Electronics upgrades

[fender3x]

What I have always liked about the CTS pots is that you can swap out the resistor wafers. That allows you to put any CTS wafer in any CTS housing. I have used this for "building" stacked pots or push pull pots even when I could not find them with the values or tapers I wanted.

That said, I haven't ordered them for a while. The quality of the housings don't very much between the various brands but the quality control very well may.

None of the major brands are sealed. I generally shoot mine full of lubricated contact clenaner if I hear scatchiness.

I'd have been tempted to try PEC pots, which are "mil spec" and sealed, and may do a bit better, but they are a tad pricy...and I am pretty cheap I need minis for my current project and the PECs I have found are $25 US. You can sometimes find common values for less, but I have only seen those in full size.

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[tonyw]

You can get Audio and Linear in the Bourns Pro Audio pots

I use Bourns no loads alot these days but i have everything people want, Alpha, CTS, and Bourns and i match them in sets, school kids with no $$ arnt going to pay a bomb for pots..

I am going to be using the Bourns Vintage 82 series pot in future on my guitars but they are $$$$$

This 250k ohm pot comes with a knurled 24 spline split-shaft, low noise long life conductive polymer element, audio taper, and has a sealed composite housing. High quality manufacture with 10% total resistance tolerance. US spec. bushing.

I will pretty much be only using Bourns in my guitars, after i run out of C.T.S (not all CTS are the same) and i have some old CTS pots here that are NOS to go into some teles i am thinking about.

[Rabbitz]

There are two types of "pots". Linear and Log (logarithmic) - I assume log = a and linear =b.

Linear have a linear progression of resistance, and log it is logarithmic.

Thus the "all at one end" effect. Linear or log could create this effect depending on what the circuit is.

To explain the difference, if you divide the rotation of the variable resistor into 10 positions and measure the resistance at each of those positions the results would look a bit like (I hope this works):
Pos....Log...Lin
1.......1.....1
2.......2.....50
3.......4.....100
4.......8.....150
5.......16...200
6.......32...250
7.......64...300
8.......128..350
9.......256..400
10.....512...500

Ok the maths didn't work out but you get the idea...

[fender3x]

log=audio. I don't think it's literally a curve (even though that's what the mfgs publish on their website). It's more like two or three straight lines to approximate the curve.

Those sealed bourns pots look nice...and they are small, too, which is nice... I see them for around ~$17 US. Is that what you folks are mostly using? I ordered a mini in the more conventional non-sealed variety to take a looks at and do some comparisons. But these look close to mil-spec.

[DrNomis_44]

There are two types of "pots". Linear and Log (logarithmic) - I assume log = a and linear =b.

Linear have a linear progression of resistance, and log it is logarithmic.

Thus the "all at one end" effect. Linear or log could create this effect depending on what the circuit is.

To explain the difference, if you divide the rotation of the variable resistor into 10 positions and measure the resistance at each of those positions the results would look a bit like (I hope this works):
Pos....Log...Lin
1.......1.....1
2.......2.....50
3.......4.....100
4.......8.....150
5.......16...200
6.......32...250
7.......64...300
8.......128..350
9.......256..400
10.....512...500

Ok the maths didn't work out but you get the idea...

That is actually good enough to use as an example, standard pots generally have a tolerance of about 20% plus or minus the marked value.



On the subject of shielding, if you're adding some shielding to a Strat scratchplate but don't have any copper shielding tape, you can use ordinary kitchen aluminium foil, you basically remove everything from the scratchplate, then spread some kwik-grip contact cement on underside of the scratchplate and then cover that with the kitchen foil, the foil will stick to the contact cement, all you have to do now is use a pocket knife to remove the foil from the pickup holes, the pot holes, etc, then re-install all the electronics, the foil will be connected to circuit-ground via the pots so you don't need to do any soldering to it (the solder won't take to the foil anyway).

[fender3x]

For sure the alu-foil and contact cement will work, and it's as good as copper tape electrically. It also appeals to the cheapskate in me.

What I have been using lately is aluminum tape. You can get 30 yards of 2 inch aluminum tape for around $8 US. That's enough to do about half the PBG inventory ;-)

http://m.harborfreight.com/2-inch-x-...not%20provided

It's easy to get since it's used in HVAC work, so any home improvement store should have it.

The sticky side is conductive, so if you stick one piece partly over another it will form a continuous circuit without soldering. The only advantage to copper tape is that it is easier to solder on a ground wire, although soldering the copper tape is not that easy either IMO.

I get around the ground problem by driving a small screw through the foil somewhere and attaching a ground wire to the screw.

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[Taswegian]

For sure the alu-foil and contact cement will work, and it's as good as copper tape electrically. It also appeals to the cheapskate in me.

What I have been using lately is aluminum tape. You can get 30 yards of 2 inch aluminum tape for around $8 US. That's enough to do about half the PBG inventory ;-)

http://m.harborfreight.com/2-inch-x-...not%20provided

It's easy to get since it's used in HVAC work, so any home improvement store should have it.

The sticky side is conductive, so if you stick one piece partly over another it will form a continuous circuit without soldering. The only advantage to copper tape is that it is easier to solder on a ground wire, although soldering the copper tape is not that easy either IMO.

I get around the ground problem by driving a small screw through the foil somewhere and attaching a ground wire to the screw.

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Garden centres sell adhesive backed copper tape about 1" (25mm) by several metres for under $10. It's slug repellent. You stick it around the rim of your plant pots. I shielded my Strat copy with it. A few solder blobs across the joins because the adhesive may not be conductive, but it takes solder really well.

[tonyw]

#1. The basic sixty cycle hum caused by single coil pickups.
#2. Humbuzz A caused by unshielded circuits
#3. Humbuzz B caused by inferior light dimmers.


How can we solve these problems?

#1. Use a dual coil system to neutralize external magnetic fields. Shielding does not reduce the hum.
#2. Humbuzz A can be eliminated by shielding with either coppertape or conductive paint.
#3. Humbuzz B can be only eliminated by shielding the circuit including the cavities below the pickup with aluminum tape.

[dingobass]

You can get Audio and Linear in the Bourns Pro Audio pots

I use Bourns no loads alot these days but i have everything people want, Alpha, CTS, and Bourns and i match them in sets, school kids with no $$ arnt going to pay a bomb for pots..

I am going to be using the Bourns Vintage 82 series pot in future on my guitars but they are $$$$$

This 250k ohm pot comes with a knurled 24 spline split-shaft, low noise long life conductive polymer element, audio taper, and has a sealed composite housing. High quality manufacture with 10% total resistance tolerance. US spec. bushing.

I will pretty much be only using Bourns in my guitars, after i run out of C.T.S (not all CTS are the same) and i have some old CTS pots here that are NOS to go into some teles i am thinking about.

I am with Tony on this.
Bournes minis are my go to pot for most builds, unless it is a restoration or repair on a vintage instrument in which case I go for the vintage style CTS.

On my top end builds I will use Bournes sealed pots. These puppies are not really expensive when we are talking about a 5-6k custom build.

I ran the multimeter over the last batch of Bournes minis and they were all within %5.

What is interesting is there are Bournes, and then there are Bournes...
The ones I get directly from Bournes seem to be more accurate than the ones I get elsewhere.
Makes me think that the ones I get from Guitar parts dealers may be second party manufacture.
Still good though, never had one more than %10 either way.

It is also a good idea to try and match or pair your pots, especially if you use CTS or Alphas... These guys can be anywhere up to %20 out.