b17krk wrote:Thank you Paul, I really appreciate you taking the time to help out. You are a true gent!
OK Kirk, here’s what I did. I modified the L-2000 Plus circuit so as to not add any extra holes to the bass. What you will be doing is replacing the current pickup coil configuration switch (4PDT) with a DPDT on/on/on switch. That’s the switch above the Treble control. Next, you will be replacing the volume control (250KA) with a 250KA pot that has a DPDT pull switch attached to it.
Basically you will be re-wiring the passive/preamp control switch to be the bridge pickup coil configuration switch. The preamp control option will now move to the pull switch on the volume control, more on that later. Hopefully this wiring diagram will be clear enough to do the entire mod without any issues. If you run across any problems, let me know. Anyway, here it is.
As you look through this diagram you’ll see an asterisk by the Red wire from the preamp and a connection I labeled “A” off the pull switch on the Volume control. I wanted to add some notes to the drawing but it just took too much room so I’ll put the notes here in the document.
Notes: The pull switch on the Volume control has 2 positions. The bass is operating in passive mode when the Volume control knob is pushed down. To go into Preamp mode, you simply pull up on the volume knob. In preamp mode, the preamp is not in the Treble Boost mode unless the Red wire from the circuit board is connected to “A”. If you tie the Red wire off and leave it isolated, the bass is only in the Preamp On mode. If you wanted to have the preamp on with Treble Boost, you would simply connect the Red wire from the preamp board to the switch connection labeled “A”. Now, if you wanted to have a little Treble Boosting when you activated the preamp, you would connect the Red wire to the “A” connection through a resistor. In other words, you would solder the Red wire to one leg of a resistor and tie the other leg of the resistor to connection “A”. The larger the value of resistor, the less Treble Boost you will have. A resistor value of around 1K would give you a pretty good boost while a value of 100K would be pretty mild. Experiment around and see what resistance value you like.
So, there you have it. An L-2000 Plus without drilling a hole in your bass. Keep us all up to date on your adventure with the mod. And again, thanks for being willing to explore.
Paul