fender no load pot

[nathan a]

Hey guys--

So remember fender's no load tone pot? Turn it all the way up and it clicks full-on ("off", more accurately), and the pot is removed from the circuit such that the path to ground no longer exists.

Would this be possible? --- To use it as a volume pot, and reverse the wiring such that when you turn it all the way DOWN, it clicks OFF (as in, zero volume; entire signal bled to ground)? Would this be any different than just turning a regular pot all the way down?

I've got a HSH setup, and would like to be able to remove the single coil from the circuit entirely. Each pup has independent volumes, and all three share one tone. Presently I'm just wiring the single's volume as a push/pull pot to switch on and off, but i though if I could use the no load pot, that would be cool.

Thanks guys

 

[DiMitriR33]

why three volumes? multiple volumes wired to work fully independant of each other load the pickup more when turned down. it's like turning a 500k into a 250k at maybe a 7 volume ( that's just a wild ass guess). this reduces the height of the resonant peak which gives a pickup it's charachter. normal pot wiring with multiple volumes will shunt the output to ground, if you roll off one the whole guitar gets quieter but the taper is slightly altered. good if you want to turn a p/u switch into an on/off switch or just have one loud position for solos and two not so loud positions. this wiring can also change p/u loading in a mixed position.

but to answer your question, no. i don't think you can get it to click in the down position though i've never seen one. it would take some work if it is posible. there may be a way to kill it in the up position and that would be good. if wired right you could take the load of the pickup and the pot out of the circuit(wiring a single with a humbucker can shunt out the humbucker and reduce output) and give some added volume. you can also try looking in places like digi-key for a switched pot that clicks when in the counter-clockwise position.

 

[Alfang]

The answer is YES, I am old enough to remeber when TV's had a volume/ on off knob.  we didnt have remotes, we were happy to get up and go change the channel.

 

[DiMitriR33]

sorry my tv had buttons.

i know they make em but can you find one in the right impedance?

 

[nathan a]

Hmm well Alfang you sound pretty certain, which is great. I might have to try this, then.

Dimitri-- I need 250k, which is what I believe all no-load pots carry. But, about your concern regarding multiple volumes affecting output, I'm wiring the volume pots like you would wire a jazz bass, not like you would wire a les paul, for example. So i THINK your concern does not apply? My understanding is that this way, each volume knob has no effect on the next because it never 'sees' the other volume pots in the circuit.

Anyone feel free to correct me, because I'm definitely still learning (aka, I messed up the wiring once already but that's alright, because I'm figuring things out and I won't make the same mistake twice)

 

[DiMitriR33]

i'm not sure how a jazz bass is wired but what i'm saying is that the impedance of the pot affects tone. lower values give less apparent highs. 250k pots are used on a single coil to mellow them out a bit. 500k is for hot pickups to allow more brightness. standard wiring for guitar has the #1 and #3 lugs on the pot connected from pickup hot to guitar ground. this always looks like one value to the pickup. the wiper (#2 lug) picks up the signal the pot and is connected to the output. the only way for the controls to work independantly is to hook the pickup across the #1 and #2 lugs and the output to #3 when you do this the pickup sees the rated value of the pot at full volume but as the volume is rolled off the value decreases. this will cause a loss of high end. if your set on three volumes i'm not trying to change your mind. i was making sure you were aware of this. also you may want to use 1meg or greater for all of your pots. even with one pickup at full and the others rolled off the pickup will see a resistance of 1/3 the pots rated value asuming they are the same. so 3 1meg pots will give 333k to the guitar. it would be a good idea to have some sort of switching in the guitar. if the pots are diferent values say 2 500k and a 250k like you might assume is the way to go the formula is 1/(1/a+1/b+1/c) so you get 1/(1/250,000+ 1/500,000+ 1/500,000) =  1/(.000004 + .000002 + .000002) = 125,000 or 125k ohms. and thats before you turn down any volumes.

i think if you use the 1meg pots all around you'll be ok. some yamahas have 300k pots and some people like 250k on a humbucker for a more mellow tone.

 

[allium_sativum]

Has-Sound.com carries CTS no load linear 250k, 500k and 1M pots.  I am not sure if anyone sells them in an audio taper and you will want an audio taper for a volume control.  CTS will sell you custom orders in a lots of 1000, so some small company like Has-Sound may have them. 

 

[-CB-]

Folks the answer is no.

The switch on the TV knob switched on the power to the main transformer.  The audio load was still on the volume pot.

If you try and do a no load pot for volume it will hum... because as soon as you lose your ground reference, either on the pickup or load side, thats what it does. 

There are three scenarios - one is to use a no load pot, and this will not do, as the volume pots are voltage dividers, with an input from the pickup, a reference to ground, and a variable output.  You can put the pickup's signal on the wiper, or on one end of the pot, but the other end of the pot in either case, must always be connected to ground, or it doesn't work.

Another  is to switch out the pickup when the volume is at zero, which makes no sense since you've got the pot effectively grounded out anyway at that point.

Another is to switch out the output, when the volume is at zero, and that may not work, because your floating (open) circuit will tend to want to hum. 

In effect, the load of the pickup is always there if its switched into the circuit.... just switch it out of the circuit and you'll do fine.  Use 500k pots, use 1m pots if you like.

 

[nathan a]

In effect, the load of the pickup is always there if its switched into the circuit.... just switch it out of the circuit and you'll do fine.  Use 500k pots, use 1m pots if you like.

Thanks CB, that makes a lot of sense. This is what I ended up doing, simply because even if the no-load pot deal is/was possible at all, I decided it would be harder than I'm looking for in a first wiring job. A switch to hop in and out of the circuit is working fine.