Marshall DSL Bias Mod
Our Marshall DSL Bias Mod kit is designed to permanently fix overheating Marshall JCM2000 amps
Marshall JCM2000 amps when ageing tend to have the main printed circuit board start to become slightly conductive and bias to the EL34 output valves becomes unstable or goes very high and cannot be adjusted. This results in high valve anode current which cooks or wrecks the output valves.
This kit totally fixes this issue without the need for replacing the whole main circuit board. If you know how to use a soldering iron and know how to work on a circuit board then this is an easy upgrade.
The kit consists of a little printed circuit board with full instructions and picture on how to fit the board and saves on replacing the whole main board. Some expertise in soldering is needed to install this board. If you are not sure get an amp tech to fit the board. There are high voltages in these amps which can be lethal so please be extremely careful.
This version is designed for the DSL series. There is also a version for TSL amps.. The kits are assembled, stocked, and shipped from the UK.
We have used this kit in a Marshall amp ourselves and it completely solved the cooking output valves problem.
The product is supplied with the board, adhesive stand offs to mount the board, and full step by step illustrated instructions. We updated the instructions on July 2020.. This is not a Marshall product but is a solution that is fully proven through many folks following our instructions and successfully solving and overheating DSL amps.
Full instructions are included with your board. we can email a link to you on request so you can see how to install
There is special drill bit needed to drill the printed circuit board and this is included with the kit.
Click here to read a documented install by an amp engineer in Florida. It is good overview of his expereince installing the kit
Price includes is sent 1st class in the UK and is also available for shipment to Canada, USA Japan, Australia , New Zealand. We ship by Airmail to these countries. Please note that in some countries it is ok to receive goods but very challenging if you want to make a return.