2 vol, 2 tone control question

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burndog

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This should be an easy one.

I recently bought a used epi SG G310. It has 2 volume and 2 tone controls. Now when I have the PU selector in the center, I figured I could dial in seperate volumes, to mix sounds from the neck and bridge pickups, but when in the center position if I turn either volume knob to 0, I get no sound.

Is this normal???
 
Is it "normal"...well, it's often the way they wire guitars with 2 + 2.
Personally, I never understood why that's the standard way for most manufacturers.
Seems kinda dumb to me, which is why I change all of mine so that each Volume is independent of the other...even in the middle position of the PU selector switch.

It's actually very easy to change...just swap the positions of each of the wires going to the two legs of each Volume pot (the third leg stays tied to ground).

IOW…the wire on the end leg swaps with the wire on the middle leg.
 
wow and diagrams as well...that is just awesome miroslav...thanks heaps, much appreciated. A great excuse to change the cheap pots and switch.
 
I hate guitars that have a separate volume for each pickup. I like all my guitars to be wired like a strat...one master volume and a separate tone for each pickup.
That's the way I have my les paul wired and it's much easier to gig with now.
 
I wire mine with separate volumes for each pickup and a master volume and tone.
 
Yes that is normal depending how your guitar is wired.

Changing your wiring affects your tone. I have been putting a Fender Guitar with a Les Paul p-90 circuit together and taken it apart and rewired it 5 times before settling on what I have now.

You can wire the pots in reverse so you can mix the two pickups with the switch in the middle position.

I tried that first and didn't care for the tone it gave me. I prefer the tone I am getting from the 1950's wiring.

google "les paul circuit" for 2 tone, 2 vol circuit variations.

There is what is known as the; 1950's, 1960's and modern circuits.
 
Thanks everybody. I kind of feel like a kid in a candy store now. I think I may go with the 50's wiring as it sounds like one can keep a bit more treble. The link that miroslav posted above shows the 50's wiring.

Thanks again.
 
miroslav said:
Personally, I never understood why that's the standard way for most manufacturers.
Click to expand...

Independent volume wiring affects the taper of the controls, I think the tones. If you don't fiddle/don't care, no problem, but the guys that really work their guitar controls get picky about how they interact.
 
But that's my point...you have MORE control with independant volume wiring....so I don't get why the general standard has them wired together...???

AFA the taper...that's a function of the pot design...I don't think independant VS combined wiring changes the taper of the pots...?
 
miroslav said:
But that's my point...you have MORE control with independant volume wiring....so I don't get why the general standard has them wired together...???

AFA the taper...that's a function of the pot design...I don't think independant VS combined wiring changes the taper of the pots...?
Click to expand...
here's a question ..... I have NO tone controls on my Custom Stinnett (don't use 'em so I left them off) ... just two volume knobs ... one for each p'up. (2 P-Rails) ..... will simply swapping those wires on the volume pots give me the same freedom of volume knob usage in the center position and does anyone see any reason it would affect my tone?
 
The "alternate" method that yields independent volume control has the side effect of loading down pickups as you decrease the volume. So yes, it will effect tone.

I prefer the "standard" method with some series resistors to limit the interaction between volume controls, but that approach has its limits as well.

Any choice with a passive circuit will be compromise of some type. I also like sticking a transformer in the guitar to lower the output impedance of the circuit, that lets me use larger values for series resistance, which means less pickup loading/interaction.
 
mshilarious said:
The "alternate" method that yields independent volume control has the side effect of loading down pickups as you decrease the volume. So yes, it will effect tone.
Click to expand...

OK...but I wouldn't say it changes the "taper"....and that's maybe only in the middle selector position when both PUs are chosen. It shouldn't load them down any differently than standard wiring when you select either the Neck or Bridge....right?

I just find that with individual volume control, when the PU selector is in the middle position, you still get a much wider range of combinations, of both volume and tonal control then with the standard wiring....though I rarely use the middle or bridge positions...but I still like it better than the standard setup.

There are a whole bunch of wiring options...so folks can try and find what they like best. Some guys dig the "50's" wiring because it retains more Treble when turning down the volume....but me, I"m always trying to dial out the damn treble!!! :D
 
No, taper and loading are very different. Let's consider just one pickup, say it's a 10K humbucker with a 500K log taper pot, no tone control, 1M load at the amp, treat all impedances as pure resistive and ignore stray capacitance. In other words, complete make-believe :D

A typical audio taper pot is something like 16% resistance at 50% rotation. So our 500K pot will split 420K/80K.

Standard wiring has the full pot resistance as the load on the pickup, and the amp connected to wiper. What is the net load on the pickup?

420K + (80K || 1M) = 494K

What about the signal drop across the pot? That is:

20 * log (74K / 494K) = -16.5dB

And what about output impedance? That is:

(10K + 420K) || 80K = 67K

The same figures for alternate wiring:

load on pickup:

(420K + 1M) || 80K = 76K

output impedance:

420K + (10K || 80K) = 429K

signal loss--this is more complicated, effectively you have a loss from the load on the pickup plus the loss due to output impedance, here is a simple version:

20 * log ( (10K / 90K) * (420K || 1M) ) = -4dB

It gets more complicated with the middle position since you have to consider the effects of the second 500K load.

But in conclusion, you can see that the widely varying pickup load and output impedance of the alternate wiring will yield substantially varying results once we consider the inductive source impedance of the pickup and the cable's capacitance. The result will be to shed highs much more rapidly than standard wiring. I imagine many people using alternate wiring resort to treble shunt or bypass caps to compensate.

I personally enjoy the treble response of a relatively unloaded, underwound (5K) humbucker. I can always roll off highs using a tone control (at the guitar or amp) if I want a different tone. In contrast, trying to recover HF response from a guitar wired to shed highs will usually yield poor signal to noise as a result.

Most of all, it's nice to have a volume control that acts solely like a volume control and a tone control that does the same. That is a difficult goal with passive wiring . . . I think the answer is a transformer, but not too many people see things my way.
 
OK...but that load and more rapid treble loss at the tone pot would only occur when the middle postion (both PUs) is selected...right?

In the neck or bridge positions, the load and tone operartion would yield the same results as if you had the volumes wired standard...right?

At least that's how it sounds to me, and I don't have a problem with that, because in the middle position, I gain the ability to dial in the volumes of two PU's with a lot more variety.
 
No, the treble loss would be mainly to cable capacitance and also resistive loading of the (inductive source) pickup. The tone control is secondary when at full (no cut). This is a single pickup example, dual pickups are more complex.

Bottom line, in a single-pickup (neck or bridge) setting, the results are potentially quite different in the two wiring configurations. That may or may not be desired.
 
Not sure if I'm following you.

The scenario is 2 humbuckers in a 2-Volume, 2-Tone configuration.

My question:

If the Volumes are wired for independent control when the PU selector is in the middle position VS the standard wiring of tying them together....
...will/won't the loading and tone you speak of only apply when the selector is in the middle postion, but when it's set for either neck or bridge, the loading and tone should be the same with independently wired Volumes as it is with standard wiring...yes or no?
 
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