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previous: David B. This question is about a solid-sta... -- 2/5/1998 5:34 PM View Thread

Re: channel switching

2/9/1998 11:41 AM
ethRe: channel switching
Well what you may want to do is come up with an equivelent electronic switch of what I am assuming is now mechanical.  
 
I like to use J-fet's as switches. Kevin Occonner's Ult.Tone 1 is a great source for switching.  
 
For two pre's- drill a new hole for second volume. Replace pot with 2 pot's of 2x original value( this will keep the load resistance the same). Wire them like parallel volume control's, the wiper taps go to your switching elements (only one switch element open at a time). The elements will 'choose' which volume the signal moves on to the next stage from. Control will be described later.  
 
Post- You really only need this for the distortion channel, so interrupt its ground with a switch that will close when distortion channel is selected. And open, full vol, with the clean channel.  
 
Control- For j-fets you need a negative supply.  
It may be alot easier to use a 4066 bilateral switch( no need for neg. voltage) but use anything you like. You'll need one inverter circuit from the footswitch, and plug in an RC time constant on the output to switches to eliminate pops. One more thing put diodes into the gates of the j-fets. Diodes are needed so that the signal voltage (on vol. select) does not screw with the j-fets bias. (because bias voltage is the diff between gate voltage and source voltage)  
 
I hope this is understandable, I am not as descriptive or clear as alot of writers, but this is how I will learn. So thanks, and I hope it helps!-eth