By Ed Malaker
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My son built a Strat and included two input jacks.
His desire is to plug one amp into one input and another amp into the other.
The problem is that he wants to use a form of balance knob so that in the center position it sends equal volume to both amps. Then, as you turn the knob in either direction, it increases the volume to one amp while equally decreasing the volume to the other, in a smooth blend as you turn the knob.
He has available space for the knob on the pickguard, as he removed a tone knob and rewired it to have a master tone control.
What type of knob should we use and how do we wire it all in?
Hello! Great question, and congratulations on building a Strat, especially one that’s unique, with two stereo outputs. I’d need to see a diagram of the wiring to do any troubleshooting, but I think I can answer your question without it.
On the one hand, the solution is easy because you only need to install a potentiometer and maybe some resistors. On the other hand, you’re dealing with two different amplifiers that will have different impedances (loads), and it will be hard to set them both at the exact same volume, so circuit performance can be hard to “tune.” Let me explain.
In Example 1, We illustrate the easiest way to add a balance control to the circuit.
I recommend starting with whatever potentiometer you have on hand. Since it is a Strat, you probably have a 250k pot, which is perfect. You can use the tone control you removed.
If the balance doesn’t work the way you want it to because the center is not the center, the volume doesn’t turn all the way off when you switch to one amp or the other, or it shuts off too quickly when there is still dial to turn, you will need to adjust the value of the pot. We recommend moving to a 500k pot next, then a 1000k pot, often called a 1MEG pot. One of these three values should give you the performance you need and be more than adequate for most tasks.
If you are a glutton for punishment, you can fine-tune the circuit further by adding a resistor in front of the pot, as illustrated in Example 2.
We recommend starting with a 30k resistor and moving up until you find the value you need. It can get tedious, but you should have an idea of the correct value if you tried all three pot values.
If you can make room in the pickguard, you can also use a second volume, as illustrated in Example 3.
We hope this has answered your question, and that it helps you get your guitar working the way you want it to. If you have any other questions, or this solution doesn’t work as you need it to, please let us know and we’ll help you get to the bottom of it. If you have learned something new, please feel free to share this guide on Facebook and Twitter. For more articles on guitar electronics, visit humbuckersoup.com.