Fender Blues Junior Mods
The Fender Blues Junior is one of the most popular guitar amps ever made. It has been around for over twenty years and has had numerous upgrades in that time. But despite all of this, the Blues Junior has not been without its problems. The Blues Juniors that have been exported to the UK seem to have the most problems and this is because of the EU rules on mains voltage settings on electrical appliances in general coming into the UK. When all Fender amps arrive in the UK the mains power voltage is set at 230 Volts. The UK mains power voltage fluctuates between 230 and 240 Volts and sometimes a good bit higher than that. I often see the voltage rise to 242 where I live. People have left comments on my You-tube channel saying that they see as much as 248 Volts where they live. So why does this cause problems? And what can be done about it? The first problem is that it pushes the heater voltages on the tubes above there working voltage which is 6,3 Volts. More than a 10% rise will shorten the lives of the tubes. At 240 Volts you will see around 6.9 Volts or more. Another more serious problem is the rising HT voltage caused by the extra 10 or 12 Volts for the mains power feed. This rise will cause and extra 10 to 15 Volts on the HT voltage. This combined with the fact that Fender biased these tubes at 100% instead of 70% is a recipe for disaster. So, what can be done about this problem? Despite these amps coming into the UK set at 230 Volts. There is a 240 Volt setting for these amps. Watch the videos to find out how to change you Fender Blues Junior over to 240 Volts.
The videos also cover how to bias your output tubes to 70% from he perilous 100% set at the factory. There is also lots of mods and info to help improve these easy to transport guitar combos and get them sounding more a Fender amplifier should sound.
Check out the video below of the Keld Ampworks Bias Mod Kit This is a fantastic mod for the Fender Blues Junior, up to the model 3. If you have a Blues Junior 4 then you do not require this mod. This mod is only for the fixed bias versions. Remember the Blues Junior 4 is cathode biased. There is a video on how to fit this mod.
I have now added a video on The Fender Blues Junior 4. This is the latest version and there has been some major changes. If you have bought a brand spanking new Fender Blues Junior in the last 5 years, then it is probably a version 4. The version is cathode biased and not fix bias. This is the biggest change made to the version 4.
You can also watch the full playlist on my You-tube channel. It contains all the Blues Junior guitar amplifiers that I have worked on
Fender Blues Junior Part 1 Full Recap and Mods
Fender Blues Junior Part 2 Full Recap and Mods
Fender Blues Junior Bias Mod Kit by Keld Ampworks How to Fit and Bias
Fender Blues Junior Model 4
Fender Blues Junior Schematics
Fender Blues Junior Schematic, Green Board