Fender Blues Junior Bias Mod Kit
£15.00 – £79.00
Description
This is a Fender Blues Junior Bias Mod Kit. This kit is available as a single assembled PCB or in multi packs of bare PCBs.
Fender Blues Junior amps have one major design flaw. They use a non adjustable grid bias in the power stage, and it’s set far too high. I’ve seen as high as 130% idle bias on units straight out of the factory. It’s no wonder so many of them set themselves on fire!
I used to modify every blues junior for a variable bias by popping the board out, neatly drilling the PCB and fitting a trimpot. Then I realised that it’s possible to add a Bias mod PCB that allows you to change the bias without removing the Blues Junior PCB. So I designed one.
This Blues Junior Bias mod kit is designed so that in the unlikely event of the pot wiper going open circuit, the power valves grids swing negative, saving the valves. Much of the advice on the internet about doing this mod misses this – those mods will leave the grid floating up towards GND in the event of pot oxidation, which will destroy the power valves.
Here’s a video showing the easiest way to do a Fender Blues Junior Bias Mod:
Additional information
Pack Size | 1pc, 5pcs, 10pcs, 20pcs |
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Assembly | Assembled, Unassembled Kit, PCB Only |
Paul (verified owner) –
Excellent product and customer support. The bias board works as described and RSD Sound’s customer support has been top notch helping with my questions during the installation.
Gregory Lynch (verified owner) –
Quality product. Easy install. Worked as described to adjust the bias. Quick shipping to the USA.
Julian Balle (verified owner) –
The kit arrived in Australia within a week of placing my order . Was an easy install and this is coming from a person who’d never opened the back of an amp until a few weeks ago. Just follow safety precautions and you’ll no problems doing this mod yourself . Happy camper !!