250 K Volume, 500 K Tone

[boris bubbanov]

I was thinking about posting this on the Strat side, but since they're always on 10, I had second thoughts.

Here's my idea. The volume control, as it backs off, loses treble. That effect could be reduced a lot if the tone pot were 1 meg. But then the tone pot is basically an on off switch. What about a 500 K tone pot?

Much obliged!

[bradpdx]

Originally Posted by boris bubbanov

Here's my idea. The volume control, as it backs off, loses treble. That effect could be reduced a lot if the tone pot were 1 meg. But then the tone pot is basically an on off switch. What about a 500 K tone pot?

Much obliged!

You have it backwards. The larger the value of the volume pot, the MORE severe the treble loss as it is turned down, assuming that there is no compensation circuit (e.g., bypass cap/resistor)

A 1 Meg volume pot will result in a brighter sound when full up and a rapid decrease in treble as it is turned down, due to the interaction with cable capacitance.

The lower the value of the volume pot, the smaller the resistance and the less interaction with the cable. That is why active circuits (like EMG pickups) use very low value pots - 25K. They can guarantee consistent treble at all levels with any reasonable length of cable.

Fender's choice of 250K volume pots was a compromise aimed at preserving enough pickup brightness while allowing a reasonable level of treble loss. Personally I use compensation networks on the volume control (series resistor/cap) to make it more even as it is turned down.

Tone pots are different, as they are simply a load on the pickup and do not interact with the cable. Very high value tone pots have less of an effect until they are turned down quite low, as they do not represent a significant load on the pickup. Above some reasonable value (perhaps 1Meg or 500K) increasing the value of the tone pot has no effect, as the cable and volume pot dominate pickup behavior.

I do not higher value tone pots because a) the Tele is bright enough already b) I like the tone control to provide useful changes in the first 1/3 turn or so. If the pot is very large, then I can only use the bottom 1/3 and it is more difficult to adjust quickly on onstage, IMHO.

[RatherBeFishing]

Isn't the 50s mod supposed to help with this very thing? You might give it a try if you haven't already. I'm sure you're familiar with it but here it is.





I remember reading a thread recently where someone used used 250k and 500k pots to get the same effect as using 375k pots.

[boris bubbanov]

Originally Posted by bradpdx

Tone pots are different, as they are simply a load on the pickup and do not interact with the cable. Very high value tone pots have less of an effect until they are turned down quite low, as they do not represent a significant load on the pickup. Above some reasonable value (perhaps 1Meg or 500K) increasing the value of the tone pot has no effect, as the cable and volume pot dominate pickup behavior.

I do not higher value tone pots because a) the Tele is bright enough already b) I like the tone control to provide useful changes in the first 1/3 turn or so. If the pot is very large, then I can only use the bottom 1/3 and it is more difficult to adjust quickly on onstage, IMHO.

Thanks, I should have remembered the tone pot is not in series with the cable.

Believe me, I never gave any consideration to departing from my 250 K volume pots; as a matter of fact, I just converted a used MIM 69 Thinline to 250 K pots, something I meant to do the moment I got the guitar.

Much obliged.

[telbert twang]

The 50-ies mod unfortunately for some reason didnt work with my tele (which has 500 pots and .047 cap, could these influent?) , i checked it 3 times and couldnt see any flaw in soldering etc, it just did not work ( vol rolldown still brought muddyness )

[altouchet]

I am installing a neck humbucker on my tele and replacing the bridge pickup with a blade style such as the lil' puncher vintage modern. Do I need to change pots to 500K? What is your opinion?
Al

[RatherBeFishing]

Originally Posted by telbert twang

The 50-ies mod unfortunately for some reason didnt work with my tele (which has 500 pots and .047 cap, could these influent?) , i checked it 3 times and couldnt see any flaw in soldering etc, it just did not work ( vol rolldown still brought muddyness )

As stated above, the 500k pots will have a more extreme treble loss as rolled down so maybe that is the culprit? I'm not sure that would be the cause but it is worth giving 250k pots a try.

Also, I've read that .1uf cap works well with this. It is worth checking one more time to see that you have them wired up correctly as I have made the mistake of wiring to the wrong lugs.

[tdowns]

Originally Posted by bradpdx

You have it backwards. The larger the value of the volume pot, the MORE severe the treble loss as it is turned down, assuming that there is no compensation circuit (e.g., bypass cap/resistor)

A 1 Meg volume pot will result in a brighter sound when full up and a rapid decrease in treble as it is turned down, due to the interaction with cable capacitance.

The lower the value of the volume pot, the smaller the resistance and the less interaction with the cable. That is why active circuits (like EMG pickups) use very low value pots - 25K. They can guarantee consistent treble at all levels with any reasonable length of cable.

Fender's choice of 250K volume pots was a compromise aimed at preserving enough pickup brightness while allowing a reasonable level of treble loss. Personally I use compensation networks on the volume control (series resistor/cap) to make it more even as it is turned down.

Tone pots are different, as they are simply a load on the pickup and do not interact with the cable. Very high value tone pots have less of an effect until they are turned down quite low, as they do not represent a significant load on the pickup. Above some reasonable value (perhaps 1Meg or 500K) increasing the value of the tone pot has no effect, as the cable and volume pot dominate pickup behavior.

I do not higher value tone pots because a) the Tele is bright enough already b) I like the tone control to provide useful changes in the first 1/3 turn or so. If the pot is very large, then I can only use the bottom 1/3 and it is more difficult to adjust quickly on onstage, IMHO.

I know anything related to politics is not allowed on this forum, but I'll have to say.....


I'm Terry Downs, and I approve of this message.

Good posting there bradpdx. If one desires more of a treble peak from the Tele, 500K and 1 meg volume pots are OK. One just needs to carefully consider a resistor/capacitor treble bleed to even out the response when turned down.

[Rob DiStefano]

What bradpdx said ... I'll add that I like using a no-load tone pot.

[HighTower]

I recently bought a nice gold duo of knobs with pearl top; they look nice but I ran into problems. The pots are on a MIM standard and the knobs had too small of holes to mate with the pot stems. After much filing I got the volume pot to seat, but I broke the tone pot when filing it. What is the best way to do this? Do the standard pots have larger stems than the vintage? And exactly what pot should I get to replace the broken one?

[spankdplank]

I have an all stock 68 with two 1 meg pots, a .05 tone cap and the .001 treble bleed cap. Because it is all stock, I don't want to change pots or or do any serious rewiring. However, I do gig with it and want it to be usable on the fly. I found that with the treble bleed, when I roll down the volume a bit, the bass and "balls" decrease but the perceived volume does not go down that much. This requires me to roll back on the tone knob every time I decrease the volume. To get around this I took out the treble bleed cap (yes--I saved it). Now my volume knob is really only usable for about 1/3rd of a turn. Its almost an on/off but at least I don't have to adjust the tone everytime time I roll back the volume.

Question--is there a cap value or cap/resistor I could put in place of the old .001 treble bleed cap that would make the 1 megs act more like 250K or even 500K pots? Thanks.

Finally--Boris--sorry for the hijack if this is a bit off topic.

[boris bubbanov]

Originally Posted by spankdplank

Finally--Boris--sorry for the hijack if this is a bit off topic.

No sweat at all. Brad, Terry and Rob took this one and transformed it into something useful, what would otherwise have been a goofy thread.

I'd love to know the answer as well.

[bradpdx]

Originally Posted by tdowns

I

I'm Terry Downs, and I approve of this message.

Garsh, thanks!

[bradpdx]

Originally Posted by spankdplank

I have an all stock 68 with two 1 meg pots, a .05 tone cap and the .001 treble bleed cap.

Question--is there a cap value or cap/resistor I could put in place of the old .001 treble bleed cap that would make the 1 megs act more like 250K or even 500K pots? Thanks.

Good compensation is always subjective, and I haven't gigged with enough 1Meg pots to feel confident about this. But my first order guess would be to insert a resistor in SERIES with the .001mfd cap. The value should be between around 100K to 220K - start with 120K and see. The larger the resistor, the more subtle the effect of the cap.

Or you could gently unsolder and remove the old volume/tone pots, put them in a Ziploc, and replace them with 250K/250K pots. You can always put the originals back.

[spankdplank]

Thanks Bradpdx. The resistor sounds like a good idea, as I don't wan't to break the original sodder points in order to put in 250K pots and the resistor and .001 cap in series would have the same sodder points as the original cap. Does it matter if the order of the connection from the outside lug to the middle lug is resistor/cap or cap/resistor? It was also suggested that I replace the .001 cap with a .002 cap, in the same place and no resistor. Any thought on this mod?

[tdowns]

Originally Posted by bradpdx

Good compensation is always subjective, and I haven't gigged with enough 1Meg pots to feel confident about this. But my first order guess would be to insert a resistor in SERIES with the .001mfd cap. The value should be between around 100K to 220K - start with 120K and see. The larger the resistor, the more subtle the effect of the cap.

......

I have used 1 meg pots quite a bit. As bradpx mentioned, it is very subjective to do compensation networks. I've always used a resistor in PARALLEL with the treble bypass cap. I've mostly settled with a 0.001µF cap and a 330K resistor in PARALLEL. When the volume pot is max CW, the resistor and cap are obviously not in the circuit. As the volume is turned down, the effective load on the pickup is lowered with the parallel resistor, and the series resistance to the output is less with the 330K. It improves the overall taper. I just connected a "test 1 meg pot" in parallel with the treble bypass cap and tweaked it until I got the best response in taper and minimal tone change when turning down the volume. I disconnected the "test 1 meg pot", read it's value, and found the nearest fixed resistor to install in its place.

Indeed YMMV.

Also remember, the length/capacitance of your guitar cable and amp/effect load capacitance with affect this as well.

[braderrick]

Originally Posted by spankdplank

Thanks Bradpdx. The resistor sounds like a good idea, as I don't wan't to break the original sodder points in order to put in 250K pots and the resistor and .001 cap in series would have the same sodder points as the original cap. Does it matter if the order of the connection from the outside lug to the middle lug is resistor/cap or cap/resistor? It was also suggested that I replace the .001 cap with a .002 cap, in the same place and no resistor. Any thought on this mod?

Hey I just bought a bunch of 220k resistors and .001 caps. Shoot me a PM with your address and I'll send ya a couple so you can try them in both series and parallel. I've been installing mine in parallel.

[spankdplank]

Many, many thanks, Braderrick--PM sent. Terry Downs--Thanks for the info. If the resistor in series works for you, I'm sure sure it will work for me just fine.

[tdowns]

Originally Posted by spankdplank

...... Terry Downs--Thanks for the info. If the resistor in series works for you, I'm sure sure it will work for me just fine.

Just to clarify, I used a resistor in PARALLEL with the treble bypass cap. No in series.

[spankdplank]

PARALLEL--got it. Typing/multitasking at work. Sorry for the mistype.