Noob question on potentiometers. What type and where to find them?

[ryugu]

Hello

I'm new to pedal building but I'm not new to electronics. I've done several mods. I decided on my first two pedals - Mahayana and Awful Waffle. It's not clear to me yet what style of pots I should be using b/c all I see is values on the parts lists. I read somewhere that the PCB mount type used are 16mm. Do they come in different sizes? Will I be able to get them from Digikey, Mouser, or Parts Express? If not, who sells them? Also what is a "C10K"?

 

[fig]

Most are PCB mount 16mm standard pot. Most any supplier stocks them. A C10K is a reverse log taper.

 

[fig]

Example:

16mm Potentiometer - Short PCB Leg

Top Quality Parts for Guitar Effects Pedals and DIY Music Devices. Knobs, Pots, Switches, Kits, LEDs, Enclosures, Jacks, Wire, Resistors, Capacitors, Semiconductors

stompboxparts.com

 

[Nic]

A = Linear taper Log taper (audio taper)
B = Log taper (audio taper) Linear taper
C = Reverse log taper

As for the legs, those shown by fig are perfect fit for pedal building. Pay attention on the leg length, some have longer legs.
Depending on your choice of knob, you should also be sure you get the right shaft (split, splined, D, 6.35mm, 6mm) A 6.35 knob will not align well on 6mm shaft, more if only one pot has the wrong size... ask me how I know.

And get dust covers, those will keep your pots from shorting on the board.

 

[ryugu]

Huge thanks.

 

[ryugu]

Hey, I got another completely unrelated question regarding small capacitors. What type(s) do you prefer to use? In what cases should tantalum and silver mica caps be used? Do they really sound different?

 

[kweefthief]

becareful when ordering the pots! look at the pictures and make sure the pins are the same type... i just ran into this little problem.

 

[Nic]

becareful when ordering the pots! look at the pictures and make sure the pins are the same type... i just ran into this little problem.

Exactly what I tried to explain in my answer above I also saw your post !

Careful with dual gang also

 

[MichaelW]

Hey, I got another completely unrelated question regarding small capacitors. What type(s) do you prefer to use? In what cases should tantalum and silver mica caps be used? Do they really sound different?

As a GENERAL RULE OF THUMB anything in the picofarad range (pf) use Ceramic/or Multi-layer-ceramic (MLCC). If you're just starting out, get a "kit" of MLCC's off Amazon with various values, it still saves my butt from time to time when I need a value.
Anything in the Nanafarad range (NF) use box type film capacitors. Anything in the UF range use electrolytic or tantalums (there are exceptions, 1uf Film is a common component for instance as is 1uf Electrolytic). The board itself will tell you. the Round looking pads with the polarity signs are for electrolytic. The Square pads are meant for Box Film caps.

Tantalum caps can be uses really in place of any where an electrolytic cap is called for. Whether or not it sounds better is open to (often lengthy debates. They can also be used in place of Box FIlm but since tants have polarity you'll need to understand the circuit enough to know what direction the signal flow is. Thus reading the schematic.

Benefits of tantalum over electrolytic for ME is primarily the size, they are smaller and shorts and work well when I try to squeeze a board meant for a 125B into a 1590B.

 

[ryugu]

As a GENERAL RULE OF THUMB anything in the picofarad range (pf) use Ceramic/or Multi-layer-ceramic (MLCC).

Thanks. What about silver mica or mylar? I'm seeing these on Amazon as well. Any sound difference at all?

 

[scheffehcs]

Quick correction

A = Linear taper
B = Log taper (audio taper)
C = Reverse log taper

A = Log / Audio
B = Linear
C = Reverse Log

According to Wikipedia, pots made in Europe are different, but these are the letter codes for pots made in the USA and Asia.

 

[Barry]

Quick correction

A = Log / Audio
B = Linear
C = Reverse Log

According to Wikipedia, pots made in Europe are different, but these are the letter codes for pots made in the USA and Asia.

There is also a W

 

[MichaelW]

Thanks. What about silver mica or mylar? I'm seeing these on Amazon as well. Any sound difference at all?

Silver mica CAN make a difference if it's in the signal path but it kind fo falls into the "Mojo parts' realms, some people swear by them, others can't hear any difference. They'r expensive and typically only in the PF ranges. For that I'd just use ceramic or MLCC.

 

[Nic]

Quick correction

A = Log / Audio
B = Linear
C = Reverse Log

According to Wikipedia, pots made in Europe are different, but these are the letter codes for pots made in the USA and Asia.

Swoooosh. I was almost certain A was Audio (memory trick), and was no more sure if audio was the log or taper one, so I reserached them and totally screwed up writing those down .

I'll edit my reply just to cause no more confusion.

There is also a W

I knew there were other, but what is a W pot exactly ?

 

[Barry]

Swoooosh. I was almost certain A was Audio (memory trick), and was no more sure if audio was the log or taper one, so I reserached them and totally screwed up writing those down .

I'll edit my reply just to cause no more confusion.


I knew there were other, but what is a W pot exactly ?

W Taper​

The W taper is sometimes referred to as the antilog taper because it related to the exponential function. Its specific functional form of the potentiometer resistance between terminals 1 and 2 is dictated by the following definition.

The “W” taper attains 20% resistance value at 50% of
clockwise rotation (left-hand).

I should mention that you rarely see the W taper described in terms of an actual function – it resistance versus wiper position is almost always shown as a graph. Remember that these are physical parts and they vary quite a bit from their nominal specifications