Electronics upgrades

Just about to pull the trigger on a purchase and have a couple of basic questions about the kits and setting up electronics.

- Shielding: I know I want to do it, but does is it best achieved with the copper shielding, shielded wires, both, something else altogether?
- Pots and capacitors: what sort of change is there to tone etc? Is it just a general improvement and smoothing, a good spend of a few dollars? Is there any sort of rule about which capacitors shift sounds towards different ends of the spectrum or styles?

Which guitar are you thinking of buying? much easier to recommend values etc

First, yes to copper shielding in the control cavity. I also like to use braided shield wire for he longer runs, such as from the switch on LP, SG and EX type Guitars..

Second, wot Tony sed :)

Thanks DB and Tony.
Thinking a LP1 as a first build, aiming for classic blues-rock tones.

@ DB it's really only LP builds that have a long run switch to control cavity. The SG and EX out of the factory have the switch in the control cavity, unless modified of course !
@ SG, yes to copper shielding, pot upgrades are worthwhile and not very expensive, as are caps so get 2 or 3 different value caps and experiment to find the sound you want
EDIT just saw you are looking at a LP-1, worth using braided wire for the switch wires to the control cavity and they are long runs

Ok being a blues rock player myslef here's what i would do.

Shield the pickup cavities with copper, an easy job

I use Shielded braid wire, with some heat shrink around it so it doesnt short

pots 500k caps .022

You can't go wrong with the suggestions above. I have also used Alu tape, which is cheap, but hard to solder. One of the most important things to do is ground EVERYTHING. The shielding, bridge, braded wire, pots, etc all need to be grounded to the ring on the jack.

Whether your caps are orange or green doesn't matter much, but the value does. .22 is a good place to start. Use a higher value to get a darker/fatter tone, lower value for a brighter tone.

500K is the standard pot for humbuckers. If that's too dark you can go to 1meg, if it's too bright go down to 250K.

Pots come in "linear" and "audio" flavors. For me both tone and volume have a smoother roll off with audio tapers. That said, with a linear pot the roll can feel like it's all in the first quarter turn--which some people like. You will for sure hear the difference between the two.

One thing I have learned the hard way is that not all pots that say they are 500K spec that way. I always check pots on an ohm meter before putting them in the guitar. If your 500k pot specs at 520K don't worry, but if it specs at 400K you'll hear a difference.

Pots also feel different. CTS pots turn harder because of the way they are constructed. Bourns (and most others) turn easier.

I have also learned to check with the ohm meter to make sure that what I think is an audio pot really is one. A 500K linear pot will show 250K when you turn it to the half way point. An audio pot will hit 250K well past that point. Not every pot stamped with an "A" is really an audio pot...

Thanks all, very useful, I'll keep you posted on how it goes!

well done Fender3x you made some very good points, I will check my pots on a multimeter next time I'm wiring

I hear that Bourns have dropped the a & b designations due to there not being that much of an advantage in having them.
Perhaps one of our more knowledgable electrical gurus can answer this?

Anyhoo, I only use Bourns these days, unless I am working on a vintage axe in which case I try to match what was there.

Last batch of CTS pots I got were no better than Alphas, which I really dont like at all.. Scratchy and horrible to the touch..

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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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.

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...

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.

Quote:

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Originally Posted by 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...

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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).

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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Quote:

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Originally Posted by 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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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.

#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.

Quote:

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Originally Posted by 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.

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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.