What a difference a pot makes

[Phil_S]

Hmmm what's common, both of you guys cut the shafts down. I will see if I can find it, but somewhere I have some documentation from PEC stating do not cut the shaft as it will destroy the pot.
TM

We grind them all the time on 80 grit belt sander (a big one) they dont get hot and there is no stress, those are the issues to avoid

It is simple to cut them with a hacksaw and file them smooth. No real heat from that either, for those who don't have a "big" belt sander.

[leadfootdriver]

What does the VR(1-5) mean on the pots layout?

[Structo]

Not talking tolerance here which is usually 20% !!!
Most of the CTS are 10% audio taper and the Alphas usually 15% or 20%
The PEC are usually 10% and yes that makes a big difference. Any time I have tried a Alpha that is 10% audio combined with the cheating "curve" they don't sound right at all.

PS Nylon shaft CTS are no longer available.

Hmm, AES still has the nylon CTS.
Perhaps it is just old inventory?
http://www.tubesandmore.com/scripts/fox ... tem=R-VC-A

What brand pot do you like to use John?
Of course a company such as yours probably orders custom spec pots.

It's strange that such a key component to our audio amps such as potentiometers, can be difficult to source good quality ones with the proper taper.

I have tried the PEC pots before and just couldn't justify the cost.
Although I love the short slotted shaft locking pots for bias adjustment.

Interesting topic.

[Structo]

I was just looking around Mouser at their Bourns offerings.

They carry two different non sealed type pots.
One that has a higher rotational torque for amps and sound equipment.
http://www.mouser.com/ProductDetail/Bou ... bYqw%3d%3d

And one for guitars with a lower rotational torque.
These are probably the same ones that AES has because they turn very easy with almost no torque, which I didn't like but some may.
http://www.mouser.com/ProductDetail/Bou ... Tj7g%3d%3d

Both of these claim 10% taper, carbon element.
http://www.mouser.com/catalogviewer.asp ... atalog=644

But of course they don't make a 1Meg audio pot in those series.

Bourns also makes the sealed pots, the model 82 and model 95.
http://www.mouser.com/catalogviewer.asp ... atalog=644

[diagrammatiks]

yup the 82 and 95 are sealed pots in their pro audio line.

I've been meaning to try them but they are the same price as pec's so I haven't gotten around to it yet.

They are considerably smaller though.

bourns also makes a number of pots in their regular line that are sealed.

[husky]

Not talking tolerance here which is usually 20% !!!
Most of the CTS are 10% audio taper and the Alphas usually 15% or 20%
The PEC are usually 10% and yes that makes a big difference. Any time I have tried a Alpha that is 10% audio combined with the cheating "curve" they don't sound right at all.

PS Nylon shaft CTS are no longer available.

Hmm, AES still has the nylon CTS.
Perhaps it is just old inventory?
http://www.tubesandmore.com/scripts/fox ... tem=R-VC-A

What brand pot do you like to use John?
Of course a company such as yours probably orders custom spec pots.

It's strange that such a key component to our audio amps such as potentiometers, can be difficult to source good quality ones with the proper taper.

I have tried the PEC pots before and just couldn't justify the cost.
Although I love the short slotted shaft locking pots for bias adjustment.

Interesting topic.

Well we do use 3/8" Alpha on the Badger (1 PEC) and on the OD series the smaller 16mm pots (which I might like better) but those amps are really designed with those pots used in the complete tweaking process so anything else I try would require more R&D.

I have made a Badger with PEC and it was just different taper, didnt sound different once I matched values and measured the correct rotation to match, I did check it on spectrum analysis and sweep tests. I would have to raise the price if I stuck with them as well.

I am thinking about switching all to CTS and yes they will do anything you want if you order the minimums (Big $). We are using CTS probably on the Jim Kelley amps and I use the PEC military pots on the Handwired series. We are looking at Bourns as well who will custom taper but they use a sticky grease to control the friction, very weird. I do like them better than the Alphas so far. They have less dead zone. These companies will let you spec custom tapers and you pay an upfront cost for that. I've always had a fondness for the taper and useful range of the CTS 10% audios so I'm leaning that way since we use them on the guitars too. I also need the Push Pulls for the Kelley so I'm looking at a $15k order

[husky]

Both of these claim 10% taper, carbon element.
http://www.mouser.com/catalogviewer.asp ... atalog=644

But of course they don't make a 1Meg audio pot in those series.

Bourns also makes the sealed pots, the model 82 and model 95.
http://www.mouser.com/catalogviewer.asp ... atalog=644

For some reason I cant open these pages, are they 10% audio or taper?

[Gaz]

One thing I have to mention about the Bourns PDA24s was the inconsistent torque friction (maybe due to the strange grease method?). I ordered all high torque from Mouser, yet most of the 500kA's seemed much 'looser'.

I contacted Mouser, and since there were no codes to indicate torque, we determined that some "standard" torques got in the high torque bin.

I ended ordering up some more standard torque to match the others (because I actually preferred the feel over the highs I received), and they were much looser than original 500kA's!

Turns out that the original ones I got were in fact the high torque version, but the friction was so inconsistent that i thought they were different!

I'm not going to use them again to avoid the headache, and John's comment about the 'sticky friction goo' makes me wonder what happens to the torque when the pots are cleaned??

[Structo]

Both of these claim 10% taper, carbon element.
http://www.mouser.com/catalogviewer.asp ... atalog=644

But of course they don't make a 1Meg audio pot in those series.

Bourns also makes the sealed pots, the model 82 and model 95.
http://www.mouser.com/catalogviewer.asp ... atalog=644

For some reason I cant open these pages, are they 10% audio or taper?

Those are Silverlight links, it's a windows plugin for the catalog.

I will post the PDF version.

http://www.mouser.com/catalog/catalogUSD/644/771.pdf

http://www.mouser.com/catalog/catalogUSD/644/770.pdf