650C potentiometer discovery

[analogpackrat]

I bought a used '00 model JG (rocks!) 650C about five or six years ago. While I really like the looks and the way it plays I've never liked the tone very much. It has always seemed dead/dark/veiled somehow. Recently I started thinking about trying a coil split or even swapping out the HBs for HiGains. Luckily I opened it up and poked around before buying any new parts. Here's what I found in this completely factory original guitar. The volume pots measured 168k and 173k! The tone pots measured 162k and 166k! I know these are supposed to be 250k according to the published wiring diagrams and even a 20% variation can be expected in some pots, but here we're talking about 30% at best and 35% at worst and all are on the low side.

That seemed like at least part of the trouble so I ordered two 500k CTS pots along with some parts for another restoration project. I changed out the volume pots for the new 500k units and now the guitar sounds like I would expect! The tone is alive and dynamic with more midrange grunt than a HiGain. I might put some 250k or 330k tone pots in next, but that is less of an issue for me. I wonder if RIC got a bad batch of 250k pots back in 1999 or 2000? Has anyone else found this? I imagine it would be less noticeable in a single coil guitar, but anything with a HB would definitely sound darker than it should. If you have a 650 model it seems worth a check--especially if you find it too dark sounding. $20 in pots is a lot cheaper than a pickup swap!

Doug

p.s. Before anyone asks...yes I did measure the pots correctly. The posted numbers are from the outer lugs--volume pots out of the guitar, tone pots still in, tone up all the way (the DC measurement is isolated by the tone caps).

[johnallg]

Here is the schematic for your 650C:

http://www.rickenbacker.com/pdfs/19501.pdf

The basses with HB1 pickups used to use 500k for both tone and volume but now RIC has standardized all pots to 330k.

[aceonbass]

Doug.....Every single RIC supplied pot I've ever purchased was in the range you specified for yours, regardless of what it was SUPPOSED to be. At that time I was buying the parts and having someone else do the wiring. After I learned to do my own wiring, and bought a multi-meter, I discovered the true value of my pots and and started making my own harnesses with the correct values. Changing to 250K or 330K pots, at least on the volume, will darken your tone again. While your at it, try swapping out the stock .047 tone cap for a more humbucker friendly .022 cap. This will brighten the tone even more. Since I've started doing my own wiring, I've discovered a world of tone I didn't know existed with Ricks, as well as other basses.

[analogpackrat]

John--yeah, that is the diagram I was referring to, but I misremembered that the tone pots are shown as 500k.

Dane--interesting. I confess that except for this guitar I have not checked the pots in my other Ricks. Since I have the original guard/harness out of my '64 375 I checked it. Guess what? Volume and fifth knob are all in the 160-180k range! The tone pots on this one are 500k which was a surprise. I need to check my other Ricks. I may buy some CTS tone pots as well and at that point would try swapping out the tone caps--it does get dark fast with the stock caps when turning the tone down.

[paologregorio]

This is quite interesting.

[Seans]

I'm surprised the percentage went on so late with CTS, the pot's you can buy now are really close to spec. Although, I have a 64 and all the pot's are very close to spec?.