Trimpot and IC socket question

olledahlberg · Joined: Nov 28, 2012 Posts: 23 Location: sweden

I have trimpots which I intend to install on my Ultimate PC board. I just wonder if they will work if i install them in either way? The middle lead is called "2" on my pots

Here is the pot:
http://www.electrokit.com/trimpot-3266w-100-kohm.41562

I also wonder how important it is to have gold plated IC-sockets. They are maby 5 times the price of non-gold plated ones

-minus- · Joined: Oct 26, 2008 Posts: 781 Audio files: 13

I have not checked the schematic to be 100% sure, but the trim pot would work whichever way you soldered it. You could hook it up to a LED and see what happens when you turn the pot clockwise. I always get pots the wrong way around... and my toast falls buttered side down. Laughing

With the IC sockets non-gold ones will work fine. Or no sockets even, except you will have a difficult job removing them if something goes wrong. I have both types of socket here but actually prefer the cheaper ones as I can bent two legs in opposite diagonal corners to hold the IC socket in place when I solder them.

ashleym · Joined: Aug 20, 2009 Posts: 181 Location: uk

Good advice above.

Do put in all the trimmers the same way round or you will drive yourself mad twisting one way and another. My preference is for things (pitch, frequency) to go up when I turn clockwise. I know I put one in the opposite way round to the others................ Embarassed

For sockets dont worry about gold plated. I prefer the contact quality of turned sockets- these are the ones with round holes in

http://www.rapidonline.com/Cables-Connectors/Low-Profile-Turned-Pin-DIL-sockets-63764

but because the contact is so firm you can end up bending the legs of the IC pins. So these can work very well too

http://www.rapidonline.com/Cables-Connectors/DIL-IC-Sockets-400861

They are a lot cheaper, s get yourself a tube of them and you wont have to worry about running out.

Please keep us updated with your build?

fluxmonkey · Joined: Jun 24, 2005 Posts: 707 Location: cleve

ray's layout is for trimpots w/ the leads all in a row... the 3266 series you linked to would work electrically, but the leads won't line up perfectly. better to go with the 3296 series, like:
http://www.electrokit.com/trimpot-3296w-500kohm-25-varv.46182

orientation does not matter, center lead is always the wiper, the resistor element itself does not have a a direction.

goldplate contacts seem like overkill, just go w/ regular machined pins.

b

Uncle Krunkus · Posted: Tue Dec 25, 2012 1:27 am Post subject:

Yeah,
I wouldn't worry too much about trimpots being backward. The difference is that on a multiturn, clockwise will be freq, offset, shape, etc going up, and the other way the same effect will be anticlockwise. I do agree with ashleym, in as much that on a nice build, you preferably want the trimming action to "make sense", if you can orient them that way easily. Then again, when it comes to "sine shape" which way is "up"? And once you've set these trimmers, how long will it be before you need to set them again?
It's a lot more important IMHO to get the panel pots the right way round, (which can sometimes be a headache) but when they're wrong they'll drive you nuts, so they will literally fix themselves. Laughing

olledahlberg · Joined: Nov 28, 2012 Posts: 23 Location: sweden

Thanks a lot for the response! Im still waiting for some components to arrive, meanwhile Im thinking about the cabinets. (Planning to build an Ultimate expander as well). My father in law is working a lot with polycarbonate and safety glass, so Ill build transperent cabinets for the synth and expander from scrap pieces of poly glass. Ill probably make one cabinet for each device.

ashleym · Joined: Aug 20, 2009 Posts: 181 Location: uk

I put both into one cabinet. (The cabinet has been finished for a while but I have only now had the time to mate the two. Not the best fit but I have zero woodworking skills so any result is good. I was cutting and drilling today to make some speakers and if I can make a square box anyone can!!). I would think twice about transparent cabinets because they will look very busy with all the panel components and wiring. I think this will hinder easy "reading" of a patch etc- just my opinion and SDIY is about getting what you want so ignore me if you want Cool

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olledahlberg · Joined: Nov 28, 2012 Posts: 23 Location: sweden

That one piece of nice front panel! I think its ok to build a transperent case since my front panels will be aluminium (bought the ultimate from Ray and making the expander panel my self).

ashleym · Joined: Aug 20, 2009 Posts: 181 Location: uk

Thanks for that.

I have made up 2 panels. They are just mounted in the same box. One as the regular Ultimate and the bottom as an expanded Expander. I have an MFOS sequencer made to the same panel size and when that is up and running I will post some more pictures.