cts pots consistency

[grazioso]

anybody lately noticed that cts pots got very inconsistent or do i have just bad batch...?

i got 10 500k cts audio pots and i can't find even two of them that have similar ramp up, some of them act outright linear even though they are stamped audio on the casing...

this is my main 6 string humbucking guitar that had worn out and noisy old ceterlab pots and no cleaning could helped it, so i finally decided to change them all together, the pickups are identical, the caps are identical and pots are "same value and taper" and so the outcome should be at least similar but it is not...i can't stand the situation that i roll off volume on neck pickup and it takes almost full turn to work a bit - i tried all of them one by one and various combinations, i hooked up those pots to my fluke multimeter and choose those that were the closest in values and the outcome is still pretty bad, i tried new caps with close tolerance too, i rewired the whole thing several times, i made sure there is no poor connection, no underheated solder... but it still sucks...so out of desperation i put in four new cts 250k audio pots and they are much more consistent but are just too low of a value for humbucking so i concluded that those 500k pots that i got are simply bad and inconsistent....SO:

are those expensive pots from MEC any better? i know gotoh makes some pots too and i have tried their 250k in my strat clone and it was ok but i haven't tried their 500k pots yet (and i don't see them with solid shaft) ... i am truly frustrated with this situation since i use a lot volume roll off approach to clean the sound from my 18 watt amp and vice versa ... so any hint is greatly appreciated .... i'd like to sort this problem out for good no matter what the cost is ....

[aceonbass]

Check out NTE pots. They exceed military specs and are around $12@.

[johnhall]

Obviously you're not speaking about pots purchased from us.

CTS isn't any different than anyone else in that they make pots in all different styles and grades. The "tightness" of the spec, just as in resistors or capacitors, is a spec in itself and greatly affects the pricing, i.e. tight spec pots are going to cost more.

The ones we use are custom-made and most of the parameters you mention are part of the specification. Obviously we try to find a balance between performance and cost, but I guarantee you that they are made to a higher standard of tolerance than general purpose, over-the-counter goods.

Bourns is one of the few makers that have targeted the guitar market with specialty pots and you'll find the consistency and repeatability of these are probably as good as those we use from CTS but at a price.

http://www.mouser.com/bournsproaudio/#tabs-6

[Wiker]

Took some quick measures of a few 500K pots:
Original tone pot from ’79 4001: 460K full up, 130K turned 90° down, 30K turned 180° down.
New 500K CTS tone pot from Fender: 442K full up, 130K at 90°, 32K at 180°.
New 500K CTS audio pot from AllParts: 496K full up, 190K at 90°, 38K at 180°.
And a 500K MEC log pot: 428K full up, 197K at 90°, 36K at 180°.

[grazioso]

Obviously you're not speaking about pots purchased from us.

CTS isn't any different than anyone else in that they make pots in all different styles and grades. The "tightness" of the spec, just as in resistors or capacitors, is a spec in itself and greatly affects the pricing, i.e. tight spec pots are going to cost more.

The ones we use are custom-made and most of the parameters you mention are part of the specification. Obviously we try to find a balance between performance and cost, but I guarantee you that they are made to a higher standard of tolerance than general purpose, over-the-counter goods.

Bourns is one of the few makers that have targeted the guitar market with specialty pots and you'll find the consistency and repeatability of these are probably as good as those we use from CTS but at a price.

http://www.mouser.com/bournsproaudio/#tabs-6

no they were not from rickenbacker since you don't ship here, they came from guitarpartsresource.com but i thank you very much for the link. i'll order some bourns pots to give it a shot, right now i ended up having two closest matching cts log at volume controls and a pair of ancient 60's sealed czech tesla military specs linear pots for tone controls. it is ok for now, but with the next change of strings it will get redone again...

[grazioso]

Took some quick measures of a few 500K pots:
Original tone pot from ’79 4001: 460K full up, 130K turned 90° down, 30K turned 180° down.
New 500K CTS tone pot from Fender: 442K full up, 130K at 90°, 32K at 180°.
New 500K CTS audio pot from AllParts: 496K full up, 190K at 90°, 38K at 180°.
And a 500K MEC log pot: 428K full up, 197K at 90°, 36K at 180°.

hm so i will take my multimeter to the store with me and will ttest their batch of 500k MECs too...i can imagine how happy they will be to see me like that there

[cjj]

CTS pots are generally available in tolerance ratings of 30%, 20%, and 10%. So, in the best "standard" grade, 10%, full up on a 500k could be as low as 450k or as high as 550k. 20% would be 400k to 600k. Of course, when measuring them, you also have to take into account the precision/calibration of your ohm meter too.

[Wiker]

If I got it right, what you didn’t like was not that the overall resistance was too far off the rated 500K, but that they tapper off too slowly?

Just to clarify; The CTS pots I measured were different types of CTS pots.
I have two of those from AllParts (which btw look the same as the solid shaft 500K CTS pots at guitarpartsresource, steel shaft and aluminum bussing). Both these two had the same slow tapper off.
I have several of the ones from Fender, and they all have the same faster tapper equal to my original ’79 CTS pots. (These Fender pots have brass shaft and brass bussing.)
Just wanted to say so it was clear you have to find a different kind of CTS pot.

Curious, how did your original pots measure?

[aceonbass]

The Bourns pots look like they may just be the ticket for 250&500K pots. Has anyone here determined which part numbers would apply to use in Ricks? I find their part number charts a bit confusing.

[johnallg]

Took some quick measures of a few 500K pots:
Original tone pot from ’79 4001: 460K full up, 130K turned 90° down, 30K turned 180° down.
New 500K CTS tone pot from Fender: 442K full up, 130K at 90°, 32K at 180°.
New 500K CTS audio pot from AllParts: 496K full up, 190K at 90°, 38K at 180°.
And a 500K MEC log pot: 428K full up, 197K at 90°, 36K at 180°.

hm so i will take my multimeter to the store with me and will ttest their batch of 500k MECs too...i can imagine how happy they will be to see me like that there

[Wiker]

The Bourns pots look like they may just be the ticket for 250&500K pots. Has anyone here determined which part numbers would apply to use in Ricks? I find their part number charts a bit confusing.

Yes, Bourns pots seems nice.
http://www.bourns.com/data/global/pdfs/PDB241-GTR.pdf
PDB241-GTR02-254A2 = plain shaft, 250K, audio taper
PDB241-GTR02-504A2 = plain shaft, 500K, audio taper

[grazioso]

If I got it right, what you didn’t like was not that the overall resistance was too far off the rated 500K, but that they tapper off too slowly?

Just to clarify; The CTS pots I measured were different types of CTS pots.
I have two of those from AllParts (which btw look the same as the solid shaft 500K CTS pots at guitarpartsresource, steel shaft and aluminum bussing). Both these two had the same slow tapper off.
I have several of the ones from Fender, and they all have the same faster tapper equal to my original ’79 CTS pots. (These Fender pots have brass shaft and brass bussing.)
Just wanted to say so it was clear you have to find a different kind of CTS pot.

Curious, how did your original pots measure?

well the originals measured all around 480k-470k full on and i haven't measured the original pots any further since they were worn out a lot. from those cts that i got 2 had tapper that was kinda ok smooth and similar to typical audio pot as i am used to it - with small adjustment down it does make very audible change and the rest was very slow tapper or linear..so those two that i pronounced acceptable are now serving as volume pots...and the rest is serving back in the spare parts box...

[grazioso]

CTS pots are generally available in tolerance ratings of 30%, 20%, and 10%. So, in the best "standard" grade, 10%, full up on a 500k could be as low as 450k or as high as 550k. 20% would be 400k to 600k. Of course, when measuring them, you also have to take into account the precision/calibration of your ohm meter too.

that is horrible, but it would explain the outcome from my batch...if water treatment facility had such tolerances we all would be dead