9mm Alpha Pot Discussion

[rullywowr]

I haven't used many 9mm Alpha Pots yet, however I understand they come in plastic shaft or metal shaft. 

While the plastic shafts are about $1.00 cheaper than the metal, do they hold up in your experiences?  Or would you recommend to just suck it up and get the metal shaft versions?

Thanks!

[croquet hoop]

The plastic shaft version has no threading, and thus can only be mounted on the PCB, with no anchoring point to the enclosure. It can be useful to make an external trimmer, but it is not really an alternative to normal 9mm pots.

[RobA]

I like the little plastic guys for breadboarding. They seem to be fine for using if you are going to board mount your pots and you have the board will secured. There are multiple brands of them, so I'm not sure that it's actually the Alpha pots, but there are several commercial pedals that use the little plastic shaft pots in a mini-pot, knobless setting.

[rullywowr]

The plastic shaft version has no threading, and thus can only be mounted on the PCB, with no anchoring point to the enclosure. It can be useful to make an external trimmer, but it is not really an alternative to normal 9mm pots.

Thanks for the insight, guys...I overlooked the fact that the plastic ones had no threading!  Hmm, that wouldn't attach a board mounted PCB very well to the enclosure now...would it?    

I am going to stock up on some of the 9mm metal guys soon to try and do tighter layouts.  I have a huge supply of 16mm pots which I have been going through, but it would be great to shrink my PCB layouts a little and even get ready for some (gasp!) SMD.

[croquet hoop]

I like the little plastic guys for breadboarding. They seem to be fine for using if you are going to board mount your pots and you have the board will secured. There are multiple brands of them, so I'm not sure that it's actually the Alpha pots, but there are several commercial pedals that use the little plastic shaft pots in a mini-pot, knobless setting.

Yes, that's what Mooer does for instance. All three pots and the switch are mounted to the PCB, but only one pot and the switch are attached to the enclosure, the other two pots (plastic shafts) just emerge from 6 mm holes. I wanted to try something similar, but given the planning needed for the PCB and the enclosure I ended up shelling the extra $2 for normal pots.

Besides, this system can be nice for external trimmers, but it is rather impractical for anything you're going to adjust frequently.

[rullywowr]

Interesting, I guess this does save 2 bucks and makes it slightly easier to assemble, but I'm with you: it's not really worth it. 

I have to assume that the plastic shafts are way more likely to break from a misplaced foot than metal, or from being tossed around in a gig bag, on the floor, etc

[croquet hoop]

They are only 8mm high, so they are protected by the main knob and the toggle switch. I wouldn't be too concerned about them being too fragile.

It may be worth it for lage scale production, but not quite for hobbyists.

[pickdropper]

The plastic ones have their place.  They are nice if you want to use them in an tight space without a knob.  They are designed to stand alone.

As mentioned earlier in the thread, those won't mount to the enclosure, so something else on the board will have to.  A mix of metal pots that mount to the enclosure and plastic pots that don't can be a nice mix.

[jkokura]

I think VFE and Way Huge are two examples I can think of using them, in combo with other PCB mount pots, on finished projects. Take a look at the Way Hugh Pork Loin and anything from VFE really, and you'll see what I mean.

They're using other knobs with pots for main controls, and using those little plastic 9mm pots as 'external trimmers' I think.

Jacob

[rullywowr]

Interesting.  Are the footprints on the PCB identical?  (I'm thinking yes but...)

How about attaching knobs to the plastic guys...any troubles as long as it has a set screw?  Or do you prefer knurled only?

EDIT...I see now....Interesting approach especially on the pork loin.  Could save some space with a control you didn't need to tweak that often.  The drawback is that the little square it occupies on the PCB is pretty much wasted space (not a lot of room to put other components in there).  A bonus is that you don't need to buy any knobs for those controls...I'm intrigued now.

[croquet hoop]

Attaching a knob is definitely doable, but since they portrude by only ~8 mm, most screws will barely catch the top of the shaft and the knob won't feel really secured to the shaft (which is slimmer than metal round shafts). It will work, but it won't feel solid. So it's not a good choice if you want to use them as normal pots. As external trimmers, or less-often used pots, they can be very nice though.

[rullywowr]

Thanks for the information, it's really helpful!

[pickdropper]

Interesting.  Are the footprints on the PCB identical?  (I'm thinking yes but...)

How about attaching knobs to the plastic guys...any troubles as long as it has a set screw?  Or do you prefer knurled only?

EDIT...I see now....Interesting approach especially on the pork loin.  Could save some space with a control you didn't need to tweak that often.  The drawback is that the little square it occupies on the PCB is pretty much wasted space (not a lot of room to put other components in there).  A bonus is that you don't need to buy any knobs for those controls...I'm intrigued now.

Sure you can.  Just put SMT parts on the other side of the board.  Then you won't lose the entire footprint of the pot.

[rullywowr]

Interesting.  Are the footprints on the PCB identical?  (I'm thinking yes but...)

How about attaching knobs to the plastic guys...any troubles as long as it has a set screw?  Or do you prefer knurled only?

EDIT...I see now....Interesting approach especially on the pork loin.  Could save some space with a control you didn't need to tweak that often.  The drawback is that the little square it occupies on the PCB is pretty much wasted space (not a lot of room to put other components in there).  A bonus is that you don't need to buy any knobs for those controls...I'm intrigued now.

Sure you can.  Just put SMT parts on the other side of the board.  Then you won't lose the entire footprint of the pot.

Looking forward to it!  In fact have a huge bunch of 0603 and 0805 components in baggies and today my 200pcs of SMT storage lid containers are due in...Gonna take a while tonight with my labeler but it will be worth it when it's all organized.

[culturejam]

Interesting.  Are the footprints on the PCB identical?  (I'm thinking yes but...)

Yes, the footprint is identical.