Confirm This Circuit

ericw · #1 03-15-2010, 09:00 AM

P-bass with tone control, no vol. Is my schematic correct? I had read in another thread that you may want to use a resistor to mimic the vol pot on full - where should I put that? Or should the value for my tone pot change - accomplishing the same thing?

tofe · #2 03-15-2010, 09:06 AM

I think the schematic is correct !
When the vol pot is full, the resistance is 0 ohms, so IMHO you don't need any resistor.
It's funny because yesterday I was thinking about something like that, as I don't use the volume very often.
In fact I had the idea to replace the volume pot by a switch, so I can have full volume, or only 80% depending on the resistor value.

**line6man** · #3 03-15-2010, 09:12 AM

Quote:

Originally Posted by tofe

When the vol pot is full, the resistance is 0 ohms, so IMHO you don't need any resistor.

0 ohms from pickup to output, but the full value of the pot (250K or 500K) to ground...

I wouldn't worry about the resistor, since you have a tone control.
If things get too bright, roll down the tone to even it out...

The diagram is correct btw.
This seems like a very odd setup to want a tone control, but not a volume. Have you considered a killswitch?

ericw · #4 03-15-2010, 09:26 AM

Quote:

Originally Posted by line6man

This seems like a very odd setup to want a tone control, but not a volume. Have you considered a killswitch?

Well, the setup is based on what I use. For some reason I strongly dislike having controls present that don't get touched. Onboard volume control is always set to 'full' for me, but I adjust the tone control somewhat frequently. If I were to try and dislike it I could change it back easily enough.

The killswitch could be handy. Would that just be a SPDT in between the pickup and the tone pot/grounding point?

megadan · #5 03-15-2010, 09:30 AM

Quote:

Originally Posted by ericw

The killswitch could be handy. Would that just be a SPDT in between the pickup and the tone pot/grounding point?

Yup, just make sure to switch the input off to ground and not just to nothing or it will probably pop or buzz.

ericw · #6 03-15-2010, 09:36 AM

Updated diagram with spst killswitch added.

**line6man** · #7 03-15-2010, 09:40 AM

A simple SPST switch from the tip terminal of the jack to the nearest ground point is all that is needed to do a killswitch.

As megadan was saying, you want to ground the signal rather than interupt it.

If you just leave the output open, you will end up with that "open guitar cable" buzz, and there will likely be more switch pop noises.

ericw · #8 03-15-2010, 09:45 AM

Makes sense. Thanks all!