Bright cap vs lugs

[fdesalvo]

I've seen some place the bright cap across the outer lugs of the volume pot, while others use the outer/inner lugs.  Why the discrepancy? 

[thelonious]

Do you mean that on some the cap is placed from lug 1 to lug 3 (outer lug to outer lug) instead of from lug 1 to lug 2 (outer to inner)? Because it seems like lug 1 to lug 3 would short high frequencies to ground and act as a LPF instead of a bright cap---if lug 3 is in fact connected to ground, and I am correctly interpreting what you mean.

[fdesalvo]

Yep that's what I mean. Just curious. I might move mine around and see if there's a difference.

[sluckey]

If you put it on the outer lugs it will become a dull cap.

The bright cap only works when connected across the ungrounded lugs of the volume pot. You may want to use a switch like this...

[fdesalvo]

If you put it on the outer lugs it will become a dull cap.

The bright cap only works when connected across the ungrounded lugs of the volume pot. You may want to use a switch like this...

Interesting indeed!  I've only got a 500pf and a 250pf cap laying about.  I know the trad bf value is ~120pf.  Wondering if the 250pf will be too bright!  Only one way to find out.

[birt]

wire both caps in series and you end up with about 167pF

[fdesalvo]

wire both caps in series and you end up with about 167pF

Thank you.  I was also thinking about possible setting up a switch to choose between a couple caps - might come in handy since we play so many venues that have various cabs in the backline.  I just whipped this up - does this look right?



Thanks!

[sluckey]

I was also thinking about possible setting up a switch to choose between a couple caps

That's a good idea.

[thelonious]

Cool. I like the switched cap options idea. Or if you settle on one cap value that you like a lot, I think you could get switchable levels of boost by wiring a resistor in series as below. Does that look right?

[fdesalvo]

I like where this is going. Just finished messing with some brigh cap options.  

500pf or 250pf = pure pain

250pf + 250pf in series = just right. Able to turn down treble pot, giving more range to other tone controls.  In other words...about 125pf lol I guess fender knew what they were doing??

I ordered a CTS 1MA push-pul pot since I already had my faceplate made up.  Kinda sad to remove that sweet PEC!

[The_Gaz]

Another cool trick, especially with the push-pull pots is to replace the green wire in your  drawing with a resistor (try 47K-1M). This puts a resistor in series with bright cap, which boosts the same frequenter, but limits the 'height' or amount of boost.

And in regards to your first post wiring a cap on the outer lugs (just because it's on the lugs does not make it a bright cap) is just a convenient place to wire a cap to ground to cut highs, ad the rotation of the pot will have no effect on the cap. On the other hand (or other lugs I should say) - the wiper and ground lugs - the sound will get darker as you turn up the volume, this can be very useful in certain amps that get brittle or fizzy when cranked up too much. Of course you can always use a bright and dark cap i conjunction!

[fdesalvo]

Thanks for your insight! 

I imagine once could use this idea to create a mid shift type arrangement on the mid pot, too.

Another cool trick, especially with the push-pull pots is to replace the green wire in your  drawing with a resistor (try 47K-1M). This puts a resistor in series with bright cap, which boosts the same frequenter, but limits the 'height' or amount of boost.

And in regards to your first post wiring a cap on the outer lugs (just because it's on the lugs does not make it a bright cap) is just a convenient place to wire a cap to ground to cut highs, ad the rotation of the pot will have no effect on the cap. On the other hand (or other lugs I should say) - the wiper and ground lugs - the sound will get darker as you turn up the volume, this can be very useful in certain amps that get brittle or fizzy when cranked up too much. Of course you can always use a bright and dark cap i conjunction!

[Ed_Chambley]

Here is a little deal I use.

[fdesalvo]

Way cool, Ed. :)

I ended up tossin the bright cap idea altogether.  I went down in value until I hit 50pf and still found it too trebly.   Sort of wish I had a presence pot, but honestly the amp sounds just fine without it.