Which Potentiometer ?

[essexbasscat]

This may have been done before. However, I can't find the threads.

Been doing some work on guitars and basses these days, both American and Japanese. In many cases, I've needed to replace pots for a variety of reasons.

Along the way, I've discovered that CTS pots have about 24 splines, while Japanese examples have had 18 splines (so far). This makes them non interchangable between U.S + oriental control knobs.
I've also heard (don't know how true this is) that CTS pots were used in early Fenders because they were some of the cheapest available at the time (If this is the case, why did they continue ?)

I've also seen many comments online that the electical values of CTS pots can vary by more than 10 %, leading to people looking for better quality pots. (that said, WD music claim their special CTS pots vary by no more than 9%)

As for the Japanese pots, I've had to use cheap Alpha pots which were described in the ad. as being 'ideal for cheaper instruments'.

So, does anyone know of good quality pots they could recommend;
- For replacements for CTS pots (i.e. 24 spline)
- For replacements for Japanese pots (i.e.18 spline)
- other

Thanks all

EBC

(Edit)
I must admit, when I thought of the title, I was thinking in terms of 'Which' magazine, hoping the thread could be a resource of information of potentiometers. Also, i'm not out to throw rocks at the CTS brand, just representing the discussions I've seen while researching the topic)

Thanks again all

Edited March 2, 2016 by essexbasscat

[icastle]

As it's a potentiometer, being + or - 10% makes no real difference in the big scheme of things.
As they're used for setting an audible difference, you either tweak it up or down until you get the sound you want.

I dare say someone will be along shortly to tell me I'm wrong, but IME you really aren't going to hear a difference from tolerance alone unless you convince yourself you can (which is no more scientific than my assertion that you can't when you think about it... ).

A 'good' pot is all about the mechanics of the thing, the way the 'brush' sits uniformly on the track, the smoothness of the track and how many operations it can handle before it wears out.

When you consider how long CTS have been making pots, and the age of some of them that are still working, that'd make them about as good as you're gonna get.

[rmorris]

[quote name='icastle' timestamp='1456953660' post='2994057']
As it's a potentiometer, being + or - 10% makes no real difference in the big scheme of things.
As they're used for setting an audible difference, you either tweak it up or down until you get the sound you want.

I dare say someone will be along shortly to tell me I'm wrong, but IME you really aren't going to hear a difference from tolerance alone unless you convince yourself you can (which is no more scientific than my assertion that you can't when you think about it... ).

A 'good' pot is all about the mechanics of the thing, the way the 'brush' sits uniformly on the track, the smoothness of the track and how many operations it can handle before it wears out.

When you consider how long CTS have been making pots, and the age of some of them that are still working, that'd make them about as good as you're gonna get.
[/quote]

Good advice - the absolute value of a pot will generally not have a tight tolerance. Don't sweat the difference between 9% and 10% tolerance.
Carbon does wear out with use. For best long life opt for Conductive Plastic (or Cermet) tracks.
It can be a bit difficult to get log or audio taper pots in Conductive Plastic (and possibly not so easy to get the high values you might use on passive Hi-Z pickup)
It's possible to approximate a log(gish) taper with a linear law pot with a resistor from wiper to ground.

[fleabag]

CTS and Alpha seem to be the ones most people go for / have heard of, but you could try Bourns pots. They seem to be great quality. As always, YMMV

[Chienmortbb]

Firstly +1 to conductive plastic and cermet pots. Secondly, commercial pots are +/- 20% and that means a 250k could be between 200-300K and a 500K could be 400-600K. Would that affect the tone? Is the Pope Catholic?

Caps are also 20% tolerance unless otherwise stated do you can see how the electrics of your guitar can mess with your tone.

[Chienmortbb]

I forgot to say that I would go for Bourns, Alps or Omeg. I use the Green Omeg ones where I can although it is hard to get those splined. By the way, not everyone agrees with me ( because that is the way Leo did it) but I hate seeing wire soldered to the body of a pot. They were not designed for that and so the joint cannot be guaranteed. You should use proper shielding.

Edited March 6, 2016 by Chienmortbb

[rmorris]

[quote name='Chienmortbb' timestamp='1457281641' post='2997006']
Caps are also 20% tolerance unless otherwise stated do you can see how the electrics of your guitar can mess with your tone.
[/quote]

Whilst it's usual for electrolytic caps to be +/-20% tolerance other types eg ceramic ; film ; poly are generally available in 10% or 5% or tighter tolerance.

[6v6]

Inside a bass CTS or Alpha are perfectly fine IMO, you could pay more for something slightly more fancy, but then take a look inside your FX pedals and amp - all of the pots there are either equivalent or worse than CTS/Alpha IME.

[Chienmortbb]

[quote name='rmorris' timestamp='1457345452' post='2997474']
Whilst it's usual for electrolytic caps to be +/-20% tolerance other types eg ceramic ; film ; poly are generally available in 10% or 5% or tighter tolerance.
[/quote]You are right but the big guitar builders always cut costs on the electrics. They would go for 20% as I this usually lower priced.

[icastle]

[quote name='Chienmortbb' timestamp='1457390614' post='2998160']
You are right but the big guitar builders always cut costs on the electrics. They would go for 20% as I this usually lower priced.
[/quote]

Except of course that they don't use electrolytics in the bog standard passive circuits we're talking about here.

[rmorris]

[quote name='icastle' timestamp='1457397810' post='2998201']
Except of course that they don't use electrolytics in the bog standard passive circuits we're talking about here.
[/quote]

yes - definitely avoid electrolytics where not necessary.
On non-electrolytics - the costs of 20% vs 10% overlap to a large extent depending on the manufacturer / supplier at any particular time. It's pretty much a commodity market. Rather than the tolerance I'd be more concerned about voltage and temperature stability. The 20% types are generally (though not exclusively) likely to have lower quality dielectrics -- but it means they can get more capacitance into a smaller volume. Things do get expensive (in capacitor terms) if you go for 5% tolerance.
I was really thinking more about people fitting their own capacitors / pots so the component cost is a fraction of what you'd end up paying for the same component fitted to a new bass (although you may have to buy a few of the capacitors as they may not be available singly).
As an example for a 100n Cap' I'd likely go for:

[url="http://cpc.farnell.com/wima/mkp2d031001f00kssd/capacitor-10-100nf-100v-mkp2/dp/CA08109"]http://cpc.farnell.c...mkp2/dp/CA08109[/url]

I know it has pcb type legs which might not be the most convenient but probably worth it for the capacitor characteristics. Glue it to the back of the pot and solder / wire wrap !

Edited March 8, 2016 by rmorris

[Chienmortbb]

[quote name='icastle' timestamp='1457397810' post='2998201']
Except of course that they don't use electrolytics in the bog standard passive circuits we're talking about here.
[/quote]I was not talking about electrolytic capacitors. Ceramic are rarely lower than 20%, Film caps are available from 20% down to 2%. However if you are mass producing and buying in the 1000s, even 5p is worth saving. Save 5p on each cap and pot and that can be 20-30p. On a run of 1000 basses that is £200-300.

Edited March 8, 2016 by Chienmortbb

[Chienmortbb]

[quote name='rmorris' timestamp='1457432653' post='2998397']
yes - definitely avoid electrolytics where not necessary.
On non-electrolytics - the costs of 20% vs 10% overlap to a large extent depending on the manufacturer / supplier at any particular time. It's pretty much a commodity market. Rather than the tolerance I'd be more concerned about voltage and temperature stability. The 20% types are generally (though not exclusively) likely to have lower quality dielectrics -- but it means they can get more capacitance into a smaller volume. Things do get expensive (in capacitor terms) if you go for 5% tolerance.
I was really thinking more about people fitting their own capacitors / pots so the component cost is a fraction of what you'd end up paying for the same component fitted to a new bass (although you may have to buy a few of the capacitors as they may not be available singly).
As an example for a 100n Cap' I'd likely go for:

[url="http://cpc.farnell.com/wima/mkp2d031001f00kssd/capacitor-10-100nf-100v-mkp2/dp/CA08109"]http://cpc.farnell.c...mkp2/dp/CA08109[/url]

I know it has pcb type legs which might not be the most convenient but probably worth it for the capacitor characteristics. Glue it to the back of the pot and solder / wire wrap !
[/quote]You are right, that cap you quote is a Wima and an excellent cap. It will be more expensive than some maker's 5% caps as Wima have achieved mythical status in audiophile circles.

[Chienmortbb]

[quote name='6v6' timestamp='1457353517' post='2997578']
Inside a bass CTS or Alpha are perfectly fine IMO, you could pay more for something slightly more fancy, but then take a look inside your FX pedals and amp - all of the pots there are either equivalent or worse than CTS/Alpha IME.
[/quote]Not in my amp they ain't. However I am building it.

[rmorris]

[quote name='Chienmortbb' timestamp='1457453438' post='2998741']
You are right, that cap you quote is a Wima and an excellent cap. It will be more expensive than some maker's 5% caps as Wima have achieved mythical status in audiophile circles.
[/quote]

Yes - it's a Polypropylene dielectric which is excellent in terms of stability over temperature (and likely time) and together with its relatively high 100V dc rating implies that voltage coefficient (giving rise to distortion) should be low (I haven't measured it)
I tend to use these type in my (non audio) work where quality caps are important.
I pointed to CPC as it's available to everyone whereas RS/Farnell etc can be trickier for individuals.

Alternatively...forget about a tone control on the bass itself and use your pedal/preamp etc instead !