Purpose of Switch in EMG-HZ Passive Diagrams

Looks like Gibson Les Paul style wiring to me. Two volumes and a switch. Not necessary, but another option.

 

it looks like, but i am no expert in electronics

 

The BTS always sounds better running on 18V. I haven't used it witht he passive pickups, but it sounds better that way with the actives. You get more headroom which equals more punch.

 

My opinion was based on actually using EMG pickups and BTC systems in 4 different basses that I built for the last 10 years. Originally I ran the systems on 9 volts.

Later I switched them to 18 V and you could hear more punch. On 9 Volts they are more compressed sounding. Since that time EMG started recommending 18 volt operation for all their bass systems.

Don't forget that these devices use op amps, which are not made to run on a single power rail. So after you split the 9 volts in half, you are running on +/- 4.5 Volts.

On the other hand I make JFET preamps that run on 9 volts and they are fine, because that's how they are designed. Running them on higher voltages doesn't give you more of anything, except noise.

It has nothing to do with "hitting the head". You wont get more output level on 18 volts, you will will get wider voltage swings, because there's more available to the op amps.

This is from the EMG instruction sheet:

 

This thread is about EMG-HZ pickups, which are passive. and the OP has not mentioned any EQ circuit.

 

Go to post #5:

So I pointed out that if he was using the BTS on 9 volts, that would be true. Run the BTS on 18 volts and you wont notice a difference.

It wasn't for this particular setup, but he did mention a preamp.

 

Only if you have your volume controls miswired. The switch is to switch pickups as on a Les Paul. Not too many basses are set up that way.

Every two volume control bass in the world completely muts the volume when the volume controls are on zero.