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Epi Jack Casady volume pot replacement (again)

#43
Another JC owner here.. same story... original pots from purchase lasted ~5mo, replaced at shop, worked Ok for about 1yr and started to get progressively worse. Been playing mostly upright for the past few yrs to the JC has been in storage until recently and I have a new found NEED to find the solution. As it is both pots & the 3 way selector are garbage... I did try to get the pots w/ DeOx but was rush job before a gig.. I do plan to pop 'em out so I can get in there good and hopefully that will buy me some time...

Most recently I made a number of calls/emails around looking for a solution... nothing really new to add to this thread other than I did get a price quote for all the electronics (sans harness) from the local Guitar Center.
Here's the Gibson p/n's & pricing I was given:
  • vol pot: PPT-202 @ $1.70
  • tone pot: PPT-203 @ $1.70
  • 3 Way: PMS-205 @ 5.00
  • p/u: PPU-219 @ 23.00
  • Transformer: PC01 @ 9.00
Now I find it a little hard to think I could replace all the guts of my bass for ~$40! I still would rather find the quality solution but I may have to stock up on all the parts in case....

Either way, I will be checking back often & adding anything new I find
 
#44
Does anyone know if there's any difference between the volume and tone pots? The schematic says both are 2.5K, but does not mention taper. I'm hoping to effectively combine them onto one concentric pot, but haven't been able to find 2.5K concentrics anywhere - closest I've come is a 10K log concentric pot with a 3.333K resistor in parallel, to bring that 10K max resistance down to 2.5K. Are the tapers different?
 
#45
After being irritated by the crappy pots on my JC for several years, I did a little research. The CTS 450G series of pots are sold specifically for guitars. Unfortunately there is no 2K5 log part. However, if you look at their 450 range, from which the 450G is derived:
[Invalid or Expired Link Removed]

There is very definitely a 2k5 log option. I'm guessing that there is a MOQ to get CTS to build a batch - I mailed them and didn't get a response. I suggested to Gibson that they might like to commission a batch for us JC owners. They thanked me for my suggestion.

In the mean time: There is a solution. If you get stereo 5K pots (which are way easier to find than 2K5) and wire both halves in parallel you get the desired value. I think the fact that you have two separate pots in parallel may also reduce crackle as they wear.
 
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#46
There are places that will make low volumes of custom pot value for not completely unreasonable amounts of money - I've had luck at banzai.de, that's who I had build the stacked concentric 2.5Ks I'm using in my JC project.
 
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#48
As I put in "Pickups & Electronics":

Order a good CTS / Orangedrop combination as for a PB (two 250K's, 0.047muF), remove the 2.5K pots and connect the JC Electar pick-up directly to the rotary switch input. Connect the transformer output to the two new pots as you can find in any PB scheme, then to the output.
Before changing anything, confirm yourself that you can find the right wires in this "old-world telephone exchange"!

Result:
- no cracks anymore!
- the sound is not changed, except for the effect of the tone pot. Depends on the rotary switch position and input impedance of your amplifier or device. But that was also the case before modification (some years ago I posted a question about this, but few JC-bassists seem to use different amps, I guess...).
- no more searching for the right pots, the new ones are regular.
- the JC Bass seems not critical for changing the wiring, the sound is still in your fingers.
 
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#49
Pimpernel Smith said:
lobster11:

You are doing a good service for us Casady bass owners.
I encourage you to keep this diary going until you find the correct pots, and then let us all know where you got them.

Additionally, do you have a link to the schematic of the JC bass?

If so, I'd like to see it and print it and keep it in my bass case, should I need it in the future. I've had my JC bass since 1998, and so far everything works properly - I play it every night.

But, I'd like to have the information for when the time to have it repaired comes.

It really begs the question: Why doesn't Epiphone have these available for quick and easy replacements?
Click to expand...
casady transformer.png
casady transformer.png
 
#51
paulelhierro said:
Here (once again) my change(s) in my JC Bass. The T and V pots are normal cts pots, 250k (NOT 2.5k !) and condensator of 50nF (all as in a normal PB wiring). I recommend this change as I wrote above...
Click to expand...

Yes, that configuration is the one I suggested on the first page of this thread. I never needed to use it since my controls haven't failed but I'm glad to see it worked for you.
 
#55
bholder said:
Does anyone know if there's any difference between the volume and tone pots? The schematic says both are 2.5K, but does not mention taper. I'm hoping to effectively combine them onto one concentric pot, but haven't been able to find 2.5K concentrics anywhere - closest I've come is a 10K log concentric pot with a 3.333K resistor in parallel, to bring that 10K max resistance down to 2.5K. Are the tapers different?
Click to expand...
The new pots that I've received from Gibsophone, both volume and tone are identical.
 
#56
Whelp..... one more time for the world?

unfortunately it appears that a viable drop in replacement has yet to be found...
or at least reported back to this thread... if I've missed something, anything please let me know.

I've just recently moved across the country & I am taking some gear into the shop for some work and figured i would give the old "replace/upgrade the pots on the Casady" another shot. My new local luthier is pretty confident he'll be able to source a solution, I will report back good/bad or indifferent.

Meanwhile someone on a FB forum claims his guy in Oregon found the unicorn, but all he did was pay the guy. I have sent an email to the "guy in Oregon" but not have not heard back yet.

If the redesign of the circuit to allow use of the 250 pots is the most reliable, long lasting fix then I will do it....

but i'm still fighting the good fight or running a fools errand not sure which just yet....
 
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#59
Kbassface said:
so when you say the parts do exist... do mean quality parts are avail thru Gibson or just the OEM availability is better then in that past?
Click to expand...
I'm guessing that the part availability is better. I guess that because even though it took a few calls/reminders over a few months, my Epiphone/Gibson dealer was able to get me the whole electronic kit and caboodle. If I'm interpreting the dealer's comments right, Gibson is not the quickest to ship out single parts. !LIGHTBULB! "ok then will you please order me one of everything?" Boom, parts in a week. maybe Gibson buys the JCB' unique electronics as a bundle......who knows.
 
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#60
tomZbass said:
I'm guessing that the part availability is better. I guess that because even though it took a few calls/reminders over a few months, my Epiphone/Gibson dealer was able to get me the whole electronic kit and caboodle. If I'm interpreting the dealer's comments right, Gibson is not the quickest to ship out single parts. !LIGHTBULB! "ok then will you please order me one of everything?" Boom, parts in a week. maybe Gibson buys the JCB' unique electronics as a bundle......who knows.
Click to expand...
That would make sense, actually. Hmmm, wonder who the closest dealer is? I sure could use a spare set for my projects... ..especially if I could find / order the black pickup!
 
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