Tone Knob: Valuable or not?

Keith Murch

I have ordered replacement pots from Stewmac. They have lots of info on how to select the right ones in their website:
http://www.stewmac.com/shop/Electronics,_pickups/Potentiometers.html
Keith

MattHenry

Thanks, Keith! I'll give Joe a chance to send me some working replacements first and then go that route if I need to. The old volume pot also suffered from that ninety percent quieter in the first quarter turn problem so it's disappointing to have all new hardware and no improvement there.

Buco, Craig needed to wire the tone pot backwards because the it was half dead on arrival so it wouldn't function in the traditional brighter-going-clockwise direction.

Al Watsky

Your down the rabbit hole now.
These days the best choice for pick guard mounted volume and tone controls are the small roller wheels that mount under the guard. The knobs on the guard just get in the way.
There are only 2 different values for vol and tone pots. 250k and 500k . In this mini format thats all you have. In the standard format there is also a 330k unit that is used for tone controls.
What will get you more usable sweeps on any control type you use is a combination of resistance and capacitance on the pot between the first 2 legs. The Cap controls high pass and the resistance adjusts midrange through the sweep. The frequencies passing will have a large effect on what you finally hear in the sweep of the pot.
We use different values based on listening tests.
There are standard values, but listening is the final factor.
Also be aware that your cable will have a real effect on the circuit load and therefore the tone of the circuit.
All this stuff us available from Mouser electronics. For pennies on the dollar .
The OP asked about the value/usefulness of a tone pot.
My answer is this.
Sure its great to have a tone pot if it doesn't get in your way on the guard. On the other hand if you adjust your amp to your liking you can get lots of tonal variation by moving your right hand.
If the volume pot doesn't have a high pass cap it will function as a tone pot by rolling off highs as the volume is lowered. Many people count on that as a means of shaping their sound. Its passive and simply requires balancing the amp volume and tone with the results desired , simple and effective.
A tone pot is "nice" but not necessary.

MattHenry

Thanks for the detailed input, Al. I guess I should have opted for the wheels, which I think you or someone had suggested early in the thread. I was trying to keep an old school look with the kit from Archtop.com.

I don't know what "audio taper" means. I was just thinking I could turn the volume knob halfway and reduce the volume by half.

Were you saying that volume and tone knobs start working this poorly with some cables? Strange that I've never noticed before.

Al Watsky

Its a tone difference not a sweep difference.
Different pots react differently to different pickups due to the construction of the pickup coil.
So you match the pot to the coil in practice.
Any pot works to one degree or another.
An audio taper is nomal for a volume pot.
Some folks I know have used LOG pots for tone, but its not a big deal.
Most likely you need a high pass cap/resistor on the volume pot, then you would hear a smoother taper of volume because the pot value would not roll off all your highs the minute you turn it down just a little bit. Thats what your hearing. It very simple, any tech should be able to do that for you. Some one that has had real experience with electric guitars and their circuits.
Not rocket science.

MattHenry

Thanks again, Al!

Joe is sending replacement pots today and I'll ask Craig to consider that high pass cap-resistor when he swaps them out.

MattHenry

Really helpful info, Al.

So I'm looking to order something like this:
http://www.stewmac.com/shop/Electronics,_pickups/Components:_Caps_(capacitors)/Golden_Age_Treble_Bleed_Circuit.html

And do something like this:
http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=40430&g2_serialNumber=1

Is that the idea?

Would it help to take a similar approach with the tone knob? The current one only works when wired backwards so it's gonna be replaced, but as is it still functions very poorly, with all the darkness arriving in the final quarter turn.

Al Watsky

More like the second one.
The first one helps but the combination of cap and res is what you want.
AFA the values go?
I've used different values for the resistor and gotten different midrange results.
I'm a cook book electronics guy.
I just try something in the suggested range and try that. Then I might go up or down a value or so to give a listen before I zip it up.
Its a season to taste kind of thing.
Some guys like one thing some another.
The cap is usually the small .001 cap is standard, I see stewmack has settled on the 150 value for the resistor.
That may be to your liking.
That being said, 5 bucks for 5cents of parts is sharp practice at best.
I buy this stuff by the bag from parts suppliers.
This is cheep stuff. Go to radio shack.
Some players hate treble bleed circuits BTW. Not everybody likes the same stuff.
I have them in my electrics. Works for me.

MattHenry

Do you recommend using both a cap and a resistor for tone as well?

This wiring diagram from Bartolini's site looks helpful:
http://www.bartolini.net/wp-content/uploads/2013/12/1-Conductor-Wiring-Diagram.pdf

So you'd recommend wiring it like that but with a resistor as the second leg on the Treble Bypass Capacitor and possibly also on the Treble Cut Capacitor heading to the tone pot.

Also, you prefer them wired sequentially, first the cap and then the resistor, rather than stacked like the Golden Age Treble Bleed mod at StewMac.

Radio Shack does have better prices too.

Thanks again, Al.

Al Watsky

No resistor needed for tone.
Like the StewMac version .
Its all theory till you hear it.
Especially the tone cap.
Stick to the small caps.
Those huge orange caps and oil caps are useless in a pick guard mount situation and they don't sound that much different anyway. Some folks say not at all.
Good luck.