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DIY Stompboxes => Building your own stompbox => Topic started by: stratgear on January 14, 2016, 06:28:21 PM

Title: Potentiometer type
Post by: stratgear on January 14, 2016, 06:28:21 PM
Hi all:
I was wondering why no one uses audio sealed pots, in pedals, like these:
https://www.bourns.com/docs/product-datasheets/91_95.pdf  (https://www.bourns.com/docs/product-datasheets/91_95.pdf)

Is it only a budget matter?

I never saw a pedal with other pots than the usual carbon "Alpha" type ones. Whyyyyyyyyy?  :icon_question:

Thank you
Title: Re: Potentiometer type
Post by: davent on January 14, 2016, 07:21:02 PM
Links aren't working for me but... Race to the bottom with regards to price, Tayda r Us.

dave
Title: Re: Potentiometer type
Post by: stallik on January 14, 2016, 07:53:23 PM
I've got a few high quality ones which I think are referred to as wound pots. Trouble is, they're big, have high turn resistance with a 'lumpy' feel and are expensive. The Alphas are smaller, smooth, feel good when turned, are reasonably priced and readily available in most values so I use them in my pedals.
For guitars however, I want a much lower turn resistance so usually use CTS. Perhaps choosing pots on how they feel is wrong but In my case quality is conformance to requirements. Occasionally I want a very high turn resistance to prevent accidental adjustment. In these cases I pop a small o ring under the knob in contact with the case. That changes the feel totally.

Oh and links don't work for me either
Title: Re: Potentiometer type
Post by: stratgear on January 14, 2016, 08:02:22 PM
Thanks, so far.

Link fixed to: https://www.bourns.com/docs/product-datasheets/91_95.pdf (https://www.bourns.com/docs/product-datasheets/91_95.pdf)
Title: Re: Potentiometer type
Post by: ElectricDruid on January 15, 2016, 06:41:57 AM
Quote from: stratgear on January 14, 2016, 06:28:21 PM
Hi all:
I was wondering why no one uses audio sealed pots, in pedals, like these:
https://www.bourns.com/docs/product-datasheets/91_95.pdf  (https://www.bourns.com/docs/product-datasheets/91_95.pdf)

Is it only a budget matter?

I never saw a pedal with other pots than the usual carbon "Alpha" type ones. Whyyyyyyyyy?  :icon_question:

Yes, largely a budget matter. RS Electronics (as an example) list Bourns sealed pots at £5.57 for cermet and £9+ for conductive plastic. That's at least 4 times what you'd pay for a basic alpha pot.

If you put conductive plastic pots on a four-knob pedal, you'd be looking at £40 before you paid for the enclosure, the jacks, the PCB, or the rest of the stuff. Oftentimes you can put a whole pedal together for that kind of money.

If you're feeling flush and want a luxury pedal, go for it. The Bourns pots are good quality, last a long while and won't let beer in. Maybe they're worth it. Some of the top-end modular synth manufacturers use them for longevity.

HTH,
Tom

Title: Re: Potentiometer type
Post by: samhay on January 15, 2016, 07:29:34 AM
I like Bourns GTR pots for guitar/bass duties - have never been able to justify the price of the sealed pots.
The size would make them impractical for many pedal builds.

http://www.farnell.com/datasheets/1771756.pdf
Title: Re: Potentiometer type
Post by: slacker on January 15, 2016, 11:54:18 AM
What's the point of using sealed pots in a pedal? Or is this more about overall quality rather than the fact they're sealed.
Title: Re: Potentiometer type
Post by: stratgear on January 15, 2016, 07:37:44 PM
Quote from: slacker on January 15, 2016, 11:54:18 AM
What's the point of using sealed pots in a pedal? Or is this more about overall quality rather than the fact they're sealed.
What's the point on using sealed pots in an amp or preamp that won't be exposed to such an heavy use and environment as a pedal usually does?...I'm still curious... :icon_confused:
Title: Re: Potentiometer type
Post by: slacker on January 16, 2016, 06:40:33 AM
I don't know, hopefully someone can help us out.
If you look just at the fact they're sealed, the ones you provided a link to are only IP40 rated, so they don't keep out dust or beer, so in a pedal I don't see any advantage over standard pots. https://en.wikipedia.org/wiki/IP_Code (https://en.wikipedia.org/wiki/IP_Code) They do make IP67 rated ones but I dread to think how much they cost.

The other specs don't seem significantly better than standard Alpha or other similar quality pots.