What pot for 5th knob mod

Modern years of Rickenbacker Guitars from 1984 to the present

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booker
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What pot for 5th knob mod

Post by booker »

As in the title I wonder if you guys can help me out with finding the right push pull pot for 325v63 5th knob modification. Rickenbacker does not make required 500k ohm push pull DPDT pots at this point and given various versions of this pot currently available I am not sure which one would suit 335v63 the best.
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iiipopes
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Re: What pot for 5th knob mod

Post by iiipopes »

I can't tell you what DPDT push-pull pot will work, because I only used the RIC DPDT push-pull pots when they were offered some years ago, and still have a couple if I ever need them. But I can give pointers as to what to look for:
1) 500 kohm push-pull pots will retain as much brightness as possible, because they have less loading to ground than does a 250 kohm. Yes, I know the 5th knob is not grounded on the third lug, but still....
2) Measure the depth of the interior of the body from the "floor" of the control cavity of the instrument to the bottom of the plate to see how much room you have to work with. Then consult the physical specs for any DPDT pot being considered to see if the depth of the body, pot and switch, is that measurement or, preferably, less.
3) To get the pot closer to the control plate, some pots have an index tab moulded into the body of the pot on the shaft side as an index to prevent rotation of the body of the pot. To gain that tiniest bit extra depth, you can take a pair of pliers and remove the tab.
4) Since we have limited space to work with, Don't worry about putting the extra nut underneath the plate. The serrated lock washer is enough, and even that may not be necessary. But make sure you do use the plain washer on top under the shaft nut to secure the pot so it won't come loose and rotate or spin.
Hope this helps.
booker
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Re: What pot for 5th knob mod

Post by booker »

iiipopes,
Thank you for the explanation. Would 1meg push pull pot work in your scheme or it has to be 500k pot?
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iiipopes
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Re: What pot for 5th knob mod

Post by iiipopes »

booker wrote:iiipopes,
Thank you for the explanation. Would 1meg push pull pot work in your scheme or it has to be 500k pot?
A 1 meg pot will cause too much of a volume jump; it will not be smooth, as the purpose of the 5th knob is to fine tune the volume level of the neck pickup to match the bridge pickup. A 1-meg will be essentially all-or-nothing, the antithesis of what the 5th knob is all about.
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aceonbass
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Re: What pot for 5th knob mod

Post by aceonbass »

I use Bourns push-pull 500 pots in this application. They are very similar to the old Alpha pot RIC used, but are a better design with smoother action. Since the vintage tone cap is on the bridge pickup circuit, I use it in place of the bridge tone pot like RIC does on the basses. Although it's function is still the same here, it just makes more sence to me. Like the old alpha pot, the Bourns pot requires 1" of cavity depth. Since the guitar, as well as 4001/3 basses is 1.25" thick, routing the cavity to the proper depth does not compromise the area in any way.
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iiipopes
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Re: What pot for 5th knob mod

Post by iiipopes »

aceonbass wrote:I use Bourns push-pull 500 pots in this application. They are very similar to the old Alpha pot RIC used, but are a better design with smoother action. Since the vintage tone cap is on the bridge pickup circuit, I use it in place of the bridge tone pot like RIC does on the basses. Although it's function is still the same here, it just makes more sence to me. Like the old alpha pot, the Bourns pot requires 1" of cavity depth. Since the guitar, as well as 4001/3 basses is 1.25" thick, routing the cavity to the proper depth does not compromise the area in any way.
Dane has much more experience with which push-pull pot to use. Follow this advice. Now when folks ask me about which push-pull pot to use, I know what to tell them. Dane, thanks.
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