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btoth76

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Hello.

 

I dug up the entire internet, contacted many companies, but can't find a replacement "Bass" pot for my 1978 Les Paul Recording.

 

It's a linear 2.5K CTS pot (Anything between 2-3 KOhm would be fine). Unfortunately, I can't use anything that is not spot on. The base diameter is important, as well as the shaft size. It is mounted in a crowded compartment with other things soldered on it's base.

 

It's dimensions are:

 

CTS2K2_zpsmvs5zz2v.jpg

 

CTS2K_zps0knunyg6.jpg

 

Please, if anyone has a good source of such parts, (or has one to sell) inform me.

 

Thank You in advance!

 

Bence.

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My buddy works at switchcraft. Was it made there? Do you have a part number?

 

I can ask him to see if they have anything like that there.

 

It was made by CTS. I can't read the part numbers - they are covered with solder. I have no tools to clean it up.

 

But, any high-quality replacement part would be great with the same dimensions.

 

Bence.

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Thanks to Grog, I have the parts catalogue for the guitar. But I guess those are Gibson's internally used P/Ns - not the supplier's.

 

According to the parts list, it's a "70982 Control 2.5K L bass control"

 

1980%20LPR%201_zpsfz3gvxqy.jpg

 

Bence.

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You can always take a resistor and put it in parallel with a pot (across the two tabs parallel with that cap) to change the effective resistance of the assembly to something lower than the pot itself. Like use a 5k pot in parallel with a 5k resistor and it acts like a... one over this, carry the two, divide by that... a 2.5k pot.

 

Or take a 25k pot and use a 2.7k resistor in parallel to get an effective resistance of 2.4 kohm. Or put a 3.3k resistor in parallel with the 25k pot to get an effective resistance of 2.9 kohm.

 

A linear pot with a resistor in parallel will still have a linear taper.

 

Calculator Here

 

[thumbup]

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You can always take a resistor and put it in parallel with a pot (across the two tabs parallel with that cap) to change the effective resistance of the assembly to something lower than the pot itself. Like use a 5k pot in parallel with a 5k resistor and it acts like a... one over this, carry the two, divide by that... a 2.5k pot.

Or take a 25k pot and use a 2.7k resistor in parallel to get an effective resistance of 2.4 kohm. Or put a 3.3k resistor in parallel with the 25k pot to get an effective resistance of 2.9 kohm.

 

b_mathilliteracy.jpg

 

 

rct

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Series 26 rotary pot?

 

Should be able to put together a part number from the Ordering Information section...

 

http://www.ctscorp.com/wp-content/uploads/2015/11/Series-026.pdf

 

Hello C-RAM.

 

I wrote them an e-mail. They said, nothing is in production with the same specs... it's either a mini-pot, or smooth-shaft.

 

These are in the PDF are made with smooth, 6.35mm shafts. I need it with a knurled, 5.9mm.

 

So what I am looking for is either a NOS, or custom-built part.

 

Bence.

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[scared] The parts list really shocks me. They used tantalum capacitors without proper DC voltage and in filters? Either are definitive don'ts. Tantalum capacitors require DC and are apt only in full-range applications as coupling capacitor, not in filters. They distort significantly with AC voltage drop, let alone during the wave portions of inverse polarity. :unsure:
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I see what you mean - hard to find....unreasonably hard to find. These should be fairly common.

 

Have you tried these links?

 

http://www.axesrus.co.uk/Electronics-Pots-s/1951.htm

 

http://www.digikey.com/catalog/en/partgroup/450-series-stock-pot/5649

 

http://uk.farnell.com/rotary-potentiometers

 

http://www.surplussales.com/potentiometers/PBM-Shafted/PBM-Shafted-4.html

 

Good luck!

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Thank You, Jdgm!

 

Unfortunately, the pots in these links won't fit either.

 

What I have found are a pair of CTS 2K new-old-stock pots. Shaft and base diameter is ok, but the lenght of the shaft and the threaded sleeve is too long. I have disassembled one pot, and filed to size:

 

HPIM6197_zpsso2hda1c.jpg(left to right: the original pot; stock NOS CTS 2K pot; modded CTS pot).

 

Now, I have to figure out how to fit the pot knob securely...the knob is another thing would be very hard to find if damaged: a "reflector" with Bass written on it.

 

Bence.

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Hello Badbluesplayer.

 

Your suggestions were useful - my Dad said the same thing with resistors (He is a technician), but it hurts so bad to tinker vintage guitar's electronics. [unsure]

 

Well, this part of world You don't see many Les Paul Recordings (or other 30+ years old Gibsons).

 

Bence.

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Hello.

 

The old pot just died. It only let the signal through intermittently. I had to wiggle to pot to make the guitar sound. As I disassembled, it fell apart. Without skills, I wouldn't bother to restore it.

 

As it seems now, a fellow member on Donny's FB page got one for sale. Hopefully, it is what I need. If not, I will use the one I crafted.

 

Thanks everyone!

 

Bence.

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