# Using trimmers in place of pots



## Danbieranowski (Sep 7, 2021)

I like to do this from time to time if I'm doing a combo build and I want to hide some of the controls internally. Has anyone come up with a clever way of fitting the trimmer to the spaced 16mm PCB mount pot holes that isn't just putting a wire out to the 3 legs? I'm looking for something a little more professional or secure looking than that if anyone is aware of an adapter board or anything.


----------



## Matmosphere (Sep 7, 2021)

You could do it with a piece of perfboard or veroboard.

It would be pretty straightforward to make one in eagle and get them made up


----------



## phi1 (Sep 7, 2021)

I’ve done it a few times with vero (stripboard) as suggested above. This is nice but a pcb would be easier and look neater, maybe pedalpcb could be persuaded to make one.


----------



## Danbieranowski (Sep 7, 2021)

Matmosphere said:


> You could do it with a piece of perfboard or veroboard.
> 
> It would be pretty straightforward to make one in eagle and get them made up


I’ve considered it for sure, I’m just happy to pay for them if someone else makes them or has any ideas.


----------



## manfesto (Sep 7, 2021)

@PedalPCB this would actually be a really handy utility adapter board, the TrimmitXL?


----------



## Danbieranowski (Sep 7, 2021)

I figure a couple header pins will stand it off the PCB as well.


----------



## phi1 (Sep 7, 2021)

Exactly. One issue with vero is you can only solder to one side, making it tricky to use with header pins. The enclosed square type of trimmer is problematic… which side do you put the copper strips since the plastic of the header pins sit flush to the bottom, and the square box of the trimmer sits flush to the top. I’ve had better success using the ‘circle standing on three legs’ type of trimmer, since you can put the copper on the top and solder the exposed trimmer legs to the top.

a pcb would solve all of that and look very classy.


----------



## K Pedals (Sep 7, 2021)

Has anyone tried using this kind??









						5K OHM TRIMMER POTENTIOMETER CERMET 25 TURNS 3296W
					

Lead Free - Get It Fast - Same Day Shipping




					www.taydaelectronics.com


----------



## almondcity (Sep 7, 2021)

I used those once, they worked well


----------



## K Pedals (Sep 7, 2021)

almondcity said:


> I used those once, they worked well


I mean in place of a regular pot?


----------



## Danbieranowski (Sep 7, 2021)

almondcity said:


> I used those once, they worked well


Did you just bend the legs out to hit the spacing of the pads for PCB-mount pots?


----------



## Danbieranowski (Sep 7, 2021)

K Pedals said:


> Has anyone tried using this kind??
> 
> 
> 
> ...


Seems promising as long as the legs can reach the pot spacing!


----------



## almondcity (Sep 7, 2021)

Yes I bent the legs, they reach


----------



## almondcity (Sep 7, 2021)

K Pedals said:


> I mean in place of a regular pot?


Yep


----------



## Danbieranowski (Sep 7, 2021)

almondcity said:


> Yes I bent the legs, they reach


Shit that’s great. Are they short enough to not hit the enclosure along side regular PCB mount pots or did you have to bend em sideways?


----------



## almondcity (Sep 7, 2021)

That's a good question. I didn't have pcb mounted pots on my build. I had a 1590BB enclosure and I think it would be close. Should be OK for a 125B height, they're about the size of some electrolytic caps


----------



## Feral Feline (Sep 8, 2021)

I've also used the multi-turn cermet trimmers as per AlmondCity, in a 1590BB. Don't recall having to lay 'm down.

As noted, they're about the size of a box film-cap. They should fit.


----------



## Danbieranowski (Sep 8, 2021)

@almondcity @Feral Feline I've never seen one in person before so this is super helpful. On another note, does multi-turn mean they are more 'dial-in-able' than the standard trimmers we are used to that have about as much turn as a normal pot?


----------



## Feral Feline (Sep 8, 2021)

Danbieranowski said:


> @almondcity @Feral Feline I've never seen one in person before so this is super helpful. On another note, does multi-turn mean they are more 'dial-in-able' than the standard trimmers we are used to that have about as much turn as a normal pot?


Absolutely!

As you've noted, the "normal" trimmers are just like a regular pot in terms of their amount of rotation they go from 7 o'clock to 5 o'clock; however, because of their smaller size than a regular pot with knob, they're much harder to give a subtle tweak to. If you're having trouble dialing in a knob on a build, try a bigger knob if you have room. For the trimmers, use the fattest screwdriver handle you can find and that will help slow down the turning ratio and make it a little easier to dial in the cursed things.

The first time I used a multi-turn cermet, I didn't realise it had such a huge range of adjustment. So the SHO I built for a friend (in a 1590A, and the cermet fit, to give you some size-indication) was modded to have the trimmer on the gain with a master volume — dial in the sweet spot and then let as much or little signal through as needed. I built it the night before my plane left to visit him with no time to test it other than it was passing signal in both bypass and engaged. In his practice space, it was woefully disappointing — hardly any boost at all to begin with and not much better after tweaking. So I left with my tail between my legs and did the homework I should've done from the get go — tip: read the datasheets on all your new-to-you components BEFORE you build your circuit. So I returned with the newfound knowledge that we could really crank this cermet — the boom was back!

I think these multi-turn things are great for chorus, flangers, univibes — anything known to be notoriously tricky-dicky to dial in the sweet spot.


----------



## JamieJ (Sep 8, 2021)

This is a great idea - there are a lot of circuits that I just set and forget the tone control. I will definitely give this a try.


----------



## mdc (Sep 8, 2021)

I've found those multi-turn cermets to be kind of fragile, but maybe I just bought cheap ones? It's easy to dial them past the stop on either end and break them.


----------



## Feral Feline (Sep 8, 2021)

I've had no such problems with the Bourns I used.


----------



## bowanderror (Oct 11, 2021)

mdc said:


> I've found those multi-turn cermets to be kind of fragile, but maybe I just bought cheap ones? It's easy to dial them past the stop on either end and break them.


Oh shit, can you break them by doing that? I have defo gone past the click a fair few times.

Lately I've been using a DMM to set multiturn trimmers to the middle of their resistance before installing them. Knowing the starting point definitely makes dialing them in a LOT easier.


----------



## finebyfine (Oct 11, 2021)

I have little adapter boards that map three footprints to eachother: 3362 trimpots, 9mm potentiometers and 16mm potentiometers. 9mm and 16mm pots will lineup hole locations. https://easyeda.com/editor#id=146b023547944d7585f292f524ba5fe7

I forget how many of these I have made and on hand if any - I don't use them often - but happy to mail some out to anyone if I have some.


----------



## Danbieranowski (Oct 11, 2021)

finebyfine said:


> I have little adapter boards that map three footprints to eachother: 3362 trimpots, 9mm potentiometers and 16mm potentiometers. 9mm and 16mm pots will lineup hole locations. https://easyeda.com/editor#id=146b023547944d7585f292f524ba5fe7
> 
> I forget how many of these I have made and on hand if any - I don't use them often - but happy to mail some out to anyone if I have some.


That's exactly what I was hoping for! Happy to pay you for a handful if you have them.


----------



## fig (Oct 11, 2021)

bowanderror said:


> Oh shit, can you break them by doing that? I have defo gone past the click a fair few times.
> 
> Lately I've been using a DMM to set multiturn trimmers to the middle of their resistance before installing them. Knowing the starting point definitely makes dialing them in a LOT easier.


Same here, though I rarely use them any unless fine-tuning is apparently crucial like measuring for a bias resistor. Incidentally, I learned that on this forum.


----------



## daeg (Oct 11, 2021)

Danbieranowski said:


> Seems promising as long as the legs can reach the pot spacing!


I've done this before and I didn't like the way it turned out. The legs had to be bend so much that it wasn't even close to flush with the board and the whole thing could be bent over with a slight push.


----------



## Danbieranowski (Oct 12, 2021)

daeg said:


> I've done this before and I didn't like the way it turned out. The legs had to be bend so much that it wasn't even close to flush with the board and the whole thing could be bent over with a slight push.


Same here. It's definitely not an ideal solution.


----------

