Trimpot types and their relative benefits?

[mordechai]

I've been using the el-cheapo Tayda trimmers for a few years.  I like them fine for the most part, but I am doing a few Tonebender (MK II) fuzz builds right now and would like to hear recommendations for trimmers that might have better noise specs and tolerances for a higher quality build.  Please chime in with your thoughts and preferences for trimmers that would be, in your view, best suited for these builds (they will be going on the collectors of Q2 mostly). 

Thanks!

[Kevin Mitchell]

I can imagine the only variable for trimmers is the tolerance and how they hold up physically. Trimmer types are only specified to fit the build design and not the circuit design.

Tayda stocks a few different types which are common clones of big names for what is typically used around here
-The 25 turn ones are great for circuits that require fine tuning (the hard to dial sweet spots)
-The 3362 clones are good for physical stability since they mount flush to the board and also have a low profile.
-The 6mm ones are good because you can access them from the trace side of the board with a small slot screwdriver - given there's holes to do so.

Allot of folks seem to like piher brand trimmers - or at least used to (you might see the black and white trimpots on some builds). I rarely look for these as the alternatives are just as good, less expensive and more readily available.

Don't over think trimpots. Use what works best for you and your project 

[Mark Hammer]

My own experience is that the wider the diameter, the better the wiper quality and the more precise the pot and repeatable the setting.  So trimmers, having particularly small diameters, don't have especially great wipers or precision.  Ten-turn units improve upon that.

One of the traits not mentioned is the ability to mount the trimmer on the board and still be able to adjust it through a hole in the PCB.  IN that respect, as precise as 10-turn units are, you can't adjust them from the back of the board.  Of course, given their greater precision, maybe once they've been adjusted with the board out of the chassis, there is no further need to tweak from the copper side of the board.

[Kevin Mitchell]

-The 6mm ones are good because you can access them from the trace side of the board with a small slot screwdriver - given there's holes to do so.

One of the traits not mentioned is the ability to mount the trimmer on the board and still be able to adjust it through a hole in the PCB.

[Mark Hammer]

 

[duck_arse]

ten/fifteen turn pots come in all many of shapes [square or rectangle], for flush or upright mount, and adjusters can be top or side, giving quite a variety of 'solutions'.

any of the enclosed trimpots, IME, is more mechanically reliable, less prone to falling apart, than the open backed ones [like those popular blue ones].

[duck_arse]

now with pictures! IF you use a trimpot set once and seal/forget, the type matters less than if, like me, you often use them for back and forth on the breadboard. so, in my opinion/experience, this:

the skeleton type - I've never liked, refused to use.

these are better, but can sometimes be loose and tight in a single turn. there is no protection for the 'rotor handle'.

these are similar again, with the open under, but has a protected adjuster.

these pihers - erm, who has a screwdriver/adjuster that small/shape to hand when needed? I've always avoided these.

and
these two styles are good, they are "sealed" and generally of a decent quality.

these are all single turn type, first pics I could find. other people might suggest other styles for other reasons.

10 turns trimpots are usually good quality to start with.

[bean]

3362p all day long, every day. You can get them at Mouser too. Also, there is a version of the 3362 which has a little knob instead of requiring a tool.

https://www.mouser.com/ProductDetail/Bourns/3362P-1-104TLF?qs=sGAEpiMZZMvygUB3GLcD7tPv2CTgdw57bg5H%2fN8ZZVM%3d

[GGBB]

The improved precision of multi turn trimmers is useful for dialing in bias accurately, but some (most?) multi turn trimmers are identical in quality to their single turn counterparts. The multi turn is just a mechanical add on. Helpful, but not necessarily an indicator of higher quality.