recap Kit, which replaces the bias cap on this board. In addition to replacing this cap (vital!) as part of our ERK, use this kit to bulletproof the rest of the bias/ss rec board.
Please be sure to select the proper kit for your amp, designated by tube or solid state rectifier, as both kits are very different! The entire solid state rectifier is upgraded in the SS REC kits with fresh new diodes!
Amps with solid state rectifiers include:
In a nutshell, all amps with 4 power tubes such as:
Twin Reverb
Showman/Dual Showman (reverb and non-reverb)
Quad Reverb
Super Six Reverb
Also these amps with two power tubes:
Bandmaster (non-reverb)
Bassman (all 50w variants, AA846, AA165, AB165, Bassman 50)
Amps with tube rectifiers include:
Super Reverb
Pro Reverb
Deluxe Reverb
Bandmaster Reverb
Tremolux
The Princeton (Reverb and non-reverb) has its own kit, please select accordingly
These kits are compatible with BOTH Blackface and Silverface models (unless you have a 135w or 70w Ultralinear amp).
These kits are NOT compatible with Brownface amps!! Brown kits coming soon!!
The SOLID STATE RECTIFIER kits are NOT compatible with the 135w and 70w ULTRALINEAR MODELS. UL kits coming soon!