Soldered no different than I have many times before.
Are you saying the vintage AB pots have conductive plastic?
I would think the old ones would be carbon.
What I did do those was cut off the too long shafts.
They both had like 2 inch shafts which I cut off with a Dremel and cut off wheel.
Maybe the vibration did something? Dunno
Something we have discovered over the years is that any dealer that orders a large number of pots can have them custom made.
So they can specify the rotation resistance or torque, whether or not there is grease inside, bushing and shaft length.
There seems to be different appearances with CTS pots.
Nylon, aluminum, or brass shaft.
The ones with the smooth back and the ones with the dimple back where the shaft end protrudes.
Tom,I experienced the same thing with those AB 1meg pots I purchased from the same place. I couldn't turn the volume on my #183 past 9 o'clock without almost blowing the windows out. I kept thinking man is this amp f#%#ing LOUD. Then I put an ohmeter on them and found they were NFG.
I cut them on a drill press, and made sure they didn't overheat.
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.
husky wrote:
Having done many plots on pots the Alphas are usually 2 step (two lines no curve) The CTS are usually 3 ~ 4 and the PEC are 4~5.
You will also find the dead zone at each end varies greatly, but is usually 1 number or more
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.
Excellent information.
Are there any true taper pots anywhere? I really dislike the jump and dead zones.
diagrammatiks wrote:weird. I've never had a single problem on the old a/b/clarostat/ohmite etc pots I've used.
I cut shafts down with a dremel all the time.
did you guys get yours from apex?
I got mine from Apex. they are 1W AB Type J
I just measured both of them. Wiper to ground they both do the same thing. They start at @ 3.8k (supposed to be around 0 ohms) reach 1.02 meg at 12 o'clock and reach 1.3 meg fully rotated.
ToneMerc wrote: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
husky wrote:
Having done many plots on pots the Alphas are usually 2 step (two lines no curve) The CTS are usually 3 ~ 4 and the PEC are 4~5.
You will also find the dead zone at each end varies greatly, but is usually 1 number or more
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.
Excellent information.
Are there any true taper pots anywhere? I really dislike the jump and dead zones.
Well the PEC have the most true of a curve I have measured. As far as the dead zone at each end you can specify that when custom ordering. The Bourns are much better than most but also have that two line curve.
Wow, such perfect timing! I'm actually getting ready to build my first amp and was looking at which pots to purchase- could be confusing. I'm looking at Precision Electric right now. A little pricy but should work fine. Any feed back would be great! Thanks!
