Alternative methods to solder to back of pot can these work?

[shoulderpet]

I have always found soldering to the back of a pot to be tricky, I found a couple of cheat methods on Youtube and wondering if these can work, hoping someone more knowledgeable than me can advise

 

Method 1 - This method I saw the person said you solder to some copper tape, the copper tape then gets attached to the back of the pot, does this work? Is this a good way of attaching ground wires and could this also work with capacitors which usually have one of there legs soldered to the back of the pot, could you solder the one leg of the capacitor to the copper tape and then attached that to the pot?

 

Method 2 - In this method the person soldered a thin guitar string from one lug of the pot to the back of the pot, does this work? could you use this method to attach a ground wire by soldering the ground wire onto the string rather than the back of the pot(I am guessing it needs more direct contact with the pot)? Can you use this method to attach a capacitor by soldering the capacitor onto the string rather than the back of the pot?

 

Thank you

[paul_5]

broadly speaking, anything that's conductive will work. I've always found that roughing up the back of the pot (sandpaper or a small file) takes the plating off the back, and allows the solder to attach to the metal better.

[rmorris]

For the Copper Tape solution you first need to be certain that the adhesive is conductive. Some types are and some aren't.

Soldering the wire to the tape should be fine. The possible problem you may have  is a secure adhesive connection.

Do key the pot casing to remove any coating / grease etc. But you'll still have a relatively small flat surface to fix the tape.

Really 'squeegee' it down.

I'd advise soldering the connection myself. Use a good sized. preferably temperature controlled iron.

If it's a configuration where you are attaching one of the pot lugs to the casing to ground it - then bend the lug over to solder that. Then the wire can be more easily soldered to the lug using the hole in it to keep the wire in place.

[shoulderpet]

Ok thanks, I assume also that soldering a capacitor to the copper tape should also be fine?

Another thing that I have just thought of is that most of the time there is a ground wire soldered from the back of the tone pot to the underneath of the bridge, could I instead have the ground wire that would usually go to the back of the pot to the bridge wired from the output jack to the bridge? 

 

Edited March 16, 2022 by shoulderpet

[rmorris]

2 hours ago, shoulderpet said:

Ok thanks, I assume also that soldering a capacitor to the copper tape should also be fine?

Another thing that I have just thought of is that most of the time there is a ground wire soldered from the back of the tone pot to the underneath of the bridge, could I instead have the ground wire that would usually go to the back of the pot to the bridge wired from the output jack to the bridge? 

 

 

Yes (to the 0V connection (screen) of course.

Be careful not to connect to the Ring Connection by mistake.

[shoulderpet]

58 minutes ago, rmorris said:

 

Yes (to the 0V connection (screen) of course.

Be careful not to connect to the Ring Connection by mistake.

Sorry you lost me there, apologies I am a bit of a newb to all this, would you be able to elaborate on what you mean by this, thank you

[PaulThePlug]

Solder Tag style washers... Like the ones used on the Bornes Plastic Bodied pots of their 'Vintage' Range.

https://www.bourns.com/docs/product-datasheets/82.pdf&ved=2ahUKEwj337rPh8v2AhUShlwKHWmvAjQQFnoECBoQAQ&usg=AOvVaw0Q3lXe_hfqCiINQRmbu9lp

 

Edited March 16, 2022 by PaulThePlug

[Dan Dare]

7 hours ago, paul_5 said:

I've always found that roughing up the back of the pot (sandpaper or a small file) takes the plating off the back, and allows the solder to attach to the metal better.

 

This works for me, too. Tin the wire and back of the pot and it should be easy.

[rmorris]

16 hours ago, shoulderpet said:

Sorry you lost me there, apologies I am a bit of a newb to all this, would you be able to elaborate on what you mean by this, thank you

 

Well I was being rather brief so no problem.

This really applies only to active basses that use a 'stereo' jack for the output and the screen connection of a mono jack plug is used to join the 'Ring' conductor to 'Screen' to complete the power circuit - hence the usual advice to unplug when not used inn order to avoid running batteries down quickly. So I'm just advising to wire to the 'Screen' connection on the output jack and not the 'Ring' connection.

For clarity - 'Stereo' or 'Balanced' jack connections are referred to as "TRS" jacks.

T = Tip (Signal +ve)

R = Ring (next 'band' on the plug - Signal -ve for balanced audio; other channel for stereo)

S = Screen

 

To add to the fun also often used as combined Send/Return connector for unbalanced Insert points on mixers.

[BigRedX]

Do you actually need to solder to the back of the pot for electrical (screening or earthing) reasons?

 

I always thought it was done simply because it presented a suitably large area for attaching all the various earth connections which would include the braided screen from the pick up(s) which might be tricky if you were just rely on the pot contacts to make all the joints.

[neepheid]

Honestly, I'd say get an old pot and get practicing so that you get better at doing it properly instead of trying to find workarounds.  The fact that you yourself referred to them as "cheat methods" implies that you know you should be doing it the correct way.

 

+1 for roughing up the casing at the solder point before starting.

 

Also, lead free solder is (in my experience) awful.  I still have a stash of old skool leaded solder and it works great.

[itu]

The easiest option is to buy a decent iron, powerful enough, say a 40 - 60 W unit. Big power equals short soldering times. Pots can take the extra power when the time is short.

[rmorris]

2 hours ago, BigRedX said:

Do you actually need to solder to the back of the pot for electrical (screening or earthing) reasons?

 

I always thought it was done simply because it presented a suitably large area for attaching all the various earth connections which would include the braided screen from the pick up(s) which might be tricky if you were just rely on the pot contacts to make all the joints.

 

There's an advantage to having the pot case grounded (albeit small if the cavity itself is shielded and grounded effectively) but it doesn't need to be the place where all the ground/screen connections join.

[rmorris]

2 hours ago, neepheid said:

 

Also, lead free solder is (in my experience) awful.  I still have a stash of old skool leaded solder and it works great.

For Lead Free you just need a hooter iron basically. A 'standard' 25W Antex or similar may struggle. You do need to keep more of an eye on the condition of the solder iron tip though.

[paul_5]

5 hours ago, BigRedX said:

Do you actually need to solder to the back of the pot for electrical (screening or earthing) reasons?

 

I always thought it was done simply because it presented a suitably large area for attaching all the various earth connections which would include the braided screen from the pick up(s) which might be tricky if you were just rely on the pot contacts to make all the joints.

 

Not necessarily. Jazz basses with the metal 'Bell Plate' provide a mahoosive ground connection to the pots, because both the output jack and the pots are in contact with it the whole time. This is fine until a pot comes loose on a gig, and you start to get intermittent drop-out.

 

P basses tend to have plastic plates with a thin layer of conductive foil on the back, so in theory should be grounded via this.

 

Soldering wires between the 0V (ring of the output jack) and the pots shouldn't strictly be necessary, but it's a 'belt and braces' approach that I prefer.

Edited March 17, 2022 by paul_5

[itu]

6 hours ago, paul_5 said:

Jazz basses with the metal 'Bell Plate' provide a mahoosive ground connection to the pots, because both the output jack and the pots are in contact with it the whole time. This is fine until a pot comes loose on a gig, and you start to get intermittent drop-out.

Exactly. A pot not soldered = problems. Sooner or later.

[adamg67]

On 17/03/2022 at 12:22, itu said:

The easiest option is to buy a decent iron, powerful enough, say a 40 - 60 W unit. Big power equals short soldering times. Pots can take the extra power when the time is short.

 

I used to find soldering to the back of pots a pain, and then I bought a decent solder station and spent a bit of time learning to solder properly, and hye presto it's pretty straightforward now.

 

Leaded solder all the way for me as well, you can still buy it no probs.

[itu]

4 hours ago, adamg67 said:

Leaded solder all the way for me as well, you can still buy it no probs.

Agree. I bought few kilos of 60/40 after hearing about this RoHS thing for us ordinary customers.

[BigRedX]

On 17/03/2022 at 15:29, paul_5 said:

 

Not necessarily. Jazz basses with the metal 'Bell Plate' provide a mahoosive ground connection to the pots, because both the output jack and the pots are in contact with it the whole time. This is fine until a pot comes loose on a gig, and you start to get intermittent drop-out.

 

P basses tend to have plastic plates with a thin layer of conductive foil on the back, so in theory should be grounded via this.

 

Soldering wires between the 0V (ring of the output jack) and the pots shouldn't strictly be necessary, but it's a 'belt and braces' approach that I prefer.

 

But you can still compete the circuit with wires without having to rely on the screening components or soldering to the back of the pots.

 

So is there any actual benefit? Or as I said in my first post is is simply a convenient place to join all the various earth connections together.

[paul_5]

The back of the pot is just a large, conductive surface area to solder too - in theory you could solder ALL of the ground wires together at the output socket, but it's just less fiddly to have a flat surface to solder to than trying to do it on its side as the socket.

[rmorris]

14 hours ago, paul_5 said:

The back of the pot is just a large, conductive surface area to solder too - in theory you could solder ALL of the ground wires together at the output socket, but it's just less fiddly to have a flat surface to solder to than trying to do it on its side as the socket.

Against that the back of a pot acts as more of a heatsink hence the need for a higher iron temp/heat capacity. But yes I like a good solid connection there. Solution is really an iron with some oomph and preferably temperature controlled.

[BigRedX]

21 hours ago, paul_5 said:

The back of the pot is just a large, conductive surface area to solder too - in theory you could solder ALL of the ground wires together at the output socket, but it's just less fiddly to have a flat surface to solder to than trying to do it on its side as the socket.

 

But the back of the pot in itself is not an essential part of the circuit.

 

And the only additional earth cable should be the one from the bridge. Personally I'd solder this to the closest convenient "proper" solder tag, whether that is the one on the volume pot, tone pot or the output jack. That way you aren't trying the heat up an excessively large area/volume of metal and potentially damaging an electrical component in the process.

[Stub Mandrel]

On 17/03/2022 at 10:24, neepheid said:

+1 for roughing up the casing at the solder point before starting.

 

This, and using a half-decent soldering iron

[rmorris]

2 hours ago, BigRedX said:

 

But the back of the pot in itself is not an essential part of the circuit.

 

And the only additional earth cable should be the one from the bridge. Personally I'd solder this to the closest convenient "proper" solder tag, whether that is the one on the volume pot, tone pot or the output jack. That way you aren't trying the heat up an excessively large area/volume of metal and potentially damaging an electrical component in the process.

 

True it's not an essential part of the circuit. But technically it is not good practice to leave any metal floating so it should be tied to a reference potential eg 0V (ground). In reality though it likely makes no real difference on this application.

Point taken re potential damage but fwiw I've never damaged a pot by soldering to the case. Use a high temp for a short time.