Bass Oddity- Tone control does next to nothing

[Rip Topaz]

I just picked up yet another P-bass, and this one is a heavyweight (just over 11 pounds).

When I first got it, it had an active EMG pickup set. I noticed that the tone control didn't really do much. By comparison, my other main player is a nice 9 pounds and the tone control goes from bright to "blanket on the amp" mud.

Here's the thing. I swapped the pickups for a passive GZR set (which sounds great), and still the tone control doesn't really do much at all to the tone.

Is it possible that the density of the body is causing this phenomenon?

Anyone else have a really heavy bass which has a tone control that just doesn't seem to do anything?

Btw, everything is hooked up correctly. Already double and triple checked that.

What say you?

 

[elgecko]

I don't believe the EMG pots are the right value for passive pickups.

 

[Bobster]

EMG makes two types of tone pot, a 25K ohm (black pc board) for active and 500k ohm (green pc board) for passive pickups. Here's a link to the datasheet: Invalid Link Removed

All the best,

Bob

 

[Steve Dallman]

Standard basses use 250k or 500k pots for volume and tone. Active use values one tenth of that...25k-50k. The caps go the other way. Passive use .022uF or .047uF typically. With active multiply by 10, so .22uF-.47uF.

Active pickups with passive value volume and tone will not work well. The volume will likely have all the control on one end, and the tone will be very ineffective.

Passive pickps with active values will be very dull and the tone control will be quick mud.

 

[Rip Topaz]

So if I swap out the current (500k) tone pot to a 250k, do you think that'll give the tone control more range?

Btw, it never gets close to mud.

 

[Bobster]

Rip,

A GZR P should have a 250K pots. Here are the wiring instructions for that pickup: Invalid Link Removed

 

[ggunn]

Check the easy stuff first. On passive instruments there is a capacitor that makes the tone pot work. Check and see if one of the capacitor leads has come unsoldered. If that's not the problem and if work has been done on the electronics, look up the wiring on line and make sure the capacitor wiring (and the rest of the wiring) is correct. If the cap has come unsoldered or if it is attached to the wrong terminal(s) of the pot, then the bass will act like how you are describing.

 

[Rip Topaz]

Thanks everyone. I'll pop it open and give another look. Could've sworn I saw a 500k value on the pots.

 

[M.R. Ogle]

As others have stated, it's likely a mismatch of component values.

 

[Jeff Scott]

Everyone loves to talk about pot(s). What is the value of the capacitor in the tone circuit of that bass.

 

[Bobster]

These are EMGs they use proprietary wiring and pots. They don't use a cap if you wire them per the instructions.

 

[Jeff Scott]

These are EMGs they use proprietary wiring and pots. They don't use a cap if you wire them per the instructions.

How do they get away with no cap in a tone circuit. Must be pretty special, eh?

 

[Bobster]

Jeff, All EMG pickups are designed to work as part of a system. Here are the install instructions for the Geezer Butler P Pickup: Invalid Link Removed

Bob

 

[Jeff Scott]

Jeff, All EMG pickups are designed to work as part of a system. Here are the install instructions for the Geezer Butler P Pickup: Invalid Link Removed

Bob

I bet there's a capacitor somewhere on the circuit board the tone pot is mounted on.

Potentiometers by themselves do not make a tone control.

 

[ReidK]

I bet there's a capacitor somewhere on the circuit board the tone pot is mounted on.

Of course there is. It's a surface-mount cap right next to one of the pot legs:



Rip, the first step is to determine what you have. A 500K pot will work just fine, but you do need a capacitor to make it a tone control.

And the weight of the bass doesn't matter.

Reid

 

[Rip Topaz]

There is a capacitor mounted to the tone pot. EMG uses its own system, everything is plug-and-play. The pots are 250k.

I'm wondering if I didn't knock something loose when I crammed it all into the control cavity. I'll tear it open again tomorrow.

Thanks for all the help so far, guys.

 

[Jeff Scott]

I just knew there had to be a capacitor somewhere!

I hate those SMT buggers, no values written on them. I put those on PCBs all the time. By hand. Under a microscope. With tweezers. Mostly 0603s. A few I populate the boards with are large enough to have some writing on them.

 

[rolandm]

I know that when my orange drop in my Fender Jazz gets too close to the grounds, it'll go completely treble. That's how I know a wire inside has shifted somehow.
Which reminds me. I need to locate my small zip ties.

 

[rolandm]

That being said, maybe a Tonestyler is an appropriate choice.

 

[ZorgRift]

this bass oddity could be a grounding issue.

... perhaps a problem of ground, controls to major tone

(i'll see myself out, tip your bartender)